Origin and genesis of Late Jurassic to Early Cretaceous granites of the North Qinling Terrane, China

Multituberculates, though among the most commonly encountered mammalian fossils of the Mesozoic, are poorly known from the North American Early Cretaceous, with only one taxon named to date. Herein we describe Argillomys marylandensis, gen. et sp. nov., from the Early Cretaceous of Maryland, based on an isolated M2. Argillomys represents the second mammal known from the Arundel Clay facies of the Patuxent Formation (Lower Cretaceous: Aptian). Though distinctive in its combination of characters (e.g., enamel ornamentation consisting of ribs and grooves only, cusp formula 2:4, presence of distinct cusp on anterobuccal ridge, enlargement of second cusp on buccal row, central position of ultimate cusp in lingual row, great relative length), the broader affinities of Argillomys cannot be established because of non-representation of the antemolar dentition. Based on lack of apomorphies commonly seen among Cimolodonta (e.g., three or more cusps present in buccal row, fusion of cusps in lingual row, cusps strongly pyramidal and separated by narrow grooves), we provisionally regard Argillomys as a multituberculate of “plagiaulacidan” grade. Intriguingly, it is comparable in certain respects to some unnamed Paulchoffatiidae, a family otherwise known from the Late Jurassic – Early Cretaceous of the Iberian Peninsula.

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Late Jurassic - Early Cretaceous paleoenvironmental evolution of the Transbaikal basins (SE Siberia): implications for the Mongol-Okhotsk orogeny

BSGF - Earth Sciences Bulletin ◽

10.1051/bsgf/2017010 ◽

2017 ◽

Vol 188 (1-2) ◽

pp. 9 ◽

Cited By ~ 7

Author(s):

Marc Jolivet ◽

Anastasia Arzhannikova ◽

Andrei Frolov ◽

Sergei Arzhannikov ◽

Natalia Kulagina ◽

...

Keyword(s):

Early Cretaceous ◽

Middle Jurassic ◽

Late Jurassic ◽

Tectonic Setting ◽

Alluvial Fan ◽

Crustal Thickening ◽

Compressive Deformation ◽

Transbaikal Region ◽

Meandering River ◽

The North

The Late Jurassic - Early Cretaceous tectonic evolution of SE Siberia was marked by the closure of the Mongol-Okhotsk ocean. While this geodynamic event led to compressive deformation and denudation in a wide area encompassing the North-Altay, Sayan and Baikal Patom ranges, it was contemporaneous to widespread extension from the Transbaikal region situated immediately north of the suture zone to the Pacific plate, affecting eastern Mongolia and northeastern China. In this study we review the paleontological and sedimentological data available in the Russian literature and provide new macro-floral and palynological data from the Mesozoic sediments of three Transbaikal basins. These data are used to describe the paleoenvironmental and paleoclimatic evolution of the Transbaikal area in order to assess the topographic evolution of the region in relation with the closure of the Mongol-Okhotsk ocean. We establish that the Transbaikal basins evolved in a continuously extensional tectonic setting from at least the Early-Middle Jurassic to the Early Cretaceous. The associated sedimentary environments are characterized by retrogradation from alluvial fan–braided river dominated systems prevailing during the Early to Middle Jurassic initial opening of the basins to meandering river– lacustrine systems that developed during the Late Jurassic - Early Cretaceous interval. No evidence of high relief topography was found and we conclude that, while compression and denudation occurred in the North Altai, Sayan and Patom ranges, in the Transbaikal region, the docking of the Mongolia-North China continent to Siberia was a “soft collision” event, possibly involving a major strike-slip displacement that did not lead to an orogenic event implying strong compressive deformation, crustal thickening and topography building.

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AN EARLY CRETACEOUS SOURCE ROCK IN THE KENDREW TERRACE, DAMPIER SUB-BASIN?

The APPEA Journal ◽

10.1071/aj95026 ◽

1996 ◽

Vol 36 (1) ◽

pp. 477 ◽

Cited By ~ 1

Author(s):

S. Ryan-Grigor ◽

C. M. Griffiths

Keyword(s):

Source Rock ◽

North Sea ◽

Early Cretaceous ◽

Late Jurassic ◽

Large Scale ◽

Free Water ◽

Organic Content ◽

Source Rocks ◽

The North ◽

Northern North Sea

The Early to Middle Cretaceous is characterised worldwide by widespread distribution of dark shales with high gamma ray readings and high organic contents defined as dark coloured mudrocks having the sedimentary, palaeoecological and geochemical characteristics associated with deposition under oxygen-deficient or oxygen-free bottom waters. Factors that contributed to the formation of the Early to Middle Cretaceous 'hot shales' are: rising sea-level, a warm equable climate which promoted water stratification, and large scale palaeogeographic features that restrict free water mixing. In the northern North Sea, the main source rock is the Late Jurassic to Early Cretaceous Kimmeridge Clay/Draupne Formation 'hot shale' which occurs within the Viking Graben, a large fault-bounded graben, in a marine environment with restricted bottom circulation and often anaerobic conditions. Opening of the basin during a major trans-gressive event resulted in flushing, and deposition of normal open marine shales above the 'hot shales'. The Late Callovian to Berriasian sediments in the Dampier Sub-basin are considered to have been deposited in restricted marine conditions below a stratified water column, in a deep narrow bay. Late Jurassic to Early Cretaceous marine sequences that have been cored on the North West Shelf are generally of moderate quality, compared to the high quality source rocks of the northern North Sea, but it should be noted that the cores are from wells on structural highs. The 'hot shales' are not very organic-rich in the northern Dampier Sub-basin and are not yet within the oil window, however seismic data show a possible reduction in velocity to the southwest in the Kendrew Terrace, suggesting that further south in the basin the shales may be within the oil window and may also be richer in organic content. In this case, they may be productive source rocks, analogous to the main source rock of the North Sea.

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Controls on the preservation of Jurassic volcanism in the Northern Carnarvon Basin

The APPEA Journal ◽

10.1071/aj20137 ◽

2021 ◽

Vol 61 (2) ◽

pp. 600

Author(s):

Michael Curtis ◽

Simon Holford ◽

Mark Bunch ◽

Nick Schofield

Keyword(s):

Early Cretaceous ◽

Late Jurassic ◽

Volcanic Centre ◽

North West ◽

The North ◽

Igneous Provinces ◽

Australian Continent ◽

Northern Carnarvon Basin ◽

Uplift And Erosion ◽

Carnarvon Basin

The Northern Carnarvon Basin (NCB) forms part of the North West Australian margin. This ‘volcanic’ rifted margin formed as Greater India rifted from the Australian continent through the Jurassic, culminating in breakup in the Early Cretaceous. Late Jurassic to Early Cretaceous syn-rift intrusive magmatism spans 45000km2 of the western Exmouth Plateau and the Exmouth Sub-basin; however, there is little evidence of associated contemporaneous volcanic activity, with isolated late Jurassic volcanic centres present in the central Exmouth Sub-basin. The scarcity of observed volcanic centres is not typical of the extrusive components expected in such igneous provinces, where intrusive:extrusive ratios are typically 2–3:1. To address this, we have investigated the processes that led to the preservation of a volcanic centre near the Pyrenees field and the Toro Volcanic Centre (TVC). The volcanic centre near the Pyrenees field appears to have been preserved from erosion associated with the basin-wide KV unconformity by fault-related downthrow. However, the TVC, which was also affected by faulting, is located closer to the focus of regional early Cretaceous uplift along the Ningaloo Arch to the south and was partly eroded. With erosion of up to 2.6km estimated across the Ningaloo Arch, which, in places, removed all Jurassic strata, we propose that the ‘Exmouth Volcanic Province’ was originally much larger, extending south from the TVC into the southern Exmouth Sub-basin prior to regional uplift and erosion, accounting for the ‘missing’ volume of extrusive igneous material in the NCB.

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Early Cretaceous (Neocomian-Cenomanian) Palynomorphs

Journal of Micropalaeontology ◽

10.1144/jm.4.1.131 ◽

1985 ◽

Vol 4 (1) ◽

pp. 131-149 ◽

Cited By ~ 43

Author(s):

B. Thusu ◽

J. G. L. A. Van Der Eem

Keyword(s):

Early Cretaceous ◽

Late Jurassic ◽

Age Determination ◽

Marine Environments ◽

Dinoflagellate Cysts ◽

Shallow Marine ◽

The North ◽

Close Proximity ◽

Pollen And Spores ◽

Early Late

Abstract. INTRODUCTIONThis study is primarily concerned with the Neocomian to Aptian palynomorphs recorded in selected exploration wells (See Fig. 9). In order to document a complete Early Cretaceous microfloral succession in the studied wells, a reconnaissance of Aptian to Early Cenomanian palynomorphs was also undertaken. Details of the results from this younger interval appear in a later section.Palynomorph assemblages vary in preservation and character. To the north, sandstone, siltstone and shale deposited in shallow-marine environments, contain well-preserved assemblages of dinoflagellate cysts, pollen and spores which can be used for stage-level age determination. A majority of the samples analysed, however, contain moderate numbers of dinoflagellate cysts, but fewer miospores. The abundance of land derived detritus indicates the relatively close proximity of the shoreline. In the central and southern parts of the study area, sandstone and siltstone that are deposited in non-marine, fluvial, lacustrine or lagoonal environments show a general paucity of well-preserved palynofloras. Miospores of stratigraphic value are generally rare or absent although the majority of the samples are dominated by land derived detritus.PALYNOMORPH SUCCESSIONThe majority of the wells from northern Cyrenaica show a hiatus at the Jurassic Cretaceous boundary. Late Neocomian or Aptian sediments occur immediately above Middle or early Late Jurassic sediments. Well preserved Neocomian palynomorphs were recorded in wells A1-36, B1-36, Bla-18 and A1-45. The stratigraphical ranges of palynomorphs presented on the plate explanations are local ranges and are based on the studied intervals only. A preliminary palynological zonation of Late Jurassic (Late Kimmeridgian) to . . .

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Early Cretaceous

Danmarks Geologiske Undersøgelse Serie B ◽

10.34194/serieb.v8.7068 ◽

1982 ◽

Vol 8 ◽

pp. 45-49

Author(s):

Jens Morgen Hansen ◽

Arne Buch

Keyword(s):

North Sea ◽

Early Cretaceous ◽

Late Cretaceous ◽

Late Jurassic ◽

Significant Feature ◽

Marine Clay ◽

The North ◽

Marine Sand ◽

The North Sea ◽

Early Late

The Early Cretaceous sea primarily covered the same basinal regions as the Late Jurassic sea but, late in the Early Cretaceous the sea also covered Late Jurassic land masses. During Early Cretaceous time the topography of the North Sea region became gradually buried. The following major transgression comprises the transition Early/Late Cretaceous. At the Jurassic/ Cretaceous transition, the Late Cimmerian unconformity is a significant feature (fig. 24), known from large parts of the North Sea region. The subsequent transgression and sedimentation of marine clay (the Valhall Formation), and marine sand (the LC-1 Unit), started late in Late Jurassic. Therefore, the formations described in the present chapter also comprise sediments of Late Jurassic age. Thicknesses of the Lower Cretaceous sediments are given in fig. 15.

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Tromsø - Bjørnøya Composite Tectono-Sedimentary Element

Geological Society London Memoirs ◽

10.1144/m57-2018-19 ◽

2021 ◽

pp. M57-2018-19

Author(s):

Alf Eivind Ryseth ◽

Dominique Similox-Tohon ◽

Olaf Thieβen

Keyword(s):

Early Cretaceous ◽

Middle Jurassic ◽

Late Jurassic ◽

Barents Sea ◽

Structural Evolution ◽

Primary Source ◽

Source Rocks ◽

Late Paleozoic ◽

The North ◽

Sea Floor Spreading

AbstractThe Tromsø - Bjørnøya composite tectono-sedimentary element in the southwestern Barents Sea comprises strata of Late Paleozoic - Paleocene age. Since the Paleozoic Caledonian orogeny, the structural evolution of the CTSE is mainly related to extension, culminating in Late Jurassic - Early Cretaceous hyperextension. Some compressive deformation observed during Late Cretaceous - Paleogene times may relate to activity in the North Atlantic prior to the Early Eocene onset of sea floor spreading between Norway and Greenland.The sedimentary succession may be up to 14 km thick. It comprises Late Paleozoic continental facies, followed by carbonates, evaporites and eventually cherts and marine clastic material. The overlying Triassic - Paleocene succession is entirely siliciclastic, reflecting Triassic - Middle Jurassic deltaic and shallow marine conditions followed by deeper marine conditions during Late Jurassic - Paleocene times.Primary reservoirs are encountered in the latest Triassic - Middle Jurassic succession, with secondary reservoirs found in Late Jurassic - Early Cretaceous syn-rift succession, and in Paleocene strata. The primary source rock for petroleum is of Late Jurassic - Early Cretaceous age. Other source rocks include strata of Triassic and Barremian age, and a recently observed unit of Cenomanian - Early Turonian age.

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Late Jurassic-Early Cretaceous sandstones of Algan formation: composition, genesis, sources (North-West of Koryak Highland)

Moscow University Bulletin. Series 4. Geology ◽

10.33623/0579-9406-2020-6-48-58 ◽

2020 ◽

pp. 48-58

Author(s):

M. U. Gushchina ◽

A. V. Moiseev ◽

M. I. Tuchkova

Keyword(s):

Early Cretaceous ◽

High Speed ◽

Late Jurassic ◽

Small Distance ◽

Marine Environments ◽

North West ◽

The North ◽

Medium Speed ◽

Mineralogical Compositions

The article presents the results of studying the petrographic and mineralogical compositions of the sandstones of the Algan formation. Sandstones represented by pelitic-fine-medium-grained quartz-feldspar lithic arenites. Two tectonically combined sandstones lithotypes found. Lithotypes were formed in two heterochronous basins by high-speed and medium-speed turbidity flows, in moderately deep marine environments, in a relatively small distance from the coast. Sedimentation was near the deltas and prodeltas. The sources of these basins were different, related to the heterochronous volcanic areas in the north of the researched region.

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