DEVELOPMENT OF THE TERTIARY OFFSHORE PAPUAN BASIN

1975 ◽  
Vol 15 (1) ◽  
pp. 55 ◽  
Author(s):  
N. C. Tallis
Keyword(s):  
Late Eocene ◽  
Early Miocene ◽  
Second Phase ◽  
The West ◽  
Fine Grained ◽  
Early Oligocene ◽  
Coral Sea ◽  
Clastic Sediments ◽  
Marine Seismic ◽  
Rigid Segment

Marine seismic studies combined with wildcat drilling in the Gulf of Papua have provided a comprehensive insight into the geology of the offshore Papuan Basin. The Basin adjoins a downwarped but structurally rigid segment of the Australian continental shield in the west, and the Coral Sea Basin in the southeast. It incorporates arcuate geosynclinal development eastward and northward beyond the continental margin. The pre-Tertiary history is relatively obscure. Jurassic-Lower Cretaceous clastic sediments overlie granites and volcanics of the continental shield in the west. Eastward, the record is masked by great thicknesses of Tertiary strata, and the pre-Tertiary may be represented in outcrop by a metamorphic series of indeterminate age.The Tertiary offshore basin developed in three distinct phases, commencing in Late Cretaceous/Early Eocene time, when seas transgressed from east to west across a peneplaned surface. An eastward-thickening wedge of argillaceous limestones and cherts was deposited. Regression and erosion occurred in Late Eocene/Early Oligocene time, possibly in association with upwarp of the oceanic crust, which created an eastern volcanic borderland. Typical orthogeosynclinal sedimentation followed in Early Miocene time, with reef, shoal and pelagic limestones deposited marginal to the stable western (continental) shelf, and with prolific volcanism associated with the eastern (oceanic) flank. This volcanism was the source for a thick pile of mudstone-greywacke sediments which was deposited in an intermediate eugeosyncline.This second phase was modified in Late Miocene time by regional uplift, and by development of the Central Mountain geanticlinal belt. This created an immense southeasterly pro-grading system which rapidly buried the Early Miocene profile. These fine grained clastic Plio-Pleistocene sediments have been highly deformed by gravitational and diapiric influences in the east-central portion of the basin. Huge volumes of sediment are still being transported southeastward into the Coral Sea Basin.

scholarly journals Paleogene extension in the Northern Aegean: Colluvial/debris flow deposits of the Early-Middle Eocene in NW Thrace Basin, Turkey

2021 ◽  
Vol 72 (3) ◽  
Author(s):  
Serdar Akgündüz ◽  
Hayrettin Koral
Keyword(s):  
Debris Flow ◽  
Fault Zone ◽  
Middle Eocene ◽  
Late Eocene ◽  
Coarse Grained ◽  
Fine Grained ◽  
Metasedimentary Rocks ◽  
Early Oligocene ◽  
Thrace Basin ◽  
Nw Turkey

The Thrace Basin consists of Paleogene–Neogene deposits that lie in the lowland south of the Strandja highlands in NW Turkey, where metagranitic and metasedimentary rocks occur. The Akalan Formation consisting of colluvial fan/debris flow deposits represents the base of the sequence in the northern Thrace basin where it is bounded by a right lateral strike-slip oblique fault called “The Western Strandja Fault Zone”. This formation exhibits a coarse-grained, angular and grain-supported character close to the fault zone which has releasing-bends. Fine-grained, rounded, and matrix-supported sediments occur away from the contact. During this study, the Akalan Formation is described for the first time as having larger benthic foraminifera (LBF) of Coskinolina sp of Ypresian–Lutetian, Nummulites obesus of early Lutetian, Dictyoconus egyptiensis of Lutetian, Orbitolites sp. of Ypresian–Bartonian, Miliola sp of early–middle Eocene, Idalina grelaudae of early Lutetian–Priabonian, Ammobaculites agglutinans, Amphimorphina crassa, Dentalina sp., Nodosaria sp., Operculina sp., Lenticulina sp., Quinqueloculina sp. and Amphistegina sp. of Eocene. This unit passes upward with a conformity into reefal limestones of the middle/late Eocene–early Oligocene Soğucak Formation. At times, the limestone overlies the conformity, there is an indication of a prograding sedimentary sequence. The new stratigraphic, paleontological, sedimentological and structural findings related to the NW Thrace Basin suggest a strong transtensional/extensional tectonic control for the initial Paleogene sedimentary deposition during the Ypresian–Lutetian period as shown by fossil content of the Akalan Formation. Right lateral-slip extensional tectonics appears to have had activity during the middle–late Eocene transgressive deposition of the Soğucak Formation when the basin became deepened and enlarged.

Late Eocene – Early Miocene facies and stratigraphic development, Taranaki Basin, New Zealand: the transition to plate boundary tectonics during regional transgression

2019 ◽  
Vol 156 (10) ◽  
pp. 1751-1770 ◽  
Author(s):  
Dominic P. Strogen ◽  
Karen E. Higgs ◽  
Angela G. Griffin ◽  
Hugh E. G. Morgans
Keyword(s):  
New Zealand ◽  
Tectonic Setting ◽  
Plate Boundary ◽  
Late Eocene ◽  
Early Miocene ◽  
Fault System ◽  
Initial Development ◽  
Early Oligocene ◽  
Well Data ◽  
Latest Eocene

AbstractEight latest Eocene to earliest Miocene stratigraphic surfaces have been identified in petroleum well data from the Taranaki Basin, New Zealand. These surfaces define seven regional sedimentary packages, of variable thickness and lithofacies, forming a mixed siliciclastic–carbonate system. The evolving tectonic setting, particularly the initial development of the Australian–Pacific convergent margin, controlled geographic, stratigraphic and facies variability. This tectonic signal overprinted a regional transgressive trend that culminated in latest Oligocene times. The earliest influence of active compressional tectonics is reflected in the preservation of latest Eocene – Early Oligocene deepwater sediments in the northern Taranaki Basin. Thickness patterns for all mid Oligocene units onwards show a shift in sedimentation to the eastern Taranaki Basin, controlled by reverse movement on the Taranaki Fault System. This resulted in the deposition of a thick sedimentary wedge, initially of coarse clastic sediments, later carbonate dominated, in the foredeep close to the fault. In contrast, Oligocene active normal faulting in a small sub-basin in the south may represent the most northerly evidence for rifting in southern Zealandia, related to Emerald Basin formation. The Early Miocene period saw a return to clastic-dominated deposition, the onset of regional regression and the southward propagation of compressional tectonics.

Geochemical constraints on Eocene–Miocene geodynamic and magmatic evolution of the Varan-Naragh area, Urumieh-Dokhtar Magmatic Arc, Iran

2020 ◽  
Vol 57 (9) ◽  
pp. 1048-1065
Author(s):  
Ghosoun Zheira ◽  
Fariborz Masoudi ◽  
Bahman Rahimzadeh
Keyword(s):  
Rare Earth ◽  
Lithospheric Mantle ◽  
Active Continental Margin ◽  
Volcanic Rocks ◽  
Late Eocene ◽  
Early Miocene ◽  
Temporal Association ◽  
Second Phase ◽  
Isotopic Ratios ◽  
Magmatic Arc

Two different types of igneous rock formed during separate Cenozoic magmatic phases in the Varan-Naragh area in the central part of the Urumieh-Dokhtar Magmatic Arc (UDMA) of Iran as a part of the Alpine-Himalayan system. The first phase comprises late Eocene – early Oligocene Naragh gabbroic rocks (Ns), and the second phase is characterized by the emplacement of both volcanic and plutonic rocks of the early Miocene. Both phases display moderate enrichment of large rare earth elements and depletion of high field strength elements coupled with negative Nb, Ti, and P anomalies, indicative of subduction-related magmatic events within an active continental margin. Initial values of 87Sr/86Sr and εNdT are 0.70684 and +0.15 and 0.70560–0.70654 and +2.55 to +3.49 for Ns and early Miocene intrusive and volcanic rocks, respectively. Comparisons of rare earth element patterns and mantle-like isotopic ratios suggest that Ns mafic and early Miocene magmatic rocks were derived from partial melting of a common subcontinental lithospheric mantle. Geochemical and isotopic ratios of Ns gabbroic rocks, in combination with the data related to other coeval and proximal mafic-intermediate intrusions (such as Nashalj), suggest enrichment of the lithospheric mantle by slab-derived fluids with a minor subducted sediment melt. The low εNdT of Ns gabbroic rocks can reflect involvement of slab-derived components. The geochemical similarity and the close spatial and temporal association of Varan intrusive and volcanic rocks suggest a common petrogenetic relationship. Geochemical, isotopic, and geochronological evidence from the region indicate three major phases of igneous activity in the Kashan magmatic segment of the central UDMA during late Eocene to Miocene, resulting in complex tectonic regime transition from compressional subduction to extensional post-collisional settings. Integrated with published studies, the new results support a model suggesting that subduction-related magmatic activity was still influencing the central UDMA in the early Miocene time and are also consistent with the notion of oblique and diachronous collision along the northeast margin of the Arabia plate.

The Thrace Basin and the Black Sea: the Eocene–Oligocene marine connection

2017 ◽  
Vol 156 (1) ◽  
pp. 39-61 ◽  
Author(s):  
ARAL I. OKAY ◽  
ERCAN ÖZCAN ◽  
AYNUR HAKYEMEZ ◽  
MUZAFFER SIYAKO ◽  
GÜRSEL SUNAL ◽  
...  
Keyword(s):  
Black Sea ◽  
Late Cretaceous ◽  
Damage Zone ◽  
Late Eocene ◽  
Upper Eocene ◽  
The West ◽  
Clastic Sediment ◽  
Early Oligocene ◽  
Thrace Basin ◽  
West Black Sea

AbstractThe Late Cretaceous – Recent West Black Sea Basin and the Eocene–Oligocene Thrace Basin are separated by the Strandja arch comprising metamorphic and magmatic rocks. Since Late Cretaceous time the Strandja arch formed a palaeo-high separating the two basins which accumulated clastic sediment of >9 km thickness. During late Eocene – early Oligocene time the marine connection between these basins existed through the Çatalca gap west of Istanbul. The Çatalca gap lies on the damage zone of a major Cretaceous strike-slip fault; it formed a 15 km wide marine gateway, where carbonate-rich sediments of thicknessc.350 m were deposited. The sequence consists of upper Eocene shallow marine limestones (SBZ18-20) overlain by upper Eocene – lower Oligocene (P16-P19 zones) pelagic marl with a rich fauna of planktonic foraminifera; the marls are intercalated with 31–32 Ma acidic tuff and calc-arenite beds. The Çatalca gap is bounded in the west by a major normal fault, which marks the eastern boundary of the Thrace Basin. Seismic reflection profiles, well data and zircon U–Pb ages indicate that the Thrace Basin sequence west of the fault is late Eocene – middle Oligocene (37–27 Ma) in age and that the fault has accommodated 2 km of subsidence. Although there was a marine connection between the West Black Sea and Thrace basins during late Eocene – early Oligocene time, no significant exchange of clastic sediment took place. Sedimentation in the Çatalca gap ended abruptly during early Oligocene time by uplift, and this eventually led to the paralic conditions in the Thrace Basin.

scholarly journals Anatomy of the Nasal and Auditory Regions of the Fossil Lagomorph Palaeolagus haydeni: Systematic and Evolutionary Implications

2021 ◽  
Vol 9 ◽  
Author(s):  
Irina Ruf ◽  
Jin Meng ◽  
Łucja Fostowicz-Frelik
Keyword(s):  
Computed Tomography ◽  
Middle Ear ◽  
North American ◽  
Late Eocene ◽  
Early Miocene ◽  
Thin Wall ◽  
Micro Computed Tomography ◽  
3D Reconstructions ◽  
Early Oligocene ◽  
Ontogenetic Stages

Palaeolagus, a late Eocene to early Miocene North American lagomorph genus, represented by numerous and well-preserved specimens, has been long considered a basal leporid, although it is currently understood as a stem lagomorph. Based on micro-computed tomography (μCT) data and 3D reconstructions, here we present the first description of intracranial structures of the nasal and auditory regions of a complete skull of Palaeolagus haydeni from the early Oligocene of Nebraska. Although Palaeolagus haydeni shows a puzzling mixture of extant leporid and ochotonid characters, it helps to polarize and re-evaluate already known lagomorph intracranial characters based on outgroup comparison with Rodentia and Scandentia. Common derived features of Palaeolagus haydeni and extant Lagomorpha are the dendritic maxilloturbinal and the excavated nasoturbinal that contacts the lamina semicircularis. Generally, Palaeolagus haydeni and Leporidae have several characters in common, some of which are certainly plesiomorphic (e.g., thin wall of bulla tympani and flat conic cochlea). Palaeolagus haydeni resembles Leporidae in having an interturbinal between the two frontoturbinals, and three ethmoturbinals plus one interturbinal between ethmoturbinal I and II. Now, this should also be regarded as a plesiomorphic grundplan pattern for Leporidae whereas ochotonids are derived from the lagomorph grundplan as concerns the number of frontoturbinals. Concerning the middle ear, Palaeolagus haydeni significantly contributes to the polarization of the anterior anchoring of the malleus in extant lagomorphs. Palaeolagus haydeni resembles the pattern observed in early ontogenetic stages of Ochotonidae, i.e., the attachment of the malleus to the ectotympanic via a short processus anterior. The patterns in adult ochotonids and leporids now can be regarded as two different and apomorphic character states. Autapomorphic characters of Palaeolagus haydeni are the reduced frontoturbinal 2 and the additional anterolaterally oriented process of the lamina semicircularis. Interestingly, among the investigated intracranial structures the loss of the secondary crus commune is the only apomorphic grundplan character of crown Lagomorpha.

scholarly journals Late Eocene–early Miocene evolution of the southern Australian subtropical front: a marine palynological approach

2021 ◽  
Vol 40 (2) ◽  
pp. 175-193
Author(s):  
Frida S. Hoem ◽  
Isabel Sauermilch ◽  
Suning Hou ◽  
Henk Brinkhuis ◽  
Francesca Sangiorgi ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Late Eocene ◽  
Early Miocene ◽  
Ocean Drilling Program ◽  
Subtropical Front ◽  
Leeuwin Current ◽  
Ocean Drilling ◽  
Early Oligocene ◽  
Integrated Ocean Drilling Program ◽  
Oceanographic Conditions

Abstract. Improvements in our capability to reconstruct ancient surface-ocean conditions based on organic-walled dinoflagellate cyst (dinocyst) assemblages from the Southern Ocean provide an opportunity to better establish past position, strength and oceanography of the subtropical front (STF). Here, we aim to reconstruct the late Eocene to early Miocene (37–20 Ma) depositional and palaeoceanographic history of the STF in the context of the evolving Tasmanian Gateway as well as the potential influence of Antarctic circumpolar flow and intense waxing and waning of ice. We approach this by combining information from seismic lines (revisiting existing data and generating new marine palynological data from Ocean Drilling Program (ODP) Hole 1168A) in the western Tasmanian continental slope. We apply improved taxonomic insights and palaeoecological models to reconstruct the sea surface palaeoenvironmental evolution. Late Eocene–early Oligocene (37–30.5 Ma) assemblages show a progressive transition from dominant terrestrial palynomorphs and inner-neritic dinocyst taxa as well as cysts produced by heterotrophic dinoflagellates to predominantly outer-neritic/oceanic autotrophic taxa. This transition reflects the progressive deepening of the western Tasmanian continental margin, an interpretation supported by our new seismic investigations. The dominance of autotrophic species like Spiniferites spp. and Operculodinium spp. reflects relatively oligotrophic conditions, like those of regions north of the modern-day STF. The increased abundance in the earliest Miocene of Nematosphaeropsis labyrinthus, typical for modern subantarctic zone (frontal) conditions, indicates a cooling and/or closer proximity of the STF to the site . The absence of major shifts in dinocyst assemblages contrasts with other records in the region and suggests that small changes in surface oceanographic conditions occurred during the Oligocene. Despite the relatively southerly (63–55∘ S) location of Site 1168, the rather stable oceanographic conditions reflect the continued influence of the proto-Leeuwin Current along the southern Australian coast as Australia continued to drift northward. The relatively “warm” dinocyst assemblages at ODP Site 1168, compared with the cold assemblages at Antarctic Integrated Ocean Drilling Program (IODP) Site U1356, testify to the establishment of a pronounced latitudinal temperature gradient in the Oligocene Southern Ocean.

New turtles (Chelonia) from the late Eocene through late Miocene of the Panama Canal Basin

2012 ◽  
Vol 86 (3) ◽  
pp. 539-557 ◽  
Author(s):  
Edwin Cadena ◽  
Jason R. Bourque ◽  
Aldo F. Rincon ◽  
Jonathan I. Bloch ◽  
Carlos A. Jaramillo ◽  
...  
Keyword(s):  
Late Miocene ◽  
Late Eocene ◽  
Panama Canal ◽  
Early Miocene ◽  
South American ◽  
Early Oligocene ◽  
Isthmus Of Panama ◽  
Early Arrival ◽  
The Tropics ◽  
First Contact

Four distinct fossil turtle assemblages (Chelonia) are recognized from the Panama Canal Basin. The oldest, from the late Eocene–early Oligocene Gatuncillo Formation, is dominated by podocnemidid pleurodires. The early Miocene Culebra Formation includes both podocnemidids and trionychids. The early to middle Miocene Cucaracha Formation includes taxa classified in Geoemydidae (including Rhinoclemmys panamaensis n. sp.), Kinosternidae (represented by Staurotypus moschus n. sp.), large testudinids, trionychids, and podocnemidids, and finally, the late Miocene Gatun Formation records cheloniid sea turtles. These fossils include the oldest known representatives of Rhinoclemmys, the oldest record of kinosternids in Central America with a more extensive southern paleodistribution for Staurotypus and staurotypines in general, early occurrences of giant tortoises in the Neotropics, the oldest occurrence of soft-shell turtles in the tropics, the oldest late Eocene–early Oligocene Neotropical occurrences of podocnemidids. The Panamanian fossil turtles represent clades that are primarily endemic to North America, showing their very early arrival into the Neotropics prior to the complete emergence of the Isthmus of Panama, as well as their first contact with Caribbean-South American pleurodires by the early Miocene.

scholarly journals Kinematic analysis and tertiary evolution of the Lesvos ophiolites and metamorphic sole (Aegean sea, Greece)

2001 ◽  
Vol 34 (1) ◽  
pp. 267 ◽  
Author(s):  
D. MOUNTRAKIS ◽  
E. THOMAIDOU ◽  
N. ZOUROS ◽  
A. KILIAS
Keyword(s):  
Continental Margin ◽  
Aegean Sea ◽  
Late Eocene ◽  
Early Miocene ◽  
Tectonic Event ◽  
Detachment Faults ◽  
Early Oligocene ◽  
Tectonic Events ◽  
Extensional Tectonic ◽  
Thrust Sheets

In Lesvos Island, the ophiolites and the metamorphic sole are emplaced onto the Permo-Triassic continental margin rocks. New field data on the Tertiary kinematics distinguished three successive tectonic events that affected the Lesvos ophiolites and sole. The Dl compressional event took place in Late Eocene - Early Oligocene and produced several thrust sheets and their stacking over the continental margin. The thickening of the crust after the Dl event, was followed by an important extensional tectonic event (D2) in semi-ductile conditions in Oligocene-Early Miocene times, which produced the uplift process of the orogen and the lateral rejection of the tectonic nappes through large extensional semi-ductile faults of low angle (detachment faults) and caused the exhumation of the underlying continental margin rocks in the form of a tectonic window. This extensional tectonic event led to the thinning of the crust in the wider area of Lesvos and probably caused the Early Miocene volcanic activity. The last D3 extensional tectonic event, took place in brittle conditions and represents the neotectonic regime in Late Miocene-Recent times.

Middle Eocene through Early Miocene North American Vegetational History: 50-16.3 Ma

1999 ◽  
Author(s):  
Alan Graham
Keyword(s):  
Sierra Nevada ◽  
Rocky Mountains ◽  
Middle Eocene ◽  
Co2 Concentration ◽  
Late Eocene ◽  
Early Miocene ◽  
Northern Rocky Mountains ◽  
Atmospheric Circulation Patterns ◽  
Early Oligocene ◽  
Latest Eocene

During the Middle Eocene through the Early Miocene, erosion of the Appalachian Mountains exceeded uplift and there was a net reduction in elevation. In the Rocky Mountains uplift continued through the Middle Eocene (end of the Laramide orogeny), waned in the Middle Tertiary, and then increased beginning at about 10 Ma. Earlier reconstructions placed paleoelevations in the Rocky Mountains during the Middle Eocene through the Early Miocene at approximately half the present relief. The maximum elevation in the Front Ranges during the latest Eocene was estimated at ~2500 m (~8000 ft; MacGinitie, 1953). Recent approximations are for nearly modern elevations in several areas by the Eocene-Oligocene. Extensive Eocene volcanism deposited ash and blocked drainage systems, augmenting uplift and facilitating the preservation of extensive fossil floras and faunas. In the far west the beginning of Tertiary volcanism in the Sierra Nevada is dated at ~ 33 Ma near the Eocene-Oligocene boundary. A drying trend becomes evident in the Middle Eocene and reduced moisture, along with the waning of volcanic activity in the Oligocene, restricted conditions favorable to fossilization. The number of Oligocene floras in the northern Rocky Mountains is considerably fewer than in younger deposits to the west. In the absence of extensive plate reorganization and orogeny, CO2 concentration decreased, which contributed to a temperature decline that continued through the Cenozoic and intensified in the Late Tertiary. Recall from Chapter 2 (sections on orogeny and volcanism) that uplift plays a role in determining long-term climate by creating rainshadows, altering atmospheric circulation patterns, and increasing the erosion of silicate rocks that causes a drawdown of CO2. This allows heat to escape from the troposphere and results in lower temperatures. Marine benthic temperatures were ~10°C in the early Late Eocene and ~2°C near the Eocene-Oligocene boundary, assuming an essentially ice-free Earth during that time, and increased to ~5-6°Cnear the end of the Early Miocene. Temperatures over land in the midnorthern latitudes are estimated to have dropped by ~12°C between the Late Eocene and Early Oligocene (Wolfe, 1992a).

West coast North America record of the Paleogene marine stromboid gastropodRimellaand paleobiogeography of the genus

2013 ◽  
Vol 87 (5) ◽  
pp. 826-841 ◽  
Author(s):  
Richard L. Squires
Keyword(s):  
North America ◽  
West Coast ◽  
Western Europe ◽  
Middle Eocene ◽  
Late Eocene ◽  
New Combination ◽  
The West ◽  
Early Oligocene ◽  
Early Paleocene ◽  
First Time

The west coast of North America record of the shallow-marine stromboid gastropod genusRimellaAgassiz, 1841 is restudied for the first time in 90 years. This genus comprises a small group of Paleogene gastropods characterized by having an ornamented fusiform shell, a posterior canal ascending the spire, and simple (non-flared) outer lip.Rimella, whose familial ranking has been inconsistent, is placed here in family Rostellariidae Gabb, 1868, subfamily Rimellinae Stewart, 1927.EctinochilusCossmann, 1889;MacilentosClark and Palmer, 1923;VaderosClark and Palmer, 1923; andCowlitziaClark and Palmer, 1923 are recognized here as junior synonyms ofRimella. Four species are recognized from the west coast of North America: early to middle EoceneRimella macilentaWhite, 1889; early EoceneRimella oregonensisTurner, 1938; middle to late EoceneRimella supraplicata(Gabb, 1864) new combination, of whichRostellaria canaliferGabb, 1864,Cowlitizia washingtonensisClark and Palmer, 1923, andCowlitzia problematicaHanna, 1927 are recognized here as junior synonyms; and late EoceneRimella elongataWeaver, 1912.Rimellawas a warm-water gastropod whose earliest known record is of early Paleocene (Danian) age in Pakistan. Other than the west coast of North America,Rimellais found in Eocene strata in western Europe, Turkey, Egypt, Pakistan, southeastern United States, Panama, Peru, and, to a lesser degree, in Trinidad, Columbia, Java, and New Zealand. Global cooling near the end of the Eocene greatly diminished the genus. Its youngest known occurrences are of early Oligocene age in Germany, Italy, England, and Peru.

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