A Permian Hydrozoan Mound, Yukon Territory

1971 ◽  
Vol 8 (8) ◽  
pp. 973-988 ◽  
Author(s):  
G. R. Davies
Keyword(s):  
Growth Form ◽  
Yukon Territory ◽  
Source Rocks ◽  
Lower Permian ◽  
Canal System ◽  
Rock Types ◽  
System A ◽  
Upper Paleozoic ◽  
Paleozoic Rocks ◽  
Richardson Mountains

A carbonate mound built by the hydrozoan Palaeoaplysina has been found in a poorly-exposed sequence of Lower Permian rocks in the northern Richardson Mountains of the Yukon Territory. Similar hydrozoan mounds have been described from Russia and northwestern United States. The Yukon mound is 12 ft (3.7 m) thick and at least 70 ft (21 m) long. It is underlain by marine siltstones and sandstones, and probably shale. The main mound rock is composed of curved hydrozoan plates enclosed in a bioclastic wackestone matrix, and is overlain successively by tubular–foram packstone and oolitic grainstone. Palaeoaplysina is characterized by a plate-like, laterally-expanding growth form, an internal canal system, a cellular calcareous skeleton, and 'mamelons' on the upper surface of well-preserved plates; 'mamelons' are the principal criterion for placing Palaeoaplysina in the Class Hydrozoa of the coelenterates.The Yukon mound is part of a thick sequence of Lower Permian terrigenous clastic and carbonate rocks deposited on the northern shelf of the ancestral Aklavik Arch. The repetition of similar rock types in the sequence indicates cyclicity, a thesis supported by similarities between the Yukon mound sequence and the Virgilian mound cycles in New Mexico.Lower Permian hydrozoan mounds and associated facies in the Pre-urals of Russia are known oil producers. The possibility exists that hydrozoan mounds, perhaps in multiple cyclic build-ups, may occur in upper Paleozoic rocks in the subsurface of the Yukon Territory. With suitable porosity development and source rocks, these predicted subsurface mounds could become hydrocarbon reservoirs and thus targets for oil exploration.

scholarly journals Genetic Types and Source of the Upper Paleozoic Tight Gas in the Hangjinqi Area, Northern Ordos Basin, China

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-14
Author(s):  
Xiaoqi Wu ◽  
Chunhua Ni ◽  
Quanyou Liu ◽  
Guangxiang Liu ◽  
Jianhui Zhu ◽  
...  
Keyword(s):  
Ordos Basin ◽  
Source Rocks ◽  
Lower Permian ◽  
Tight Gas ◽  
Upper Paleozoic ◽  
A Minor ◽  
Gas Component ◽  
Oil Type ◽  
Coal Type

The molecular and stable isotopic compositions of the Upper Paleozoic tight gas in the Hangjinqi area in northern Ordos Basin were investigated to study the geochemical characteristics. The tight gas is mainly wet with the dryness coefficient (C1/C1–5) of 0.853–0.951, andδ13C1andδ2H-C1values are ranging from-36.2‰to-32.0‰and from-199‰to-174‰, respectively, with generally positive carbon and hydrogen isotopic series. Identification of gas origin indicates that tight gas is mainly coal-type gas, and it has been affected by mixing of oil-type gas in the wells from the Shilijiahan and Gongkahan zones adjacent to the Wulanjilinmiao and Borjianghaizi faults. Gas-source correlation indicates that coal-type gas in the Shiguhao zone displays distal-source accumulation. It was mainly derived from the coal-measure source rocks in the Upper Carboniferous Taiyuan Formation (C3t) and Lower Permian Shanxi Formation (P1s), probably with a minor contribution from P1s coal measures from in situ Shiguhao zone. Natural gas in the Shilijiahan and Gongkahan zones mainly displays near-source accumulation. The coal-type gas component was derived from in situ C3t-P1s source rocks, whereas the oil-type gas component might be derived from the carbonate rocks in the Lower Ordovician Majiagou Formation (O1m).

Stratigraphy and structure of the Drake Point Anticline, Sabine Peninsula, Canadian Arctic Islands

2016 ◽  
Vol 53 (12) ◽  
pp. 1484-1500 ◽  
Author(s):  
Keith Dewing ◽  
Virginia Brake ◽  
Mathieu J. Duchesne ◽  
Thomas A. Brent ◽  
Nancy Joyce
Keyword(s):  
Early Cretaceous ◽  
Canadian Arctic ◽  
Source Rocks ◽  
Lower Permian ◽  
Hydrocarbon Generation ◽  
Lower Paleozoic ◽  
Upper Paleozoic ◽  
Differential Movement ◽  
Half Graben ◽  
Structural Relief

Modern processing methods were applied to 3400 line-kilometres of legacy seismic data from Sabine Peninsula of Melville Island in the Canadian Arctic Islands. Post-stack reprocessing improved the imaging, allowing new insight into the following issues: the northern extent of lower Paleozoic source rocks, extensional structures and rock types in the upper Paleozoic succession, the timing of the gentle Drake Point Anticline; and the age and extent of igneous sills. The central part of Sabine Peninsula is underlain by a half-graben containing upper Paleozoic strata. The half-graben fill is intersected by just one well, but it likely contains Upper Carboniferous to Lower Permian strata. The two largest conventional gas fields in Canada (Drake Point and Hecla) are hosted in Mesozoic strata within a gentle anticline that partially overlies the half-graben. Previously, the Drake Point Anticline was interpreted to have been formed during Eocene time. We propose that 280 m of the 430 m of structural relief on the Drake Anticline formed in response to uplift at the axis of the anticline in the Early Cretaceous, as shown by thinning of the Lower Cretaceous Christopher Formation over the Drake Anticline. The remaining 150 m of structural relief formed by differential movement between the Marryatt Point Syncline and Drake Point Anticline after the Early Cretaceous. Early Cretaceous relief on the Drake Point Anticline means it was at least partially present at the time of maximum hydrocarbon generation in the Late Cretaceous.

On the role of the Hercynian and Alpine thrusts in the Upper Paleozoic rocks of the Central and Eastern Pyrenees

1989 ◽  
Vol 3 (2) ◽  
pp. 135-147 ◽  
Author(s):  
Josep M. Casas ◽  
Francese Domingo ◽  
Josep Poblet ◽  
Albert Soler
Keyword(s):  
Eastern Pyrenees ◽  
Upper Paleozoic ◽  
Paleozoic Rocks

scholarly journals Light hydrocarbon geochemical characteristics and their application in Upper Paleozoic, Shenmu gas field, Ordos Basin

2016 ◽  
Vol 35 (1) ◽  
pp. 103-121 ◽  
Author(s):  
Wenxue Han ◽  
Shizhen Tao ◽  
Guoyi Hu ◽  
Weijiao Ma ◽  
Dan Liu ◽  
...  
Keyword(s):  
Natural Gas ◽  
Ordos Basin ◽  
Light Hydrocarbon ◽  
Source Rocks ◽  
Higher Plant ◽  
Gas Field ◽  
Gas Source ◽  
Upper Paleozoic ◽  
Methyl Cyclohexane ◽  
Normal Stage

Light hydrocarbon has abundant geochemical information, but there are few studies on it in Shenmu gas field. Taking Upper Paleozoic in Shenmu gas field as an example, authors use gas chromatography technology to study light hydrocarbon systematically. The results show that (1) The Shenmu gas field is mainly coal-derived gas, which is mixed by partial oil-derived gas due to the experiment data. (2) Based on K1, K2 parameter and Halpern star chart, the Upper Paleozoic gas in Shenmu gas field belongs to the same petroleum system and the depositional environment of natural gas source rocks should be homologous. (3) The source rocks are mainly from terrestrial higher plant origins and belong to swamp facies humic due to methyl cyclohexane index and Mango parameter intersection chart, which excluded the possibility of the Upper Paleozoic limestone as source rocks. (4) The isoheptane ranges from 1.45 to 2.69 with an average of 2.32, and n-heptane ranges from 9.48 to 17.68% with an average of 11.71%, which is below 20%. The maturity of Upper Paleozoic gas in Shenmu gas field is low-normal stage, which is consistent with Ro data. (5) The Upper Paleozoic natural gas in the Shenmu gas field did not experience prolonged migration or secondary changes, thus can be analyzed by light hydrocarbon index precisely.

scholarly journals A missing link in the peri-Gondwanan terrane collage: the Precambrian basement of the Moroccan Meseta and its lower Paleozoic cover

2018 ◽  
Vol 55 (1) ◽  
pp. 33-51 ◽  
Author(s):  
Dominik Letsch ◽  
Mohamed El Houicha ◽  
Albrecht von Quadt ◽  
Wilfried Winkler
Keyword(s):  
Carbonate Platform ◽  
Source Area ◽  
Source Rocks ◽  
Lower Paleozoic ◽  
Northern Margin ◽  
Precambrian Geology ◽  
The North ◽  
Late Cambrian ◽  
Paleozoic Rocks ◽  
Rifted Margin

This article provides stratigraphic and geochronological data from a central part of Gondwana’s northern margin — the Moroccan Meseta Domain. This region, located to the north of the Anti-Atlas area with extensive outcrops of Precambrian and lower Paleozoic rocks, has hitherto not received much attention with regard to its Precambrian geology. Detrital and volcanic zircon ages have been used to constrain sedimentary depositional ages and crustal affinities of sedimentary source rocks in stratigraphic key sections. Based on this, a four-step paleotectonic evolution of the Meseta Domain from the Ediacaran until the Early Ordovician is proposed. This evolution documents the transition from a terrestrial volcanic setting during the Ediacaran to a short-lived carbonate platform setting during the early Cambrian. The latter then evolved into a rifted margin with deposition of thick siliciclastic successions in graben structures during the middle to late Cambrian. The detritus in these basins was of local origin, and a contribution from a broader source area (encompassing parts of the West African Craton) can only be demonstrated for postrifting, i.e., laterally extensive sandstone bodies that seal the former graben. In a broader paleotectonic context, it is suggested that this Cambrian rifting is linked to the opening of the Rheic Ocean, and that several peri-Gondwanan terranes (Meguma and Cadomia–Iberia) may have been close to the Meseta Domain before drifting, albeit some of them seem to have been constituted by a distinctly different basement.

scholarly journals The Permo-Carboniferous genus Sagenodus and the beginning of modern lungfish

1997 ◽  
Vol 67 (1) ◽  
pp. 9-70 ◽  
Author(s):  
H.-P. Schultze ◽  
J. Chorn
Keyword(s):  
North America ◽  
The Body ◽  
Lower Permian ◽  
Red Beds ◽  
Faunal Assemblage ◽  
Canal System ◽  
Sensory Canal ◽  
Shallow Marine ◽  
Six Elements ◽  
Median Fins

The lungfish Sagenodus is a widespread Permo-Carboniferous genus found in Europe and North America. Important localities in the U.S.A. include Middle Pennsylvanian coals near Linton, Ohio, Upper Pennsylvanian deposits near Robinson and Hamilton, Kansas, and Peoria, Illinois; Lower Permian sediments near Cameron, Ohio; and Lower Permian “Red Beds” of Texas and Oklahoma. At least three species of Sagenodus were present in North America S. copeanus, S. periprion, S. serratus). S. ohiensis is represented solely by one skull. Knowledge of the osteology of Sagenodus is enhanced by the study of well-preserved but disassociated elements from Robinson, Kansas (S. copeanus) and Little Bitter Creek, Texas (S. serratus). The orbital series is now known to be comprised of six elements and the sensory canal system is more complex than previously realized. The only known articulated skeleton of this genus, from Hamilton Quarry, Kansas, permits a restoration of the entire animal including the median fins. The dorsal and anal fins are not separate; there is instead, a continuous fin around the caudal end of the body, as found in other post-Devonian lungfishes. Sagenodus is structurally intermediate between more primitive Devonian dipnoans and post-Paleozoic lungfishes. Evident trends can be seen in the reduction of bone (both number of bones and degree of ossification), the loss of cosmine, the nature of the scales, the structure and histology of tooth plates, and the configuration of the median fins. Sagenodus is a member of a euryhaline faunal assemblage that can be found from shallow marine to freshwater deposits.

The Blind Creek Limestone, Keremeos, British Columbia: Structure and Regional Tectonic Significance

1975 ◽  
Vol 12 (11) ◽  
pp. 1929-1933
Author(s):  
W. C. Barnes ◽  
J. V. Ross
Keyword(s):  
British Columbia ◽  
Compressive Stress ◽  
Ductile Deformation ◽  
Large Block ◽  
Stress Direction ◽  
Upper Paleozoic ◽  
Tectonic Significance ◽  
Regional Tectonic ◽  
Similar Body ◽  
Paleozoic Rocks

A large block of Upper Paleozoic limestone at Blind Creek near Keremeos, B.C. was emplaced by dry gravity sliding, probably associated with uplift related to nearby Eocene volcanism. The block is a nearly flat tabular unit, exposed over an area of 650 m by 1300 m, and is separated from underlying chaotic breccias derived from adjacent Paleozoic rocks and from Eocene volcanic flow rocks by a sole fault. The block comprises two lithologically and tectonically distinct units, a lower imbricated unit consisting of several slices repeating the same sequence of strata, separated from an upper unit of massive limestone by a low-angle fault. Within the imbricated unit, early faults emanate from lenticular masses of breccia along the sole, become increasingly steeper upward, and are truncated above by the upper low angle fault. Associated minor folds and fractures have a clockwise sense of rotation. Later fractures and associated minor folds have the opposite dip and sense of rotation. These two subsets comprise a conjugate set whose inferred compressive stress direction coincides with the present overall dip direction of the entire mass.The northwesterly adjacent autochthonous Olalla limestone, or a similar body now buried by younger units, is a likely source for the Blind Creek allochthon.Absence of any structures within the limestone indicative of ductile deformation contrasts markedly with those of the highly deformed rocks of the Old Tom and Shoemaker Formations, the Kobau Group, and the nearby gneisses of the western Shuswap Complex.

SIMPSON DESERT SUB-BASIN—A PROMISING PERMIAN TARGET

1973 ◽  
Vol 13 (1) ◽  
pp. 33
Author(s):  
George E. Williams
Keyword(s):  
Lower Jurassic ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Seismic Exploration ◽  
Upper Permian ◽  
Lower Permian ◽  
Geophysical Surveys ◽  
Carbonaceous Shales ◽  
Cap Rock ◽  
Simpson Desert

Sediments of three major basins occur in the Simpson Desert region of central Australia:Cambro -Ordovician dolomites and sandstones, and Siluro- Devonian conglomerates, sandstones and shales, related to the Amadeus Basin:Permian conglomerates, sandstones, shales and coals of the Simpson Desert Sub-basin, the extensive eastern lobe of the Pedirka Basin:Mesozoic sandstones and shales of the Eromanga Basin.Principal petroleum exploration interest is presently directed toward the Permian sediments, which have many features in common with the petroleum producing Permian section of the neighbouring Cooper Basin.Lower Permian sediments known from drilling in the Simpson Desert Sub-basin comprise glaciofluvial conglomerates and sandstones overlain by fluvial and lacustrine sandstones, silt-stones, shales and coals. The maximum thickness encountered in wells is 1,479 ft (448 m) in Mokari 1.Recent seismic exploration 50 to 100 mi (80-160 km) west of Poeppel Corner in the deeper part of the Simpson Desert Sub-basin indicates that an additional sediment package up to 1,500 ft (350 m) thick occurs at depths of 6,500 to 7,500 ft (2,000-2,300 m) between Lower Permian and Lower Jurassic sections. This sediment package, nowhere penetrated by drilling, may be Middle to Upper Permian and/or Triassic in age. It is of great significance to petroleum exploration in the sub-basin and substantially upgrades the hydrocarbon prospects of the region.Permian sediments in the Simpson Desert Sub-basin thin by onlap, wedge out and stripping over the crests of anticlinal growth structures. Crestal sediments probably comprise mainly porous sandstones, grading off-structure into thicker sequences containing carbonaceous shales and coals. Such carbonaceous potential source rocks are probably best developed in the deepest part of the sub-basin, where Triassic cap rock may also be present. Two particularly promising drilling targets—the Colson Anticline and the East Colson Anticline—have been revealed by recent geophysical surveys in this portion of the sub-basin. Wells drilled on these structures may intersect Permo-Triassic sediments up to 2,200 + ft (670 in) thick which are comparable in age and type with producing sections in the Cooper Basin.

PETROLEUM SYSTEMS IN TASMANIA'S FRONTIER ONSHORE BASINS

2000 ◽  
Vol 40 (1) ◽  
pp. 26
Author(s):  
M.R. Bendall C.F. Burrett ◽  
H.J. Askin
Keyword(s):  
Oil And Gas ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Late Triassic ◽  
Upper Permian ◽  
Lower Permian ◽  
Peak Oil ◽  
Petroleum Systems ◽  
Upper Proterozoic ◽  
Oil Seep

Sedimentary successions belonging to three petroleum su persy stems can be recognised in and below the Late Carboniferous to Late Triassic onshore Tasmania Basin. These are the Centralian, Larapintine and Gondwanan. The oldest (Centralian) is poorly known and contains possible mature source rocks in Upper Proterozoic dolomites. The Larapintine 2 system is represented by rocks of the Devonian fold and thrust belt beneath the Tasmania Basin. Potential source rocks are micrites and shales within the 1.8 km-thick tropical Ordovician Gordon Group carbonates. Conodont CAI plots show that the Gordon Group lies in the oil and gas windows over most of central Tasmania and probably under much of the Tasmania Basin. Potential reservoirs are the upper reefal parts of the Gordon Group, paleokarsted surfaces within the Gordon Group and the overlying sandstones of the Siluro-Devonian Tiger Range and Eldon Groups. Seal rocks include shales within the Siluro-Devonian and Upper Carboniferous-Permian tillites and shales.The Gondwanan supersystem is the most promising supersystem for petroleum exploration within the onshore Tasmania Basin. It is divided into two petroleum systems— the Early Permian Gondwanan 1 system, and the Late Permian to Triassic Gondwanan 2 system. Excellent source rocks occur in the marine Tasmanite Oil Shale and other sections within the Lower Permian Woody Island and Quamby Formations of the Gondwanan 1 system and within coals and freshwater oil shales of the Gondwanan 2 system. These sources are within the oil and gas windows across most of the basin and probably reached peak oil generation at about 100 Ma. An oil seep, sourced from a Tasmanites-rich, anoxic shale, is found within Jurassic dolerite 40 km WSW of Hobart. Potential Gondwanan 1 reservoirs are the glaciofluvial Faulkner Group sandstones and sandstones and limestones within the overlying parts of the glaciomarine Permian sequence. The Upper Permian Ferntree Mudstone Formation provides an effective regional seal. Potential Gondwanan 2 reservoirs are the sandstones of the Upper Permian to Norian Upper Parmeener Supergroup. Traps consisting of domes, anticlines and faults were formed probably during the Early Cretaceous. Preliminary interpretation of a short AGSO seismic profile in the Tasmania Basin shows that, contrary to earlier belief, structures can be mapped beneath extensive and thick (300 m) sills of Jurassic dolerite. In addition, the total section of Gondwana to Upper Proterozoic to Triassic sediments appears to be in excess of 8,500 m. These recent studies, analysis of the oil seep and drilling results show that the Tasmanian source rocks have generated both oil and gas. The Tasmania Basin is considered prospective for both petroleum and helium and is comparable in size and stratigraphy to other glaciomarine-terrestrial Gondwanan basins such as the South Oman and Cooper Basins.

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