After the Permian, the Gondwana Land and Eurasia were separated by the wide Tethys Sea. The fossils clearly indicate that between Permian and early Tertiary times a direct sea-connection existed between the present Indian Archipelago and the Mediterranean region, based upon the fossil assemblages which are practically indentical. In some cases they exhibit variations and specific differences, which indicate the formation of temporary land bridges or other barriers to the interchange of faunas within the Tethys Sea. But in the Eocene the water connection between the Mediterranean region and the East Indies was definitely severed by uplift, thereby cutting the Tethys area into a number of marine basins mutually separated by broad land areas. The Indo-Pacific faunal province with its more or less autochthonous development of the marine fauna is of post-Mesozoic age.
We have seen in the preceding paragraphs that in the Younger Paleozoic the East Indian area was submerged by seas, stretching between islands and land-masses. The crust at that time has been formed by older major cycles of mountain building, of which very little is known.
In the Young Paleozoic a great cycle of mountain building began in this area, which has developed since then in successive phases throughout the Mesozoic, Tertiary and Quaternary. The first indication of important differences of altitude at short mutual distances are found in West Borneo, where the Permo-Carboniferous occurs in littoral and neritic as well as deep-sea facies. Similar conditions may have occurred at that time in the Malay Peninsula.
The Mesozoic of the Indian Archipelago is characterized by the formation of parallel belts with sediments of widely different facies, which indicates that at that time the process of mountain building was in full swing.
In the Tertiary and Quaternary the orogenic conditions continued in other orogenic belts, which had shifted sidewards with respect to the Mesozoic ones. At present the orogenesis has been completed in the Mesozoic orogenic belts, whereas the younger ones still are in a state of active mountain building.
A synopsis of the stratigraphy of the Mesozoic has been given by WANNER (1931) and UMBGROVE (1935 a). For the sake of brevity in this chapter only some later contributions to the Mesozoic stratigraphy of Borneo, Sulawesi, Misool, Seram, Timor and Papua will be discussed. For further details, also for other islands, the reader is referred to the discussion of the regional geology in Chapter v.
B.5. MESOZOIC IN BORNEO
Triassic in Borneo. The researches by ZEYLMANS VAN EMMICHOVEN in Central and West Borneo yielded important results for the stratigraphy of the Triassic (1938, 1939). Like the Permo-Carboniferous of this area, the Triassic occurs in a volcanic and a non-volcanic facies (1938, p. 138):
The normal sedimentary facies of the Upper-Triassic is a pronounced flysch type; it consists of conglomerates, polymict sandstones, clay-sandstones and clay-shales;
limestones are completely absent. The conglomerates are composed of detritus of acid plutonic rocks, the above mentioned Permo-Carboniferous rocks and schists. In numerous places, scattered all over the area, KREKELER found Monotis and Halobia; KROL had mentioned previously, in 1930, the fossils Steinmannites n.sp., Pseudomonotis cf. ochotica, and Monotis sp., determined by GERTH, who concluded from these fossils, without reserve, a norian age.
It is of interest that there occurs in many localities a greyish-blue clay shale, which has a black streak, due to its graphite content, which has been proved paleontologically in various places to be of upper-Triassic age. This rock, which is unknown in any other formation of West Borneo, is so characteristic that it can be considered an index-marker for the Upper-Triassic in this area.
The volcanic facies of the Upper-Triassic consists of effusiva and ejectamenta of an acid to intermediary-acid composition, which usually forms a transition to alkali- rocks (quartz-keratophyres to keratophyres). In some places their upper-Triassic age could be determined paleontologically.
Comparison of the Permo-Carboniferous and Upper-Triassic in West Borneo with Molengraaff's Danau Formation. The new results of the Geological Survey in the Sanggau-Sarawak area of West Borneo shed a new light on the age and facies of the classical "Danau Formation" as distinguished by MOLENGRAAFF (1900) in the Upper Kapuas area. Here again ZEYLMANS VAN EMMICHOVEN (1938. p. 138) can be quoted:
"Primarily the Permo-Carboniferous is characterized by the basic volcanic facies and by the chert facies. These types can be entirely correlated respectively with the Pulu-Melaju series and the siliceous series of MOLENGRAAFF'S Danau Formation, consisting of jasper, radiolarite, siliceous slate and cherts. On the one hand the chert facies (especially in the South of the area under discussion) is distinguished by its predominantly light colouring and often cavernous character, but on the other hand (in Sarawak) there are transitional types, which cannot be distinguished from the typical siliceous rocks of the Danau Formation. Also other rocks from the Permo- Carboniferous, such as phyllites, clay slates, and limestones, are represented in the Danau Formation. But the quartzites and sandstones, which MOLENGRAAFF includes also in his Danau Formation, do not occur in the Permo-Carboniferous of Sanggau-Sarawak; they belong to the Triassic. If this Permo-Carboniferous and Upper-Triassic of Sanggau- Sarawak were as intensively folded as the Danau Formation in the Upper-Kapuas area, two distinct zones would also have resulted there. In that case the two "key-series" of the Permo-Carboniferous would have been interfolded with the Triassic to such an extent that both formations would have to be considered as one unit. MOLENGRAAFF'S Danau Formation as a whole should be correlated, therefore, with the Permo-Carboniferous and the Upper- Triassic, whereby the two key-series should be correlated with the Permo-Carboniferous 1).
The presence of the coarser clastic sediments in the Danau Formation has often been raised as an unsurmountable objection against the deep-sea facies of the radiolarites. This objection now appears to be faulty, because with intensive isoclinal folding it is to be expected that conformable alternations of (Permo-Carboniferous) cherts and (upper-Triassic) conglomerates originated. This would also apply to the Sanggau-Sarawak area. However, with the removal of this objection, not all objections against the deep-sea character of the Danau Formation are explained. In the southern part of the Sanggau-Sarawak area the cherts came into being as a result of silicification of originally totally different rocks. The siliceous facies is, consequently, not a primary feature, and therefore, it can not be considered as characteristic for the conditions of the sedimentation. Also the presence of Radiolariae, which in MOLENGRAAFF'S days still counted as a criterion for abyssal deposits, has now lost its significance in this respect. However, the fish-teeth with dissolved dentine, the manganese nodules, and especially the uniform development in a comparatively narrow, very long zone, which extends right across all of Borneo, still are strong arguments for a pelagic and deep-sea facies. In MOLENGRAAFF'S last paper concerning this problem (1922), he was acquainted with the westward extension of the "radiolarite-zone" only up to the North of the Lake- district. At present it can be traced farther in WNW- direction up to Kuching; consequently it forms a rather narrow belt, slightly convex to the South, which extends from Kuching to Berau over a distance of 800 km.
MOLENGRAAFF'S conception (1922), that the siliceous facies of the Danau Formation originated in a narrow, very deep-sea, is therefore still possible. As is proved now in Sanggau-Sarawak, this deep trough passed southward over a short distance into a shallow sea, in which the above mentioned Permo-Carboniferous was deposited, the normal sedimentary facies of which is undoubtedly of a neritic character, as appears from the presence of combustible shales and limestones with Fusulinidae and Bryozoa. In any case, the Danau Formation has not an oceanic facies, as was already pointed out by MOLENGRAAFF in 1922.
B.5.1.1. Jurassic in W- end SE-Borneo.
The age-determination of Jurassic areas of the Chinese Districts in West Borneo, surveyed by Wing Easton (1904), was based on Protocardia, Exelissa and Perisphinctes W AAG. In later years these fossils proved to occur also in the Lower Cretaceous, so that the Jurassic age of these areas is not longer proved (ZEYLMANS VAN EMMICHOVEN, 1938. p. 139). In the Meratus Range of SE-Borneo, KOOLHOVEN (1935), distinguishes two Jurassic formations: the Alino Formation and the Paniungan Beds. The Alino Formation is characterized by the association of radiolarian cherts with ophiolitic effusive rocks. Its age is not stated by key-fossils. KOOLHOVEN compares it with MOLENGRAAPP'S Danau Formation, presuming a Jurassic age. But after the revision of the age of the Danau Formation by ZEYLMANS VAN EMMICHOVEN this argument for a Jurassic age of the Alino Formation is no longer valid. However, in Chapter V arguments will be advanced, based on the geotectonic evolution of this area, that indeed the Alino Formation has a Jurassic age.
The Paniungan Beds have a more neritic facies. VON KOENIGSWALD determined in calcareous sandstones of this formation the gastropod Cylindrites, which fossil is known in Europe from Jurassic to Lower Cretaceous (see KOOLHOVEN, 1935).
B.5.1.2. Cretaceous in West and SE-Bomeo.
An important contribution to our knowledge of the Cretaceous in West Borneo was made by ZEYLMANS VAN EMMICHOVEN (1936, 1938, 1939). In the Seberuwang area, SE of Semitau, upper Kapuas, a detailed stratigraphy of the entire Cretaceous could be given with the aid of an extensive collection of fossils, examined by VON KOENIGSW ALD. The fossils of Seberuwang and their state of conservation resemble very much those of the Dusun Pobungo locality of Djambi, Sumatra, described by BAUMBERGER (1925).
MOHLER (1946 b), found in the material in which the ammonites of Seberuwang were embedded, some smaller Foraminifera, among which Trocholina PAALZOW. The latter genus has to date been known only from the Jurassic of Central Europe (Bajocian-Tithonian). This is the first find of this fossil in SE-Asia, where it appears to occur in the Lower Cretaceous.
This Cretaceous transgresses in the North over the Bojan Formation (for the greater part Upper- Triassic) and in the South it is unconformably overlain by the paleogene Plateau Sandstones.
KOOLHOVEN (1933 c, 1935), described the cretaceous formations in the Meratus Mts of SE-Bomeo. OrbitoUna-bearing limestones were formed in the Middle Cretaceous, and the Manunggul Formation with Nerinea (Ptygmatis) cf. requieni D'ORB. belongs to the Upper Cretaceous (see also MARTIN, 1889 a&b).
These middle-upper cretaceous beds are certainly younger than the peridotite massif in this area. On the other hand, these ultra-basic rocks are intrusive in the Paniungan Beds, which are probably of upper-Jurassic age. This is the only instance in the Indian Archipelago, where the age of the ophiolitic intrusions could be fixed between rather narrow limits; they were probably emplaced in the Lower Cretaceous.
These ophiolites are accompanied by intrusive breccias. In the peridotitic Pamali Breccia diamonds have been found which is one of the primary occurrences of the diamonds found downstream in the alluvial deposits of the Martapura area.
B.5.2. MESOZOIC IN SULAWESI
Since the appearance of RUTTEN'S book in 1927, important contributions to our knowledge of the Pre-Tertiary in Celebes, have been made by BOTHE (1927), BROUWER (1934, 1947), KOOLHOVEN (1930, 1932), VON Lóczy (1933/,34). Some critical remarks on the publications by VON Lóczy and his collaborators, have been published by members of the geological survey: HETZEL (1935), TAN SIN HOK (1935 d), and OOSTINGH (1935 b ). WANNER (1940, p. 97) supposes that Stomiosphaera moluccana occurs in limestones with Belemnites and Radiolaria described by VON L6czy (1934). WANDEL (1936, p. 515-16) described molluscs from the Nambo River in the East arm with Aucella malayo-maorica KRUMB. (Upper Oxfordian).
B.5.2.1. Central Sulawesi and adjacent parts of the island.
BROUWER (1947) gave a synopsis of the results of the geological explorations in Central Celebes in 1929. From this paper the following relative to the stratigraphy of the Mesozoic in Central Celebes can be quoted:
Triassic. "Triassic lamellibranchs (Casstanella or Hoernesia) have been found in marly limestones East of Era, in the eastern zone of Central Celebes (BROUWER, 1934, p. 175). Grey, red, brown and greenish limestones and marly limestones, which partly contain globigerines, radiolarian cherts and dark grey bituminous, partly crystalline limestones and marly limestones, which sometimes contain bands of dark coloured chert, occur in the same region. The last mentioned rocks bear some resemblance to the bituminous rocks in the eastern peninsula, which are probably of Permo-Carboniferous age (VON Lóczv, 1934, p. 237, 295, 296). In connection with the complicated structure, rocks of widely different age may occur together in the same complex.
Deposits, which mainly consist of shales and sandstones in the monotonous alternation of the flysch facies, more or less resembling the upper-Triassic flysch series of the neighbouring island of Buton (HETZEL, 1936), are of widespread occurrence in Celebes. In the SE arm fossils of upper-Triassic age have been found in a series of slightly metamorphic slates with intercalated sandstones (BOTHE, 1927). Other rock-series in the SE arm, Sand E of Lake Towuti, contain Globigerinidae.
Undeterminable remains oflarger perforate Foraminifera have also been found. The occurrence of grains of picotite or chromite in calcareous sandstones of this series points to an age younger than that of the ultrabasic rocks (BROUWER, 1934, p. 54-75). Eocene Camerina have been found in the northern peninsula in the slightly metamorphic Tinombo Formation (BROUWER, 1934, p. 59, 206, 207). In dark slates, belonging to the Bobakan Complex in western Central Celebes, ammonite remains have been found (REYZER, 1920, p. 164). A possibly cretaceous formation in the eastern peninsula, which contains micaceous sandstones and bituminous limestones, may also be mentioned here (VON L6CZY, 1934, p. 254).
It is clear that rock series of different age are developed in a flysch-like facies and, therefore, an upper-Triassic age cannot be derived from the facial characteristics of the rocks.
In the eastern peninsula, various fossils have been found as proof of the occurrence of the Triassic (VON LÓCZY, 1934, pp. 238-244). Among the different rocks of this age are marly and arenaceous limestones, sandstones argillaceous sandstones and massive coral limestones in which upper-Triassic brachiopods have been found (various species of MisoJia, Cruratula subeudora, Spiriferina cassiana, Rhynchonella arpadica). The massive limestones (Tokala Mountains), which are considered to be of upper- Triassic age, rest upon bituminous limestones for which a Permo-Carboniferous age has been considered highly probable by VON LÓCZY (1934). The Lower and Middle- Triassic have not been indentified. Jurassic.
As yet comparatively few fossil localities are known ~_ in the Jurassic of the investigated region (BROUWER, 1934, p.56, 172-179). Fossils, which prove a Jurassic age with certainty, have been found in the eastern and southeastern peninsula and in the regions, which connect these peninsulas with Central Celebes (BROUWER, 1934; VON LÓCZY, 1934; WANNER, 1931).
The Lower Jurassic (Lower Lias) is represented by a dark grey, brecciated limestone with Arnioceras cf. semilaeve in the eastern peninsula (WANNER, 1931, p. 5901)).
The Middle Jurassic as yet has not yielded characteristic fossils.
The Upper Jurassic has been located at various places in the eastern arc of Celebes. Belemnites in red, grey or white limestones and marls, which often contain radiolarian chert, prove that these rocks belong, partly at least, to the Upper Jurassic. The Aucella Zone of the Oxfordian, which has a large extension in the eastern part of the Malay Archipelago, is also found in the eastern arc of Celebes (WANDEL 1936, p. 5-15).
A large part of the Globigerina and Radiolaria bearing rocks, which are widely spread in Central Celebes and in the peninsulas, may be of Jurassic age. Cretaceous.
In Celebes, different facies of the Cretaceous are found. A facies of the Middle to Upper Cretaceous, consisting of dense limestones, marly limestones and shales with planktonic Foraminifera ("Globotruncana-fauna"), is of widespread occurrence in the eastern Malay Archipelago and is found in the eastern arc of Celebes.
In many respects they resemble the couches rouges of the Alps. Similar bathyal deposits are considered of Jurassic age and it is possible that sedimentation was continuous from the Jurassic to the Upper Cretaceous. A series, containing micaceous sandstones and bituminous limestones in the eastern peninsula is possible of cretaceous age (VON Loczv, 1934, p. 252).
In the Pangkadjene region in the southern peninsula a "clayshale-graywacke-arkose" formation ('T HOEN & ZIEGLER, 1917, p. 243) is possibly of cretaceous age. It disconformably overlies an apparently conformable series of crystalline schists (in combination with serpentines), quartzites and cherty shales and it is unconformably overlain by eocene sediments. This possible cretaceous formation has been compared with the upper Palelo Series of Timor (BROUWER, 1942), which partly is Upper Cretaceous and disconformably overlies a series of crystalline schists (in combination with ultra-basic rocks) and radiolarian cherts.
Formations known as the Volcanic Formation and the Maroro Formation have a large extension in West Central Celebes. The Volcanic Formation mainly consists of effusive rocks, volcanic tuffs and breccias, shales and slates, sandstones and conglomerates. The Maroro Formation, in many localities, consists of Globigerina-bearing variegated shales, marls, slates, sandstones and calcareous sandstones, limestones and conglomerates. Both the Volcanic Formation and the Maroro Formation are partly of Tertiary age.
In connection with a complicated structure, rocks of different age may now be found in close association in the same complex. Our knowledge of the distribution of Mesozoic rocks in West Central Celebes is still very incomplete. Ammonite remains have been located near Bobokan (REYZER, 1920, p. 164); limestones West of the Latimodjong Mountains contain Orbitolina and the cretaceous, probably upper-cretaceous, the coral Astrarea cf. columellata (BROUWER, 1934, p. 58, 168).
Some Globigerina and Radiolaria bearing rocks in the northern peninsula are possibly of cretaceous age (KOPERBERO 1928, I, pp. 21-27; SCHUBERT, 1913, p. 142). Diabases and tuffs, graywackes and other detrital rocks are associated with them. A flysch-like formation in the Tinombo region, in which eocene Foraminifera have been found, is accompanied by reddish, greenish and gray marls and Globigerina limestones. These, as similar rocks in the western part of Central Celebes, may be, at least partly, of young-Mesozoic age."
East arm of Celebes. The Nederlandsche Pacific Petroleum Maatschappij has put at the disposal of the present author a reconnaissance report on the East arm of Celebes by its geologist R. H. HOPPER, dated May 23, 1941. From this report some passages will be quoted in this chapter in so far they provide new data on the stratigraphy of the East arm. The area covered by HOPPER'S maps and report coincides more or less with that of KOOLHOVEN'S survey of the East arm of Celebes and the Banggai Archipelago (1930).
Triassic and Jurassic in the East arm or Celebes. (Fig. 43). "According to HOPPER (l.c.) this unit B of his stratigraphy ') consists of conglomerate, sandstone and quartzite, siltstone, slate, limestone, and radiolarian chert. The rocks are so intensely deformed by folding and faulting that it was not possible in a reconnaissance survey, to work out the stratigraphic sequence or even to determine with certainty which of the rock types are the more important in making up the section. It seems probable that limestone is areally more widespread than any other single type of sediment. The limestone is hard, crystalline, fine-grained, and white or flesh coloured to dark bluish gray. In general it shows no bedding, but locally lenses of reddish brown radiolarian chert, 2 to 4 cm thick, bring out the stratification. The limestone is almost entirely non-fossiliferous; at one locality, however, a sample showed indistinct ammonite-like impressions.
Hard, chiefly non-bedded slate, mostly dark bluish gray but occasionally greenish or reddish, makes up a considerable part of the Mesozoic section. The slate contains small quartzite laminae. No fossils were found in it.
Sandstones, siltstones, and quartzites whose weathered colours include green, blue, gray, pale yellow, and red, are present along the Singkojo-uso River. Siltstones and fine-grained sandstones are the most common types. In a one metre thick siltstone bed the only identifiable fossils of this unit were collected (Singkojo-uso River; see below).
The conglomerates are hard, well-cemented, and moderately well stratified in beds, 10 cm to 2 metres thick. Commonest rock types among the boulders, whose diameters generally range from 2.5 to 10 cm, are pink granite and quartzite.
Structural complexities of unit B are such that very mapping would be necessary before its thickness be estimated with any accurancy. It is believed, however, that this unit cannot be less than two or three hundred metres thick.
The true stratigraphic base of Unit B was not observed. lower contact, wherever seen, is an intrusive contact basic igneous rock. Unit B is overlain unconformably • lower and upper miocene rocks.
WANNER (1910 c) applied the name "Toeli limestone" all or part of the rocks here referred to as Unit B. He d no determinable fossils in this formation, but tatively correlated it with the Jurassic of Buru on lithology.
A fairly well preserved ammonite, found in the above mentioned locality of the Singkojo-uso River, was identified VON KOENIGSWALD as Harpoceras cf. toarcense D'ORBIGNY, of lower-Jurassic age (Lias). This fossil had previously been reported from Jefbie and Fialpopo, small islands in the Misool Archipelago.
In somewhat similar rocks in the Tokala Mts, 10 km NW of Kolo Bay, VON Lóczy (1933/,34) found Triassic well as Jurassic fossils 1).
Thus it is possible that Unit B contains both Triassic and Jurassic sediments. Strata of these ages occur in numerous places throughout the Timor - East Celebes geosyncline (UMBGROVE 1938 a, pp. 10, 14).
The sediments of Unit B are probably wholy of marine origin. Both shallow- and deep-water deposits are represented.
B.5.2.2. Cretaceous in the East arm of Celebes.
The Unit C is probably of cretaceous age. Exposures were found only in the eastern part of the East arm.
Unit C consists of soft to firm. light buff to purplish gray (weathered) micaceous siltstone and shale, with occasional harder interbeds of fine-grained limy sandstone. Stratification is in general rather poorly developed, with beds 0.3 to 3 metres thick. Foraminifera are common.
The maximum observed thickness of Unit C, measured along the Biak-Poh road, is 210 metres. The complete thickness may be much greater, however, for the base of the Cretaceous is not exposed. Its lower contact, whereever exposed, is either a fault contact or an intrusive contact with basic igneous rock (Unit F).
The Cretaceous is overlain disconformably by Paleogene or lower Miocene (Unit D or Unit E). The Paleogene- Cretaceous contact is exposed only on the Biak-Poh road about 2 km South of Mahap and on the Poh-Pagimana road near Talojon; angular unconformity is very slight or lacking, but the basal part of the paleogene limestone is conglomeratic.
Just North of Mahap, and at two localities along the Poh-Pagimana road, the lower-miocene Unit E directly overlies Cretaceous. There is no noticeable angular unconformity between the Cretaceous and the overlying Miocene, the Miocene however, predominantly a limestone unit, is sandy and conglomeratic at its base.
The N.P.P.M paleontological laboratory at Medan reports that Foraminifera are common and well preserved in the cretaceous samples submitted from the East arm of Celebes. Characteristic cretaceous forms found in these samples include:
Globotruncana rosetta (CARSEY)
Guembelina globulosa (EHRENBERG)
Pseudotextularia frusticosa (EGGER)
Globotruncana-bearing Cretaceous sediments are found widely distributed throughout the Timor - East Celebes geosyncline and in the Vogelkop of New Guinea (UMBGROVE, 1938 a, p. 20).
According to the paleontological staff, the fauna of Unit C indicates that the shales and sandstones of this unit were laid down in shallow warm water.
Age of the basic and ultra-basic intrusive rocks in the East arm of Celebes. Basic intrusive rocks, such as gabbros, peridotites and serpentines, are widely distributed in the East arm, but there is considerable divergence of opinion as to their age.
WANNER (1910 c) and HoTZ (1913) agreed that the basic plutonic rocks intrude the lower miocene sediments. The former believed that these rocks intruded also the "Celebes Molasse" (Mio-Pliocene) .
RUTTEN (1927, p. 577-580) and KOOLHOVEN' (1930), concluded that these basic intrusive rocks were probably of Mesozoic age, for gabbros and peridotites elsewhere in the Archipelago are Mesozoic.
VON Lóczy (1933/'34), dated their phase of intrusion as post-Upper Cretaceous and pre-Upper Eocene, on account of contact phenomena in Jurassic and cretaceous limestones (marmorization, silicification) and the presence of boulders of gabbros and serpentine in upper eocene limestone. KOOLHOVEN (1930), observed also macroscopical serpentine fragments in lower-miocene limestone.
HETZEL (1935, p. 30) draws attention to a report of Dr H. W. SCHAAD 2), who worked together with VON L6czy in the area of North Bungku and Bongka. SCHAAD observed rounded fragments of ophiolitic rocks in presumably upper-Jurassic, Belemnites-bearing limestones and marls. This occasioned UMBGROVE (1935 a, p. 148, 150), to the remark that the Mesozoic basic eruptiva of the Timor-East Celebes Zone might belong for, the greater part, if not entirely, to the Lower Mesozoic (Trias).
HOPPER, on the other hand, has a similar opinion as WANNER and HOTZ, that the ophiolites are Neogene. HOPPER assigns a middle-miocene age to them (Unit F of his stratigraphy). This geologist bases his opinion on the observation of occurrences of ophiolitic rocks in the Old-Miocene in the Poh-Mahap district, and basic dikes in the Basabungan River at the North coast (South of Pangimana). The rocks first mentioned are explained by KOOLHOVEN (1930), as the result of imbrication by tectonic forces, so that they are not true intrusions.
The Basabungan dikes, however, seem too coarse- textured to be feeder dikes of the later basaltic volcanics at the base of the "Celebes Molasse". These dikes are mostly fresh and fine grained near the contact. Furthermore, they are partly serpentinized, whereas the younger volcanics are quite fresh. These basic dikes in the Basabungan River are considered by HOPPER as true offshoots of the main plutonic mass.
In this relation attention may be drawn to the observations of ROOTHAAN (1928), in the Talaud Islands, where the main intrusion of the basic igneous complex occurred after the (Mesozoic?) slates and radiolarian cherts and before the basal tertiary breccias, which contain its denudation products. But, most probably, the base of the series of sandstones and marls (Lower Miocene?) has also been intruded by basic igneous rocks. Therefore, two phases of basic igneous intrusions have probably occurred in the Talaud Islands, which form the northern extension of the East Celebes Zone.
This might also be true for the East Celebes geosyncline. For the data at hand suggest that the main phase of intrusion occurred at the end of the Mesozoic or the beginning of the Tertiary, and an after-phase in the Young Tertiary.
SCHAAD'S observations indicate that there has also been an older, pre-upperJurassic phase of ophiolitic intrusions.
Such ophiolites are usually connected with geo-synclinal downwarps, and it is conceivable that this process was repeated several times. In Chapter V the conception will be given, that in the course of the Mesozoic, Tertiary and Quaternary a system of crustal waves developed from the Celebes Basin in a southward direction. In the migrating foredeeps of this system basic and uItra-basic magma ascended, forming parallel zones of ophiolites of different age, which were thrust southward in the course of the process of orogenesis.
Age of the ultra-basic intrusive rocks in the Southeast arm of Celebes. In the Southeast arm of Celebes a large intrusive mass of peridotites and serpentines occurs in the Verbeek Mountains and farther southeastward, while several smaller outcrops also are found in the southern part of this arm (i.e. around Kolaka) and in the islands Wowoni, Buton and Kabaena. With a total outcrop area of about 8000 sq km, this peridotite massif is probably the greatest of its kind on earth (RUITEN, 1927, p. 554). It differs from the ophiolitic rocks of the East arm in the fact, that gabbroic rocks are scarcer. These are found East of Malili, in Mt Moliowo, and in the Luwuk district of the East arm; but in the peridotite massif of the Southeast arm gabbros occur only as restricted dikes and nests, being, at least partly, younger than the peridotites. The age of this enormous peridotite massif is supposed to be pre-Cretaceous, according to KOOLHOVEN (1932), who assumes that the deep-sea sediments of his lower-Marano Beds were deposited upon a sea floor which consisted partly of peridotites. These Matano beds contain Globotruncana and other cretaceous smaller Foraminifera in its higher horizons. KOOLHOVEN found neither dikes of the underlying peridotites nor contact-metamorphism in the Matano Beds. However, the Matano Beds are separated from the peridotites by an intensely mylonitized horizon some dozens of metres in thickness, consisting of serpentines with lenses of epidote-amphibolite, quartzite (piedmontite-quarzite), and floats of amphibolite, garnet-amphibolite, and mylonitized aplite. Therefore, it is possible that the contact zone between the cretaceous Matano Beds and the peridotite has been altered dynamo- metamorphically and squeezed out by later internal differential movements, or that the contact is entirely anomalous, the Matano Beds forming an overthrust nappe. So it is not certain that the Matano Beds are younger than the ophiolites.
BROUWER (1934) found South and East of Lake Towuti a calcareous clay-sandstone formation of unknown age, which is interfolded with Globotruncana-limestones and old-miocene limestones and calcareous sandstones. These formations are locally overthrusted by wedges of serpentines.
The clay-sandstone formation consists of limestones, shales, sandstones and graywackes. In calcareous sandstones and flesh coloured Globigerina- limestones clastic constituents were determined, such as quartz, feldspar, chert, fragments of volcanic rocks, moreover, the heavy fraction contains ilmenite. picotite, epidote, zirconium, titanite, tourmaline, rare garnet and rutile. The picotite indicates that this formation is younger than the basic and ultrabasic rocks. However, the age of this formation is not known. It might belong to the oligo-miocene deposits but it might also be older. The description indicates a lithological resemblance with the Pornpangeo Formation in Central Celebes, which the present author places, tentatively, in the upper- most Cretaceous, chiefly on tectonic considerations (see Chapter V. schematical sections across Central Celebes. fig. 172 on plate 20).
The problem of the age of the peridotites has neither been solved in the southern part of the Southeast arm or in Buton. BOTHE (1927. p. 100). dates the intrusion as post-Jurassic and pre-Miocene. HETZEL (1936, p. 21), says that the peridotites in Buton are older than the miocene Tondo Beds, but nowhere an intrusive contact with the Mesozoic has been observed. This author (1. c., p. 10) mentions, however, the presence of detritus of serpentine and of Globotruncana-limestone in the lower-tertiary Wani-Beds, which attests a pre-lower tertiary age of the ophiolites. Wherever the contact between Mesozoic sediments and peridotites was observed, it appeared to be an anomalous fault contact. The Trias sic flysch of South Buton contains locally dikes and sills of diabases, while strongly crushed basalt and olivine-diabase porphyrite occur in Globotruncana-limestones (Cretaceous) of North Buton.
It is conceivable that in the Southeast arm of Celebes, like in the East arm, the intrusion of the ultra-basic masses comprises a very long period, separating into several phases of activity.
The intrusion of basic and ultra-basic igneous rocks is generally associated with geosynclinal sub-sidence. It is possible that sedimentation proceeded on the seafloor, while the ophiolitic masses underneath rose to higher levels. The poorness of these magmas in volatile constituents and their relatively low temperature indicates that the contact phenomena and pyre-metasomatism in the overlying rocks and sediments are of minor importance or absent. Moreover, these magmas were not intruded diapirically by upward pressure, like the intermediary and acid calc-alkaline magmas in the orogenic phases of evolution, when geanticlines are pushed up from the geosynclines. This may be another reason, why off-shoots from the main intrusive body are rare (apart from injections of sills, due to inversion of density stratification). Therefore, such negative arguments, as the absence of contact phenomena and of intrusive off-shoots in sedimentary series, are of little value in fixing the age of the ultra-basic masses. On the other hand, such processes as silicification of limestones and other rocks, the injection of sills, or the occurrence of basic submarine volcanism might be interpreted as signs that in deeper crustal levels the front of the basic and ultra-basic magma was rising.
The author is of the opinion that the emplacement of the peridotite massif in the Southeast arm of Celebes occurred during the Mesozoic geosynclinal subsidence, and that its intrusion was completed at the end of the Mesozoic.
B.5.3. MESOZOIC OF MISOOL
Misool occupies a singular position in the eastern part of the Archipelago; it lies more or less outside the reach of the various younger orogenic systems which can be distinguished in that area. Consequently. its sedimentary strata are generally only gently tilted, the stratigraphical succession being clear. Moreover. these Mesozoic deposits are rich in well preserved fossils and the series is rather completely developed. Therefore, Misool can be considered as a key area for the Mesozoic stratigraphy in this part of the Archipelago.
A summary of the Mesozoic stratigraphy of Misool has been published by WANNER (1931) and UMBGROVE (1935 a); additional data on Foraminifera of the Main and Lower Cretaceous were given by WANNER (1940). while WANDEL (1936) described the Jurassic molluscan fauna of Misool. Furthermore, J. VOGLER (1941) described the upper-Jurassic and cretaceous faunae of microfossils of this island. The oldest member of the Triassic is a flysch- like series of shales and sandstones (Keskain Beds) with lower carnian or perhaps even ladinian Daonella and Halobia. According to Dr Fr. WEBER • the Keskain Beds are unconformably overlain by the lower norian Nucula-marls, which are an epicontinental shelf-sea deposit of only 12 m thickness (JAWORSKI. 1915).
The Nucula-marls pass upward with a graditional contact into massive reeflimestones, calledAthyrides limestones (? Middle-Upper Norian). The latter are about 50 m thick (BOEHM, 1910; KRUMBECK, 1913). They have been named after their rich fauna of Misolia (VON SEIDLITZ. 1914). containing corals. molluscs. etc.
The Jurassic of Misool lies unconformably upon the Upper Triassic. It is rather completely developed, showing affinities with the Jurassic of the Sula Islands. especially in the lower horizons. but in the higher part of the section there is a closer anology to the Jurassic of Ceram and Buru.
The Jurassic series begins with some metres of coarse grained sandstone without fossils, succeeded by marly shales and limestones of the Upper Lias- Dogger. The Oxfordian is represented by the Lilinta Beds (sandstones and shales. with Aucella, etc.) and the Kimmeridgian by the Lower Fat jet Limestones. According to WANNER (1940. p. 94), the latter (overlying immediately the Fat jet shales with Belemnopsis gerardi] contain Stomiosphaera moluccana and Cadosina fusca.
To the Cretaceous belong the Upper Fatjet Limestones (WANNER, 1910 b), which are massive limestones without chert at the base, passing upward into marly limestones, white and reddish dense limestones with chert. The Upper Cretaceous is represented by marls with inocerams, rudists, echinids, and Globotruncana.
The tables given by WANNER (1931), STOLLEY (1934. p. 484-485), and WEBER (in UMBGROVE. 1935 a), are combined in the following ideal stratigraphical section of the Mesozoic in Misool (fig. 23) and in table 9. 1).
It is remarkable that the Upper Cretaceous of Misool has the character of deposits in a shallow sea near to the coast, partly even with a deltaic bedding. On the other hand the Upper Cretaceous of Ceram (for instance that of Nief and Bula) has a bathyal facies. This indicates that Misool was situated at that time near to the northern boundary of the young-Mesozoic geosyncline of Ceram.
Recently the island of Misool has been surveyed by Dr P. M. ROGGEVEEN, geologist of the "Bataafsche Petroleum Maatschappij", from whose report the following additional data are quoted with the permission of this oil company: (see also fig. 189, and fig. 190 on plate 12).
"The Cretaceous can be divided lithologically into an upper and lower part.
The Upper Cretaceous consists mainly of browngray marly clays, partly somewhat sandy, with rare interbeds of marly sandstone. Inocerams and Globotruncana are common. Thickness about 500 m, disappearing westward under the overlapping Miocene.
The Lower Cretaceous differs lithologically from the upper part, but paleontologically it can not be separated from it. It is composed of gray, thick bedded or platy, har~, dense, somewhat siliceous limestones with chert nodules and bands. Thickness about 450 metres.
Dr W. A. MOHLER stated that in ROGGEVEEN'S samples were found: Globotruncana linnei (D'ORB.), G. stuarti (LAPP.) and the genera Venti/abre//a, Guembelina and Inoceramus.
The Jurassic is characterized by canaliculate belemnites and/or Aucella sp, and in some localities by ammonites.
In the upper course of the Fageo River, the basal strata of the Jurassic are well exposed (sandy and calcareous sandy sediments with some conglomeratic interbeds, which contain detritus of the Upper Triassic, such as quartz, shales, and lydite). This basal part of the Jurassic lies with an angular unconformity upon the Triassic. The upper part of the Jurassic section in the Fageo River is formed by a fossil-rich series of calcareous clay shales and sandy marl-limestone. The thickness of the Jurassic in the Fageo section is estimated at about 750 m. Dr W. A. MOHLER found in RooGEVEEN's samples Inoceramus ga/oi BOEHM, Aucella sp. and Harpoceras. The latter fossil is known in Europe in the Upper Lias and Lower Dogger.
The Triassic consists of a steeply dipping series of clay shales with intercalations of quartzitic (sometime) conglomeratic) sandstones. Layers of flinty slate (lydites occur in the shales, besides quartz veins and stringers".
B.5.4. MESOZOIC OF SERAM
Age revision of Loveenipora, VAN DER SLUIS (1947), critizises the current opinion that the presence of Triassic deposits on Ceram has been proved by fossils. This author comes to the conclusion that the so-called upper-Triassic molluscs in the Moluccas are stratigraphically of little value.
The coral Lovcenipora vinassai GIATIINI, and Pseudocyc/ammina occur in East Ceram in upJ2er Jurassic limestones.
The age determination of Upper Triassic in Ceram hits• often been made by means of Lovcenipora. But later researches by RENz (Abh. Schweiz. Pal. Ges. 50, 1930) and LEUPOLD and MAYNE (Eel. geol. Helv. 28, I, p. 129), have shown that Lovcenipora is known exclusively from upper-Jurassic deposits, often occurring together with Pseudocyclammina, Choffatella, and the alga Clypeina.
This association is known from southern France, Switzerland, Dalmatia, Greece, Cyprus, Japan and Sumatra. The supposed Triassic age of Lovcenipora is the result of a wrong estimate of the age of the formation in which it was originally found. MUSPER (1934) was the only author on the geology of the Indian Archipelago who did not make this mistake. Reading the publications on the geology of Central Ceram by GERMERAAD (1946) and on West Ceram by V ALK (1945), one has to boor in mind that when they speak of deposits with Lovcenipora the age is Upper Jurassic and not Upper Triassic.
A second proof for Upper Jurassic is provided by finds of Pseudocyc/ammina, occurring together with Lovcenipora in East Ceram.
Other fossils in the deposits with Lovcenipora of Ceram are the following: Pachypora (Lovcenipora) together with brachiopods and gastropods are mentioned by DENINGER (1918) from several localities; for instance, near Kaniki in Central Ceram, from which locality GERMERAAD mentions also brachiopods in Lovcenipora-limestones. KRUMBECK (1923 a), determined 29 species in DENINGER'S collection but not one is identical with previously known species. KRUMBECK'S age determination was based on some resemblance with species from the Upper Triassic of Buru, Misool and Timor. The value of this age determination is small, taking into account that Lovcenipora is restricted to the Upper Jurassic, while the Upper Triassic of Buru and Timor has been determined partly with this fossil.
WANNER (1907), described deposits of East Ceram, containing: Pachypora in tabulata (Lovcenipora vinassai), Halorella, Monotis salinaria Br., Amonotie. The presence of Monotis salinaria would be a strong indication for the Triassic age of these deposits. But according to VAN DER SLUIS, the description and reproductions in WANNER'S paper are not convincing 1).
The observations in the field are also in favour of a Jurassic age. DENINGER, visiting Buru in 1906, observed that Jurassic limestones were overlain by limestone with Pachypora. On account of this fossil he considered the latter limestones as Upper Triassic, but nowhere did he observed any traces of upthrusts.
DENINGER (1910, p. 12) wrote that the limestones with Pachypora overlie the Mefa Beds, which belong to the Oxfordian (as has been confirmed by STOLLEY, 1934), so that these horizons as well as the Daonella Beds of Ceram reach at least into the Upper Jurassic. It is regrettable that WANNER, who studied DENINGER'S material after the death of the latter, without further discussion accepted the Triassic age of Lovcenipora, which has caused much stratigraphical confusion.
In Chapter V the possibility is discussed that two flysch series might be distinguished; a Triassic flysch on Misool, Ambon, Timor, etc., and a Jurassic flysch on Ceram, characterized by the presence of volcanic components (feldspar laths).
Age of the basic and ultra-basic rocks in Ceram. The age of the peridotites, gabbros and serpentines of Ceram, which has been dated as post-Triassic by previous authors, must also be younger as the result of VAN DER SWIS' opinion that part of the "UPEer Triassic" of Ceram belongs in fact to the Upper Jurassic. Their pre-neogene age follows from the presence of lower-neogene fossils in a breccia of serpentine and limestone. VAN DER SWIS (1947) is of the opinion that the ophiolitic intrusions occurred in the Cretaceous.
This opinion is corroborated by an observation of WEBER, who observed a basaltic sill in the Upl'er Cretaceous of the neighbouring island of MisoOl (B.P.M. report, Febr. 14, 1930).
B.5.5. PERMIAN AND MESOZOIC OF TIMOR
FiG. 24. On plate 3. Geographic sketch map of Timor.
The regions in Netherlands Timor which have been mapped during the expedition to the Lesser Sunda Islands in 1937 under the leadership of BROUWER are:
I) Mollo region, and
II) Booi region (mapped by D. TAPPENBECK, 1939, Vol. I) 2) Fig. 223 on plate 27, and fig. 220.
III). Part of NE Netherlands Timor (mapped by A. L. SIMONS, 1939, Vol I).
IV)Region between Noil Tobe (Noil Tuninu) and Noil Bunu, NE of Basleo, and
V) region between Noil Bunu and Noil Aintenu (mapped by F. A. H. W. DE MAREZ OYENS, 1940, Vol. I).
VI) Southwestern Mutis region (mapped by W. P. DE ROEVER, 1940 a, Vol. II).
VII) Region in the district of Amfoan (mapped by J. H. VAN VOORTHUYSEN, 1940, Vol. II).
VIII) Miomaffo region, and
IX) Nun Pene region (mapped by F. P. VAN WEST, 1941 b, Vol. III). See fig. 229.
X) Part of the central basin of Timor,
XI) U-Oloh region and
XII) Kefamenanu region (mapped by D. L. DE BRUYNE, 1941 a, Vol. III).
The geological maps of regions in Portuguese Timor, which have been mapped in 1936 by the geologists of the Allied Mining Corporation (1937) are reproduced in Chapter V:
A. Aliambata (fig. 236)
B. Suete (fig. 238)
C. Pualaca (fig. 240)
D. Cribas (fig. 241)
Netherlands Timor. A recent advance in the knowledge of the pre-tertiary stratigraphy of Netherlands Timor has been attained by BROUWER, who made in 1937 an expedition to this island with DE MAREZ OYENS and several pupils. The results of this expedition have lately been summarized by BROUWER (1942 b), which paper will hereunder be quoted at some length in so far as it deals with the Permian and Mesozoic stratigraphy (pp. 365- 370). The Permian is discussed with the Mesozoic because these formations are intimately interfolded. The stratigraphic sequence is described for four regional tectonic units, ranging from Permian to Cretaceous or even Eocene 1).
"Several different facies representing simultaneous periods of deposition under widely different conditions are now found in superposition in the island of Timor. The principal facial changes are found in a direction normal to the longer axis of the original basin of sedimentation. We have divided the non-metamorphic Permian and Mesozoic formations into four main groups, which are of facial and tectonic significance: The Kekneno Series, the Sonnebait Series, the Fatu Complex, and the Palelo Series. Correlations can be based on a fairly large amount of stratigraphical evidence but many problems still await solution. Only some main facial groups are distinguished and the passage facies, which may also be of tectonic significance, have not been established in detail.
In the Permian striking facial differences exist between the Kekneno Series and the Sonnebait Series. Those between the Sonnebait Series and the Fatu Complex are sometimes dubious. Particularly the Triassic is exhibited in a most varied development of facies, which partly are known to continue in the Lias. Much less has become known about facial differences in younger Mesozoic time, except for those between the upper Palelo Series and the other rocks of younger Mesozoic age.
Stratigraphical tables for different regions, which have been studied in detail, are given by TAPPENBECK (1939, p.24-25), SIMONS (1939, p. 24-25), DE ROEVER (1940, p. 24-50), VAN WEST (1941 b, p. 26). 2) Kekneno Series.
This series mainly consists of sterile shales and sandstones to graywackes in the monotonous alternation of the flysch facies. The shales and sandstones are often micaceous and sometimes contain plant remains. Siliceous and iron- bearing concretions are also found. Marls, marly limestones, cherts, breccias, conglomerates are subordinate. Variegated shales and marls and deposits in halobiid facies may be like rocks of the Sonne bait Series and where similar rocks of both series occur in close proximity it is difficult to draw a sharp boundary between them. Beside Triassic rocks, fossiliferous Lower Permian has been found in the Kekneno Series (DE ROEVER, 1940).
The gases of the mud volcanoes in the island of Timor seem to originate from the Kekneno Series (WANNER, 1913, p. 148).
In the regions which were studied in detail no fossils were found younger than Triassic 1).
It is not certain, however, that the Kekneno does not comprise younger Mesozoic rocks.
The occurrence of intercalated cherts and shales with Radiolaria may indicate that clastic material was transported to deeper parts of the geosyncline during the deposition of the synorogenic Kekneno Series. That erosion of crystalline schists has played a part in the formation of the series is proved by the occurrence of schist-fragments in conglomeratic sandstones, while garnets have been found within the heavy mineral assemblages of several sandstones. Fragments of feldspar-rich volcanic rocks have alscbeen found (DE ROEVER, 1940).
The only indication that igneous rocks may occur in the Kekneno Series is the local occurrence of large detached blocks of mesocratic alkali-albitites amidst Permian rocks of this series in the SW-Mutis region.
The regional distribution of the Kekneno Series is connected with axial culminations. As this series has a low tectonic position, the largest exposure is found near the main axial culmination in the middle part of the northern half of Netherlands Timor. Sonnebait Series.
The Permian of this series principally consists of deposits of shallow depth: Limestones, marls, tuffaceous marls and tuffs. They contain a great wealth of fossils, among which corals, bryozoa, crinoids, blastoids, cephalopods and brachiopods are especially abundant. Limestones, composed almost exclusively of tests of fusulinids, are found at various places and are also considered as belonging to the Sonne bait Series.
From Lower to Upper Permian the following stratigraphical levels have been distinguished: Somohole-, Bitauni-, Basleo-, and Amarasso Beds. During the expedition of 1937 two new levels have been found: the Tea Wei Beds between the Bitauni and Basleo Beds and a zone in Lidak, which corresponds with the lowest part of the Bitauni Beds, because it only contains the more primitive ammonites of these beds (SIMONS, 1939, p. 18-20, and 99).
The Permian of the Sonne bait Series is accompanied by abundant igneous rocks of which the more acid rocks are alkali-trachytes and alkali-rhyolites, whereas the more basic ones, which have often been described as melaphyres and amygdaloidal melaphyres, appear to belong at least for a great part to trachybasalts and olivine basalts, while spiIites and poenites 2) were formed by metasomatic processes from these rocks.
Permian conglomerates occur at several places. Pebbles of various types of alkaline effusive rocks have been found in these rocks (DE ROEVER, 1942, p. 215). Conglomeratic crinoid limestones in the Mollo region contain pebbles of granite-aplite and chert. Fragments of crystalline schists have nowhere been found in these Permian conglomerates. Because conglomerates and effusive rocks of the Mollo region have been considered as belonging to the tectonic unit of the Fatu Complex (TAPPENBECK, 1939, p. 25, p. 100) they have been separated from the Sonnebait Series. We now believe that at least most of these rocks belong to the facial and tectonic unit of the Sonnebait Series.
Larger sea depths were prevalent during the deposition of the Mesozoic part of the Sonnebait Series. Cephalopod- limestones are found from the Lower- to the Upper Triassic and in the Lias. Rocks containing Halobiidae have been found in the upper parts of the Triassic. Shales and cherts partly filled with Radiolaria are found associated with them. The main development of the Lias consists of cephalopod marls and clay shales and that of the Dogger of ferruginous clay shales with concretions of clay-iron stone. The facial and tectonic unit to which the latter rocks belong is still dubious.
Dense limestones, marls, cherts, and radiolarites are of widespread occurrence in the younger Mesozoic of the Sonnebait Series. Oxfordian Aucella-limestones and cretaceous Globotruncana-Iimestones with interstratified marls and cherts occur in this series. Globigerina-Iimestones and cherts with Radiolaria may partly be of cretaceous- and partly of older Mesozoic age.
The Sonnebait Series has a large extension in Netherlands Timor. It has been eroded away where the lower tectonic unit (Kekneno Series) is uncovered. South of the central basin, where detailed investigations were only locally made during the expedition of 1937, many rocks of WANNER'S zone of Niki Niki-Baun (1913, p. 141) belong to the Sonnebait Series. This may be true also for other rocks of which the facial and tectonic group to which they belong is still doubtful, like WANNER'S Ofu Series 8).
An interesting occurrence of red deep sea clay shale in this part of the island is considered to be of upper- cretaceous age (DE BEAUFORT, 1923). The clay shales contain remains of Radiolaria, numerous nodules of manganese, and a great number of fragments of teeth, for the greater part belonging to the family of the Lamnidae. The similarity with the recent red clays from the deep sea is very striking. Fatu Complex.
The Fatu Complex comprises limestones 4), mostly massive. They have a high tectonic position. Large detached blocks of Fatu limestones have been displaced far from their original source, forming now sometimes the highest part of their surroundings. Large block fields of Permian crinoid limestones of the Sonne bait Series are also found and therefore the distinction between the Permian of the Fatu complex and the Permian of the Sonne bait Series is sometimes dubious (compare stratigraphical tables in TAPPENBECK, 1939, SIMONS, 1939, DE ROEVER, 1940). Massive, unstratified, mostly white to light pink, coarsely crystalline limestones with trochites and brachiopods in NE Netherlands Timor are grouped with the Fatu Complex (SIMONS, 1939). Rocks of this type have not been encountered in the southwestern Mutis region where the crinoid limestones belong to the Permian of the Sonne bait Series (DE ROEVER, 1940, p. 15).
In the Mollo region, crinoid limestones and igneous rocks, which have been grouped with the Fatu Complex (TAPPENBECK, 1939, p. 100) seem to have - at least partly - the same position as similar rocks of the Sonne bait Series in the neighbouring southeastern Mutis region. The conglomeratic Permian rocks in the Mollo region, which have been grouped with the Fatu Complex (TAPPENBECK, 1939, p. 25) have been mentioned already with the rocks of the Sonne bait Series.
The Triassic of the Fatu Complex is represented by masses of mostly light coloured, often oolitic limestones, which mainly are coral reefs of upper-Triassic age. Locally these limestones show a southeastern trend. In the Mutis region the small pebbles belong to porphyritic sanidine trachites. Stratified limestones are also found in the Triassic, as well as in the Lias. In stratified Triassic limestones of the Miomaffo region rounded fragments of eruptive material and many clastic albite crystals have been found. The eruptive material seems to be mostly derived from xsocratic albite-rich igneous rocks. Sheets of diabase, which have been found in Fatu limestones of upper Triasic age (BROUWER, 1918 d, p. 150-151) show that a of the eruptive rocks belongs to the Fatu Complex.
The Triassic rocks of the Fatu Complex often form picuous steep montains, which occur isolated or in groups and tower above the gentle slopes of the Sonnebait Series.•They are very numerous in the part of Netherlands Timor, North of the young central basin.
The Palelo Series is found in close relation with the crystalline schists of Netherlands Timor and both formations belong to the same stratigraphical column and the same tectonic unit. Two lithologically quite different parts of the series have been distinguished; the lower part is assumed to be much older than the upper part. The available results of the observations are at present explained best by assuming that the Upper Palelo Series disconformably overlies the Lower Palelo Series and the crystalline schists. Absence or scanty development of the lower part of the series may have a tectonic cause or may be caused by erosion before the deposition of the upper part.
The lower part of the series is of unknown age. It has its most complete development in the Miomaffo region and the succession of strata in this region has been compared by VAN WEST (1941, p. 24-25) with similar deposits in southern Celebes, SE-Borneo (Alino Formation), and Central and NW-Borneo (so-called "Danau Formation"). On the ground of these comparisons, which should only be used in a tentative way, a Permian age might be considered. A Triassic age might also be considered, the Permian rocks of which the age could be determined by fossil evidence being all deposits of shallow water depth 1). This lower part of the series in the Miomaffo region is mainly composed of radiolarian cherts, while in connection with them breccias, which are associated with igneous rocks (albite diabases) occur close to the contact with the crystalline schists. The fragments in the breccias are derived from quartz keratophyres, keratophyres, quartz- amphibole albitites, albitite diabases, and spilitic rocks. The contacts of the Lower Palelo Series with the underlying crystalline schists and the overlying upper part of the series are usually characterized by a crushed zone of several metres. In the Mollo region, the lower part of the series seems to have a scanty development.
The upper part of the Palelo Series has a much larger extension. Its age is partly fixed by the presence of the Globotruncana fauna, which points to an upper-cretaceous age of the parts in which this fauna occurs. In the Mollo region numerous (probably oxfordian) inocerams indicate an upper-Jurassic age for a certain part of the series. At some places the series seems to continue into the Eocene (TAPPENBECK, 1939, p. 49; VAN WEST, 1941, p. 33). The rocks are mainly graywackes, graywacke sandstones, tuffs, marls, shales and conglomerates, all containing volcanic material in varying quantities. Intercalated lava flows are found abundantly in the Mollo region. The conglomerates are for the greater part composed of schist fragments and, as far as the conglomerates have been studied in detail (TAPPENBECK, 1938, p. 33-34), the fragments of other rocks can safely be assumed to be derived from lower parts of the Palelo Series 2). The analysis of these conglomerates shows that rock series, which now occur in the neighbourhood, were not exposed in the region where the Palelo Series was deposited."
Portuguese Timor (See fig. 24 on plate 3 for the location of the geographical names).
The Allied Mining Corporation, technical managers of the Asia Investment Company Ltd of Hongkong, organized in 1936 an expedition to Portuguese Timor with a staff of seventeen European and ten Philippino graduates, to make a geological and topographical survey of that area. The geologists of this expedition were: W. L. CARBONNEL, N. H. VAN DOORNINCK and H. C. MORRISON; the mining-engineers were J. H. ABBOT, H. B. PARFET, B. SCHELECHOFF and R. G. TREADAWAY. The geological results of this survey appeared as Part II of the general report on this expedition (Allied Mining Corp., 1937).
This survey has considerably advanced our geological knowledge of the Portuguese part of the island, of which very little was previously known (HIRSCHI, 1907; WANNER, 1907 c).
Hereunder some stratigraphical information will be quoted from the A.M.C. report (1937). A further discussion will be given in Chapter V.
Stratigraphy and petrography.
"North Coast Schists. The characteristics of the North Coast Schists vary greatly in different localities and even within small areas. The greatest extent of these schists are in the NW area (Dilly, N-Suro, NW-Manatuto). The schists are mostly amphibolitic varieties, although mica-, quartz-, and chlorite types are also found. Most of the material shows a very prominent schistose structure. Small lenses and stringers of secondary quartz occur, some parallel and others at an angle to the planes of schistocity. The age of this formation is not definitely known, but from what information is available it has been termed Pre-Permian.
Igneous rocks outcrop among the schists in many places, especially along the North coast. Fresh specimen, gathered from a quarry near Dilly, show a coarse grained rock, made up chiefly of ferromagnesian minerals, with no visible quartz. The rock has been slightly metamorphosed, but is evidently of gabbroic character.
Lying on top of the above mentioned formations, in many places either in fault-contact or with very indistinct contacts, is a meta-igneous rock. The age relationship between these two formations is not entirely clear, although it is evident that, in some localities, the meta-igneous rock is younger. The name "Manufai Diabase" has been given to this formation as many large masses are well exposed in the district of that name in Suro.
Exposures of this rock indicate that it originally contained many of the different rock types originally found in an igneous mass. Metamorphism has caused the formation of schists, serpentines and various transitional types.
The rock occurs as:
(a) Original igneous mass: unorientated mineral components. Grades from medium grained doleritic to dense aphanitic rock.
(b) Metamorphosed: not schistose, generally showing effect of considerable pressure, some partial serpentinization.
(c) Transitional: slightly schistose type, greyish or green in colour.
(d) Schists: Amphibole schists with a little quartz, some of greyish green colour; lustrous planes of schistosity, rather often distinctly chloritic.
(e) Dyke materials: even and medium sized grains of white feldspar, hornblende and biotite.
(f) Porphyritic: this type is rare, but occurs at Marobo, with phenocrysts of plagioclase in a very fine grained mass, calcite filling in cavities.
(g) Doleritic float: containing feldspar, hornblende and pyrite, shows chloritization.
The oldest sedimentary rocks observed are of two types. The first consists entirely of coarse crystalline fossil lime, in beds 30 to 60 em thick. The formation is very resistant to erosion, forming small peaks and huge benches. Many of the limestone peaks of Fatu type are made of this formation. The total thickness is about 300 m in the areas of Tilomar, Mindelo, and Foho Luli, but the formation is not usually as thick as this. The beds are often steeply tilted, following the slopes of the underlying igneous rocks. Most of the limestones are built up entirely of crinoid stem members, other fossils being embedded in these.
These second type consists of fossiliferous red calcareous shale, the shales alternating with beds of the first type 1).
The relationship between this formation and the younger Mesozoic formations is not clear 2).
The formation is very prolific in fossils in Fronteira, particularly well preserved fossils being found in the shales.
The fossils found in this formation include crinoids, Feneste/la, Product us, Rhynchone/la, Acanthocladia, Zaphrentis and many primitive forms of ammonites. Although no determination was made of the species, the collection is strongly suggestive of the Permian."
Mesozoic in Portuguese Timor.
The dominating rocks are shales and sandstones in a flysch-facies, which can probably be correlated with the Triassic flysch of the Netherlands part of Timor. But no Triassic fossils have been found in Portuguese Timor. Basic eruptive rocks occur, similar to those found in association with the upper-paleozoic rocks. In the flysch facies no basic rocks occur, but they are found clearly intrusive into the (Triassic)
flysch, in which case they are obviously younger. Jurassic has not been determined by fossil evidence. Cretaceous has a rather wide distribution, occurring as shales and limestones with Globotruncana.
According to an information from the "Bataafsche Petroleum Maatschappij" (B.P.M.), the Triassic does not occur in the Fatu-facies in eastern Timor. Massive limestones which have the appearance of Fatu-limestones, are of Upper-Cretaceous age and part of them might even belong to the Tertiary "e", according to the smaller Foraminifera. It depends on the range of the concerning smaller Foraminifera whether these limestones are to be considered as T.e or older.
The data on the pre-tertiary stratigraphy of Portuguese Timor are too scant to allow a strict correlation with the units distinguished in the Netherlands portion of the island.
B.5.6. MESOZOIC OF PAPUA
ZWIERZYCKI (1928, p. 266), says that the Triassic has not been stated in New Guinea, but that it may be present in the series of geosynclinal deposits of the Snow Mountain Range.
On the other hand, the Jurassic and Cretaceous have a wide distribution.
The Jurassic occurs in the clay-shale facies with geodes, like we have met already in the Sula Islands and Obi. It can be compared with the Spiti shales of India. In this facies occur the Bajocian, Callovian, Oxfordian, and the transitional layers of the J urasso-Cretaceous.
From the southern slope of the Snow Mountains the following rock types with Jurassic fossils are known: Phyllitic slates with Coeloceras moermani KRUIZ.; black limestone with ? Coeloceras and canaliculate Belemnites; finegrained sandstone with ? Macrocephalites, Belemnites, and Inoceramus; siliceous shale with ? Quenstedticeras and Inoceramus.
STANLEY (1924), mentions from the Strickland River in Papua (about 7° Southern lat.) Upper Oolites with Stephanoceras blagdeni, St. lamellosum, Ammonites lingulatus, Macrocephalites and Erymnoceras.
In the October River (Mandated Territory) fragments of pyritous shale were picked up, containing a Mesozoic fauna, Belemnites, Inoceramus, Macrocephalites and Phylloceras have been reported, which are stated to correspond with the Jurassic strata of the Moluccas (STANLEY, 1923, p. 31).
The Lower Cretaceous occurs also in the clay-shale facies with geodes. In the Vogelkop a fragment of Hoplites has been found.
The Upper Cretaceous probably follows conformly upon the Jurassic-Cretaceous and contains a una of typical upper-cretaceous genera of Forammifera.
It is represented at the junction of the Fly- and Palmer Rivers in Papua, where it consists of cherts ntaining Actinaris sumatraensis (STANLEY, 1924, p. 25). ERNI (1944), described a cenomanian ammonite, Cunningtoniceras holkten n. sp., from the Wahgi Valley in the Mandated Territory.
In the Port Moresby area, a typical geosynclinal series is found, characterized by the serpentine- chert association. It contains upper-cretaceous Foraminifera and seems to pass without a break into the Lower Tertiary. More inland isolated outcrops occur of typical "Couches Rouges" with Globotruncana.
VAN THIEL wrote a report for the "Nederlandsche Nieuw Guinea Petroleum Maatschappij", dated September 1940, in which the results have been summarized of the geological reconnaissances in the concession during the period 1934-1940. From this report the following paragraphs on the Mesozoic stratigraphy are quoted with the permission of this company: .
"The three divisions of the Mesozoic in common use are:
Middle and Lower Mesozoic
Middle and Lower Mesozoic
Middle and lower Mesozoic rocks occur widely in the Mimika and Otakwa-Akimeugah areas, where they are conformable beneath the Jurasso-Cretaceous. They are composed of conglomerates, quartzites, sandstones, clays, sandy clays and sandy slates. The middle Tuaba Formation of the Mimika area is calcareous. Some of the sandy marls and sandy limestones of the higher part of this formation are rich in fossils, but unfortunately they are too poorly preserved for identification.
In the Muturi area the thinly laminated tuffaceous shales of the Basal Series, exposed on the Island of Rumberpon, are considered to belong to the Middle and Lower Mesozoic. They are unconformably overlain by the well developed Jurasso-Cretaceous of that area.
Along the northern coast of New Guinea the oldest rocks are rather highly metamorphosed. They are the Black Phyllite-Quartzite Series of Manokwari, the Korido Schists of Biak and Supiori, the Rosburi Schists of the Island of Japen and the crystalline schists of the Warenai area. The oldest rocks of proven age in the Warenai area are Jurasso-Cretaceous, but their field relations with the crystalline rocks could not be established. The highly metamorphosed rocks mentioned above may be either Lower and Middle Mesozoic or Paleozoic in age.
Jurasso-Cretaceous rocks were first distinguished in the Muturi area, and they have been found in scattered exposures over most of the concession.
Typically, they consist of clay shales, mudstones, slates, sandy shales, sandstones, and quartzites. Sometimes they are calcareous, and even sandy limestones have been recorded. In the Vogelkop the Jurasso-cretaceous rocks are dark in colour.
Along the northern coast of New Guinea igneous rocks appear to be important. The Auwewa Series of the Warenai area, considered to be of Jurasso-cretaceous age, is a sedimentary series of shales, siliceous slates, and conglomeratic sandstones, containing many porphyries, porphyrites, diabases and volcanic breccias. These are concentrated in the lower part of the series. They do not penetrate the overlying Diewewa conglomerates of supposed cretaceous age. Further, pebbles of porphyritic igneous rocks are common in these conglomerates, thus fixing the age of the igneous activity as Jurasso-Cretaceous.
The Prafi Series of Manokwari with its andesitic tuffs and basalts, and the Tuff-basalt Series of Biak and Supiori were placed by the geologists of the reconnaissance surveys in the Lower Tertiary. In view of the igneous activity found in the Jurasso-Cretaceous of the Warenai area, the Prafi Series and the Tuff-basalt Series have now been provisionally included in that formation.
The micro-fauna of the Jurasso-cretaceous rocks is poor but rather distinctive. It consists principally of arenaceous forms. Belemnites and Ammonites have been found in the Muturi area, and fragments of small Ammonites and Pentacrinus in the Akimeugah area.
Upper-cretaceous rocks are known from many areas of the Vogelkop, Bombarai, and the South coast. They appear to lie conformably on the Jurasso-Cretaceous in most localities. Their principal components are clays, shales and sandy clays, all sometimes calcareous, argillaceous limestones, massive limestones, sandstones and calcareous sandstones.
Many upper-cretaceous samples, in particular the calcareous clays, contain a rich micro-fauna. Their age is well established by frequent occurrence of several typical upper-cretaceous Foraminifera. The more common of these are: Bolivinoides, Eouvigerina, Globotruncana, Guembelina, Planoglobulina, Pseudotextularia, and Rzehakina. In the Upper Cretaceous of the Sebjar area, Belemnites and Inoceramus were discovered.
The Diewewa conglomerates of the Warenai-Waipoga area on the North coast are believed to be of upper- cretaceous age. There is slight paleontological evidence that they belong to the Mesozoic and they are unconformably on the Auwewa Series. The top beds of the latter contain Globigerina and so cannot be older than Cretaceous. No other upper-cretaceous rocks are known from the northern coast of New Guinea."
It appears from this information that part of the rocks which have been assigned to the crystalline schists by previous authors (ZWIERZYCKY, 1928, 1932) are placed in the Lower- and Middle Mesozoic by the geologists of the N.N.G.P.M.
In Rumberpon (Geelvink Bay) an unconformity occurs between this problematical Lower, and Middle Mesozoic and well developed Jurasso- Cretaceous.
In the North-coast belt another unconformity occurs between the Jurasso-cretaceous Auwewa Series and the upper-cretaceous Diewewa conglomerates. However, elsewhere the Jurasso-cretaceous sediments are conformably succeeded by the upper- cretaceous deposits.
Moreover, the Lower- and Middle Mesozoic as well as the Jurasso-Cretaceous around the Geelvink Bay appear to have a volcanic facies, which has as yet not been recorded in the zone of the Central Ranges.
B.5.7. THE BOUNDARY BETWEEN PRE-TERTIARY AND TERTIARY
The Lower Tertiary of the Indian Archipelago is generally separated from the Pre-Tertiary by a sharp unconformity. In localities where later diastrophism caused intensive dynamo-metamorphism the distinction between the Lower Tertiary and the Pre- Tertiary may be difficult to distinguish. For instance, in the Embaluh complex of NW-Borneo, TER BRUGGEN (1935) found Eocene in phyllitic facies, and this author supposes that also the Kaal Formation in the Philippines is partly of paleogene age. But in NW-Borneo an unconformity between the Pre-Tertiary and the Lower Tertiary is quite probable.
Similar conditions are encountered in the Tinombo Formation of NW-Celebes.
In the East arm of Celebes, HOPPER (N.P.P.M. report May 23, 1941) found only a disconformity between the Eocene and the Cretaceous. The same may be true for the East arm of Halmaheira, where the Cretaceous and Eocene rocks are in some instances very similar in lithological appearance, according to BROUWER" (1923 a).
In Ceram there occurs the only sequence where the Cretaceous is overlain by the Eocene defintely without a stratigraphic break. GERMERAAD (1946, p. 29), discussing Central Ceram, writes in this connection:
"For so far red limestones, marls and shales also occur in the Eogene, the red Upper-Cretaceous probably passes imperceptibly into the red Eogene, characterized by the occurrence of very big Globigerina, which seem to be Globigerina eoeaena GUEMBEL. This red Eogene in its turn passes imperceptibly via multi-coloured Eogene into green-yellow-gray marls and shales, also characterized by Globigerina eoeaena GUEMBEL, some Hantkenina (with tangentially placed peripheral spines, therefore Middle- or Yeung-Eocene according to M.REY, Bull. Soc. Geol. France, 5, 8, 1938, pp. 321-340) and Guembelina; besides small Globigerina (probably not G. erefaeea) together with big forms. It seems very probable, that all these gray marls and shales may be regarded as Eocene. From the field-annotations and the samples we get the impression, that we have to do with a continuous sedimentation of Upper-Cretaceous up to and including Eocene. It may be that a part of the red limestones, marls, and shales belong to the transitional layers, which sometimes also contain big Globigerina."
Besides this Eocene in a bathyal facies, which lies with a gradational contact upon the bathyal Upper-Cretaceous, also Eocene in a littoral fades occurs in Central Ceram. Whereas the former facies is dynamo-metamorphic by orogenesis, the latter is not altered. In West Ceram also a gradational transition of the Cretaceous into the Lower Tertiary seems to occur (the red or variegated sandy Globigerina- marls, which resemble the "Couches Rouges" of the European Alps). A boulder of (upper?) eocene conglomerate with (?) Discocyclina was found (VALK, 1945, p. 16-17) which represents the Eocene in littoral facies.
In East Ceram, VAN DER SLUIS (1947) mentions two hard marls in the inlier of Nief. The first contains a fauna of small Foraminifera with 25 species, a number of which occur elsewhere in the Eocene, whilst other are known from the Oligocene. The age is possibly Upper Eocene. The second contains 14 species of small Foraminifera, a part of which is known from the Eocene; the occurrence of Lenticulina velascoensis, Globorotalia aragonensis and Bolivinoides sp. points to a transition between Cretaceous and Tertiary. These marls are probably conformably underlain by Globotruncana-limestones.
For two regions, viz. in the SW part of Central Celebes and in J amdena, the literature mentions an apparently conformable sequence of cretaceous and eocene formations.
In the SW part of Central Celebes, the regional metamorphic pre-tertiary rocks, exposed in the core of the LatimodjongRange, are overlain at the flanks by the "Maroro Formation". The latter is some thousands of metres thick, consisting of violet, red and grey shales, often globigerina-bearing and sometimes with pyrite and chalcopyrite impregnations. On account of these chalcopyrites the formation has also been called (somewhat misleadingly) the "Coppershale Formation" by DE KONING KNIJFF (1914) and REYZER (1920).
The formation contains intercalations of sandstone, calcareous sandstone and limestone. The limestone contains in the lower horizons Camerina, Assilina, Alveolina s.str., and Discocyclina, thus typical eocene fossils; a higher horizon of the section, containing Heterostegina, Cycloc/ypeus and Amphistegina, was dated as Aquitanian by DOLLFUS (1917) without coercive paleontological reason.
ABENDANON (1915/1918) accepted a young cretaceous age for the Maroro Formation, without adequate paleontological grounds, which passes conformably into the Eocene, whilst the above mentioned eocene limestones are separated from the other sediments by faults. The latter opinion was energetically impugned by REYZER; but this author still maintained a cretaceous age for the deeper parts of the Maroro Formation on account of an imprint of an ammonite found in a black shale of the "volcanic formation", which is held by him (at least partly) for the equivalent of the Maroro Series. REYZER is even of the opinion that the conformable sequence ends in the Pliocene.
BROUWER and HETZEL found in this Maroro Formation intercalations of harder phyllitic shales, radiolarian cherts and breccious limestones. The letter contain Orbitolina and Astrarea cf. eolumel/ata OPPENH, which points to Upper Cretaceous.
RUTTEN (1927, p. 621-623) pointed out that the supposed conformity between the Cretaceous and the Eocene is yet by no means proved, and the stratigraphical, facies- and tectonical relations of rocks in this region are still to be proved. See further table 98 in Chapter V.
Jamdena (Tanimber Islands).
Fr. WEBER provided some new informations on the Eocene of this island which were published by UMBGROVE (1934, p. 27-29). In the NW part of the island some littoral deposits occur, containing detritus of Mesozoic rocks, and eocene key-fossils (small Camerinae, Assilina, Alveolina, Discocyclina, Lacazinat. These sediments are closely related with cretaceous Globigerina-rocks. BADINGS 1936, p. 281) called the position of the eocene deposits upon the Cretaceous "probably pseudoconformable", mentioning WEBER as the source of this opinion. But WEBER speaks only of an "apparent conformity", so that possibly an unconformable or disconformable position was oeant by the latter.
The unconformity or disconformity at the base of the Tertiary, when the sea transgressed over the pre-tertiary land, has been found in numerous places all over the Indian Archipelago. Moreover, the Lower Tertiary has almost exclusively a littoral or neritic facies. At the beginning of the Tertiary a vast land mass extended in the area of the Indian Archipelago, forming a land bridge between the Asiatic and the Australian Continent. Only in Central Ceram, and perhaps in some other areas between the Sunda Land and the Sahul Land, marine conditions have persisted from the Cretaceous into lower-tertiary time.
1) WANNER compares one of his forms with "Monotis salinaria" from Borneo, described by VOGEL (Samml. des Geol. Reichs-Museurns in Leiden, 1904, 1, 7, p. 218). But VOGEL adds a characteristic feature to the original description of BRONN, thus indicating that this species from Borneo is at most a variety of the original Monotis salinaria BR. t) The Volumes I-IV are edited in 1940-42 by the Geol. Expedition to the Lesser Sunda Islands under the leadership of H. A. BROUWER. The above mentioned papers appeared partly separately as doctoral theses at the University of Amsterdam, being later on united to these four volumes.