The Yenisei-Khatanga Composite Tectono-Sedimentary Element, Northern Siberia

2021 ◽  
pp. M57-2021-15
Author(s):  
E. V. Deev ◽  
G. G. Shemin ◽  
V. A. Vernikovsky ◽  
O. I. Bostrikov ◽  
P. A. Glazyrin ◽  
...  

AbstractThe Yenisei-Khatanga Composite Tectono-Sedimentary Element (YKh CTSE) is located between the Siberian Craton and the Taimyr-Severnaya Zemlya fold-and-thrust belt. The total thickness of the Mesoproterozoic-Cenozoic sediments of YKh CTSE reaches 20 to 25 km. They are divided into four tectono-sedimentary elements (TSE): (i) Mesoproterozoic-early Carboniferous Siberian Craton continental margin, (ii) middle Carboniferous-Middle Triassic syn-orogenic Taimyr foreland basin, (iii) late Permian-Early Triassic syn-rift, and (iv) Triassic-Early Paleocene post-rift. The last one is the most important in terms of its petroleum potential and is the most drilled part of the CTSE. Its thickness accounts for half of the total thickness of YKh CTSE. The margins of the post-rift TSE and the inner system of inversion swells and adjacent troughs and depressions were shaped by three tectonic events: (i) middle Carboniferous-Middle Triassic Taimyr orogeny, (ii) Late Jurassic-Early Cretaceous Verkhoyansk orogeny, (iii) Late Cenozoic uplift. These processes led to more intense migration of hydrocarbons, the trap formation and their infill with hydrocarbons. Triassic, Jurassic, and Lower Cretaceous source rocks are mostly gas-prone, and among 20 discovered fields in Jurassic and Cretaceous plays, 17 are gas or mixed-type fields.

2021 ◽  
pp. M57-2021-29
Author(s):  
A.K. Khudoley ◽  
S.V. Frolov ◽  
G.G. Akhmanov ◽  
E.A. Bakay ◽  
S.S. Drachev ◽  
...  

AbstractAnabar-Lena Composite Tectono-Sedimentary Element (AL CTSE) is located in the northern East Siberia extending for c. 700 km along the Laptev Sea coast between the Khatanga Bay and Lena River delta. AL CTSE consists of rocks from Mesoproterozoic to Late Cretaceous in age with total thickness reaching 14 km. It evolved through the following tectonic settings: (1) Meso-Early Neoproterozoic intracratonic basin, (2) Ediacaran - Early Devonian passive margin, (3) Middle Devonian - Early Carboniferous rift, (4) late Early Carboniferous - latest Jurassic passive margin, (5) Permian foreland basin, (6) Triassic to Jurassic continental platform basin and (7) latest Jurassic - earliest Late Cretaceous foreland basin. Proterozoic and lower-middle Paleozoic successions are composed mainly by carbonate rocks while siliciclastic rocks dominate upper Paleozoic and Mesozoic sections. Several petroleum systems are assumed in the AL CTSE. Permian source rocks and Triassic sandstone reservoirs are the most important play elements. Presence of several mature source rock units and abundant oil- and gas-shows (both in wells and in outcrops), including a giant Olenek Bitumen Field, suggest that further exploration in this area may result in economic discoveries.


2018 ◽  
Vol 69 (4) ◽  
pp. 410-436 ◽  
Author(s):  
Magdalena Pupp ◽  
Achim Bechtel ◽  
Reinhard Gratzer ◽  
Maria Heinrich ◽  
Sharadiya Kozak ◽  
...  

Abstract Oligocene successions in the North Alpine Foreland Basin (NAFB) and the Western Carpathians reflect Paratethys-wide paleogeographic changes, which also control their petroleum potential. Whereas these rocks have been studied in detail in both areas, the transition zone is still under-researched. In order to fill this gap, the Oligocene succession in the Waschberg Zone, comprising the Ottenthal Formation (NP21–23) and the overlying Thomasl Formation (NP23–24) has been studied using outcrop (Waldweg section) and borehole samples (Thomasl, Poysdorf) and a multidisciplinary approach. The Ottenthal Formation is subdivided from base to top into marls and shales (Ottenthal Mbr.), diatomaceous shales (Galgenberg Mbr.) and marlstones (Dynow Mbr.). Biogenic silica contents, determined using atomic absorption spectroscopy, reach 30 wt. % in the carbonate-free Galgenberg Member, but also in the Dynow Members, which is characterized by upward decreasing productivity of calcareous nannoplankton. Close lithological relations exist with the Oligocene succession in the NAFB, but diatoms are largely missing in the latter. Organic matter contents are surprisingly low in the Ottenthal and Thomasl formations in the Waldweg section, which therefore are poor hydrocarbon source rocks. In contrast, the Thomasl Formation, encountered in the Thomasl and Poysdorf boreholes, holds a fair to good hydrocarbon potential (~ 2.2–2.5 wt. % TOC; type III and type II kerogen) and may generate 1.0 to 1.6 tons of hydrocarbons/m2. Obviously TOC contents of borehole samples are significantly higher than in outcrop samples. Because of severe indications of weathering (e.g., presence of gypsum and jarosite), a detrimental effect of weathering on the samples from the Waldweg section cannot be excluded. Biomarker data suggest a nearshore depositional environment with changing oxygen-availability and salinity. Vitrinite reflectance measurements show that the investigated sections are thermally immature.


2021 ◽  
pp. M57-2020-20
Author(s):  
E. Henriksen ◽  
D. Ktenas ◽  
J. K. Nielsen

AbstractThe Finnmark Platform Composite Tectono-Sedimentary Element (CTSE), located in the southern Barents Sea, is a northward-dipping monoclinal structural unit. It covers most of the southern Norwegian Barents Sea where it borders the Norwegian Mainland. Except for the different age of basement, the CTSE extends eastwards into the Kola Monocline on the Russian part of the Barents Sea.The general water depth varies between 200-350 m, and the sea bottom is influenced by Plio-Pleistocene glaciations. A high frequency of scour marks and deposition of moraine materials exists on the platform areas. Successively older strata sub-crop below the Upper Regional Unconformity (URU, which was) formed by several glacial periods.Basement rocks of Neoproterozoic age are heavily affected by the Caledonian Orogeny, and previously by the Timanide tectonic compression in the easternmost part of the Finnmark Platform CTSE.Depth to crystalline basement varies considerably and is estimated to be from 4-5 to 10 km. Following the Caledonian orogenesis, the Finnmark Platform was affected by Lower to Middle Carboniferous rifting, sediment input from the Uralian Orogen in the east, the Upper Jurassic / Lower Cretaceous rift phase and the Late Plio-Pleistocene isostatic uplift.A total of 8 exploration wells drilled different targets on the platform. Two minor discoveries have been made proving presence of both oil and gas and potential sandstone reservoirs of good quality identified in the Visean, Induan, Anisian and Carnian intervals. In addition, thick sequences of Perm-Carboniferous carbonates and spiculitic chert are proven in the eastern Platform area. The deep reservoirs are believed to be charged from Paleozoic sources. A western extension of the Domanik source rocks well documented in the Timan-Pechora Basin may exist towards the eastern part of the Finnmark Platform. In the westernmost part, charge from juxtaposed down-faulted basins may be possible.


2019 ◽  
Vol 27 (1) ◽  
pp. 57-78
Author(s):  
D. V. Alexeiev ◽  
Yu. S. Biske ◽  
A. V. Djenchuraeva ◽  
B. Wang ◽  
O. L. Kossovaya ◽  
...  

The field revision of the Carboniferous and Lower Permian stratigraphy of the northern Bogdashan (South Junggar, Northwest China) shows that the Lower to Middle Carboniferous island arc volcanic rocks, widely developed in this region, are overlapped everywhere by carbonate and terrigenous-carbonate sediments, containing occasional lava flows and overlain up the section by thick terrigenous series practically devoid of volcanic rocks. The deposition of limestone occurred at the stage of dying off of a volcanic arc, and the question of their age is of fundamental importance for dating this event. Carbonates are represented by facies of lagoons, shoals, and bioherms that formed on the leveled surface of the arc and on the slopes of the last active volcanoes. Bioherms are Waulsortian mounds and are mainly composed of algal limestones and carbonate mud. There are no framestones composed of corals and sponges (chaetetids) typical of the tropical zone. The facies of shallow crinoid-fusulinid limestones typical of the adjacent territories of the Southern Tien Shan and Tarim are poorly represented. Paleogeographically, the position of bioherms corresponds to the northern boundary of the realm of Pennsylvanian reefs. On the basis of foraminifers, brachiopods, and corals, the age of carbonates is early Moscovian (ca. 315–310 Ma). Cessation of island-arc volcanism, followed by the accumulation of limestone in Bogdashan, occurred sub-synchronously with formation of the West Junggar (Bayingou) suture and may reflect docking of the Bogdashan arc to the Yili active margin of the Kazakhstan continent. Further subsidence of Bogdashan and adjacent regions of the Junggar and Turfan basins, which was somewhat slower at the end of the Carboniferous and more intense in the Early and Middle Permian, may reflect the development of the foreland basin that formed along the northern flank of the Tien Shan orogen. Marine facies were locally preserved in this basin until the Artinskian (ca. 285 Ma), and later the Junggar and Turfan basins lost connection to the ocean and developed in continental environments.


1993 ◽  
Vol 57 (388) ◽  
pp. 423-436 ◽  
Author(s):  
P. K. Seccombe ◽  
J. Ju ◽  
A. S. Andrew ◽  
B. L. Gulson ◽  
K. J. Mizon

AbstractThe Hill goldfield, NSW, Australia, is an example of a syntectonic, slate-belt gold deposit formed in a multiply deformed, Late Silurian slate-metagreywacke turbidite sequence. Gold is confined to bedding-parallel veins and discordant leader veins composed of as many as four generations of quartz, accompanied by phyllosilicates, carbonates and minor sulphides. Vein formation and gold deposition was apparently synchronous with Early Carboniferous metamorphism and deformation. Homogenisation temperatures (Th) for fluid inclusions in vein quartz demonstrate five groupings in the temperature intervals 350-280°C 280-250°C 250-190°C 190-150°C and 150-110°C corresponding to a variety of primary and secondary inclusions developed during four periods of vein quartz deposition under a generally declining temperature regime. Inclusion fluids are characterised by a low salinity of around 0.1 to 3.6 wt. % NaCl equivalent. The dominant gas phase present in the inclusion fluids varies from N2 in the early stages of the paragenesis, through CH 4 during the main episode of gold deposition, to CO2- rich fluids associated with late-stage mineralisation. δ18O values for vein quartz (range 15.1-17.1‰) and vein carbonate (range 11.3-13.4‰) are typical of metamorphic mineralisation. δD composition of hydrous minerals and inclusion fluids (range −53 to −138‰) suggest an influx of meteoric water in the later mineralising fluids. This conclusion is supported by δ13C data for vein calcite (range −2.5 to −9.7%0). δ34S composition of vein pyrrhotite and pyrite ranges from 6.9 to 7.8‰ early in the paragenesis, to lighter values (around 4.2 to 5.8%0) accompanying late gold deposition from more oxidising fluids. Sulphur isotope data imply a sulphur source from underlying turbidites and an increase in fluid oxidation state during mineralisation . Lead isotope measurements on vein pyrite, arseno py rite, galena and gold are characterised by two isotope populations with 207Pb/206Pb ratios of 0.862 and 0.860, which define two discrete mineralising events during vein formation. Consistency between data from vein minerals and lead isotope signatures for potential source rocks indicate that lead was derived from the sedimentary pile.


First Break ◽  
2014 ◽  
Vol 32 (12) ◽  
Author(s):  
Henry David ◽  
Constantinos Tzimeas ◽  
Paschalia Kiomourtzi ◽  
Panagiotis Konstantopoulos ◽  
George Panagopoulos ◽  
...  

2001 ◽  
Vol 41 (1) ◽  
pp. 139 ◽  
Author(s):  
G.J. Ambrose ◽  
P.D. Kruse ◽  
P.E. Putnam

The Georgina Basin is an intracratonic basin on the central-northern Australian craton. Its southern portion includes a highly prospective Middle Cambrian petroleum system which remains largely unexplored. A plethora of stratigraphic names plagued previous exploration but the lithostratigraphy has now been rationalised using previously unpublished electric-log correlations and seismic and core data.Neoproterozoic and Lower Palaeozoic sedimentary rocks of the southern portion of the basin cover an area of 100,000 km2 and thicken into two main depocentres, the Toko and Dulcie Synclines. In and between these depocentres, a Middle Cambrian carbonate succession comprising Thorntonia Limestone and Arthur Creek Formation provides a prospective reservoir-source/seal couplet extending over 80,000 km2. The lower Arthur Creek Formation includes world class microbial source rocks recording total organic carbon (TOC) values of up to 16% and hydrocarbon yields up to 50 kg/tonne. This blanket source/seal unconformably overlies sheetlike, platform dolostone of the Thorntonia Limestone which provides the prime target reservoir. Intra- Arthur Creek high-permeability grainstone shoals are important secondary targets.In the Toko Syncline, Middle Cambrian source rocks entered the oil window during the Ordovician, corresponding to major sediment loading at this time. The gas window was reached prior to structuring associated with the Middle Devonian-Early Carboniferous Alice Springs Orogeny, and source rocks today lie in the dry gas window. In contrast, high-temperature basement granites have resulted in overmaturity of the Arthur Creek Formation in the Dulcie Syncline area. On platform areas adjacent to both these depocentres source rocks reached peak oil generation shortly after the Alice Springs Orogeny; numerous structural leads have been identified in these areas. In addition, an important stratigraphic play occurs in the Late Cambrian Arrinthrunga Formation (Hagen Member) on the southwestern margin of the basin. Key elements of the play are the pinchout of porous oil-stained, vuggy dolostone onto basement where top seal is provided by massive anhydrite while underlying Arthur Creek Formation shale provides a potential source.


2008 ◽  
Vol 48 (1) ◽  
pp. 53 ◽  
Author(s):  
Chris Uruski ◽  
Callum Kennedy ◽  
Rupert Sutherland ◽  
Vaughan Stagpoole ◽  
Stuart Henrys

The East Coast of North Island, New Zealand, is the site of subduction of the Pacific below the Australian plate, and, consequently, much of the basin is highly deformed. An exception is the Raukumara Sub-basin, which forms the northern end of the East Coast Basin and is relatively undeformed. It occupies a marine plain that extends to the north-northeast from the northern coast of the Raukumara Peninsula, reaching water depths of about 3,000 m, although much of the sub-basin lies within the 2,000 m isobath. The sub-basin is about 100 km across and has a roughly triangular plan, bounded by an east-west fault system in the south. It extends about 300 km to the northeast and is bounded to the east by the East Cape subduction ridge and to the west by the volcanic Kermadec Ridge. The northern seismic lines reveal a thickness of around 8 km increasing to 12–13 km in the south. Its stratigraphy consists of a fairly uniformly bedded basal section and an upper, more variable unit separated by a wedge of chaotically bedded material. In the absence of direct evidence from wells and samples, analogies are drawn with onshore geology, where older marine Cretaceous and Paleogene units are separated from a Neogene succession by an allochthonous series of thrust slices emplaced around the time of initiation of the modern plate boundary. The Raukumara Sub-basin is not easily classified. Its location is apparently that of a fore-arc basin along an ocean-to-ocean collision zone, although its sedimentary fill must have been derived chiefly from erosion of the New Zealand land mass. Its relative lack of deformation introduces questions about basin formation and petroleum potential. Although no commercial discoveries have been made in the East Coast Basin, known source rocks are of marine origin and are commonly oil prone, so there is good potential for oil as well as gas in the basin. New seismic data confirm the extent of the sub-basin and its considerable sedimentary thickness. The presence of potential trapping structures and direct hydrocarbon indicators suggest that the Raukumara Sub-basin may contain large volumes of oil and gas.


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