Allochthonous Permian micro- and macrofauna, Kamloops area, British Columbia

1985 ◽  
Vol 22 (3) ◽  
pp. 442-451 ◽  
Author(s):  
Samuel J. Nelson ◽  
Eric R. Nelson

The first waagenophyllid coral to be described from the Western Hemisphere has been found in Permian rocks of the "Harper Ranch Group," near Kamloops, southern British Columbia. It is Parawentzelella?(Miyagiella) johnstonae sp. nov., associated with the tabulate coral Multithecopora?larushi sp. nov., numerous brachiopods, and other fossils. The containing rocks are considered to be allochthonous, originating in the western part of the Paleopacific Tethyan Ocean or in an island-arc complex farther to the north.The outcrop yielding the fossils appears to be a stratigraphic misfit, both in age and origin. Fusulinids from adjacent areas are of Early Permian (Wolfcampian) age but those associated with the fossils indicate a Late Permian (Guadalupian) age. These conflicting dates cannot, at present, be reconciled. The Tethyan origin of the fauna also contrasts with that of surrounding rocks, which are "non-Tethyan."

1989 ◽  
Vol 63 (2) ◽  
pp. 158-181 ◽  
Author(s):  
Calvin H. Stevens ◽  
Barbara Rycerski

Twenty-two species of Early Permian colonial rugose corals belonging to 12 genera from 10 locations in the Stikine River area in northwestern British Columbia, Canada, are described. These include three new species ofFomichevella(F. magna, F. southeri, F. bamberi); two species ofHeintzella; five species ofHeritschioides, of which three are new (H. bagleyae, H. garvinae, H. hoganae); two new species ofParaheritschioides(P. jennyi, P. wickenae); one new species questionably assigned toKleopatrina(K.?stikinensis); two new species ofPetalaxis(P. guaspariniae, P. neriae); and two new species ofLytvophyllum(L.?mongeri, L. wersoni). In addition, five new species assigned to five new genera are here namedEastonastraea complexa, Fedorowskiella simplex, Pararachnastraea lewisi, Stikineastraea thomasi, andWilsonastraea rigbyi.These corals occur in rocks forming part of the Stikine terrane, the largest tectonostratigraphic unit in western Canada. This coral fauna shows a very close affinity with that of the Lower Permian McCloud Limestone of the eastern Klamath Mountains of northern California, and there is some similarity to the Coyote Butte fauna of central Oregon. Several species compare most closely with species from Spitsbergen, but there are few similarities with any cratonal North American faunas and none with Tethyan faunas.


2003 ◽  
Vol 43 (1) ◽  
pp. 495 ◽  
Author(s):  
P.A. Arditto

The study area is within PEP 11, which is more than 200 km in length, covers an area over 8,200 km2 and lies immediately offshore of Sydney, Australia’s largest gas and petroleum market on the east coast of New South Wales. Permit water depths range from 40 m to 200 m. While the onshore Sydney Basin has received episodic interest in petroleum exploration drilling, no deep exploration wells have been drilled offshore.A reappraisal of available data indicates the presence of suitable oil- and wet gas-prone source rocks of the Late Permian coal measure succession and gas-prone source rocks of the middle to early Permian marine outer shelf mudstone successions within PEP 11. Reservoir quality is an issue within the onshore Permian succession and, while adequate reservoir quality exists in the lower Triassic succession, this interval is inferred to be absent over much of PEP 11. Quartz-rich arenites of the Late Permian basal Sydney Subgroup are inferred to be present in the western part of PEP 11 and these may form suitable reservoirs. Seismic mapping indicates the presence of suitable structures for hydrocarbon accumulation within the Permian succession of PEP 11, but evidence points to significant structuring post-dating peak hydrocarbon generation. Uplift and erosion of the order of 4 km (based on onshore vitrinite reflectance studies and offshore seismic truncation geometries) is inferred to have taken place over the NE portion of the study area within PEP 11. Published burial history modelling indicates hydrocarbon generation from the Late Permian coal measures commenced by or before the mid-Triassic and terminated during a mid-Cretaceous compressional uplift prior to the opening of the Tasman Sea.Structural plays identified in the western and southwestern portion of PEP 11 are well positioned to contain Late Permian clean, quartz-rich, fluvial to nearshore marine reservoir facies of the coal measures. These were sourced from the western Tasman Fold Belt. The reservoir facies are also well positioned to receive hydrocarbons expelled from adjacent coal and carbonaceous mudstone source rock facies, but must rely on early trap integrity or re-migrated hydrocarbons and, being relatively shallow, have a risk of biodegradation. Structural closures along the main offshore uplift appear to have been stripped of the Late Permian coal measure succession and must rely on mid-Permian to Early Permian petroleum systems for hydrocarbon generation and accumulation.


2000 ◽  
Vol 74 (2) ◽  
pp. 363-366 ◽  
Author(s):  
Francisco Sour-Tovar ◽  
Sara A. Quiroz-Barroso ◽  
Shelton P. Applegate

A newly discovered Helicoprion specimen from the Patlanoaya Formation, State of Puebla, represents the southernmost finding of this genus of edestoid-shark in the Western Hemisphere. It was found in sediments assigned to the upper part of the Early Permian, based on its association with Perrinites hilli, an index ammonoid for the Leonardian age.


2016 ◽  
Author(s):  
Graciela Piñeiro ◽  
Pablo Núñez Demarco ◽  
Melitta D Meneghel

The hypotheses about the origin of the primitive amniotic tarsus are very speculative. Early studies argued that the origin of the astragalus, one of the largest proximal bones in the tarsus of basal amniotes, was produced by either the fusion of two, three, or even four of the original tarsal bones, the intermedium, the tibiale and the proximal centralia (c4 and c3), or that the intermedium alone transforms into the primitive astragalus. More recent studies have shown that the structure of the tarsus in Captorhinus supports the former hypothesis about a fusion of the intermedium, the tibiale, the proximal centrale (c4) and eventually c3, producing a purportedly multipartite structure of the amniotic astragalus, but the issue remained contentious. Very well preserved tarsi of the Early Permian aquatic amniote Mesosaurus tenuidens Gervais, 1864-1865, which represent the most complete ontogenetic succession known for a basal amniote (the other exceptional one is provided by the Late Permian diapsid Hovasaurus boulei Piveteau, 1926), suggest that there is more than one ossification center for the astragalus and that these fuse during late embryonic stages or maybe early after birth. A non-hatched Mesosaurus in an advanced stage of development shows that the tarsus is represented by a single bone, most probably the astragalus, which seems to be formed by the suturing of three bones, which we interpret as being the intermedium, the tibiale, which could have already integrated the c4 in an earlier stage of the development, and the c3. An amniote-like tarsal structure is observed in very basal Carboniferous and Permian tetrapods such as Proterogyrinus, Gephyrostegus, the diadectids Diadectes and Orobates, some microsaurs like Tuditanus and Pantylus, and possibly Westlothiana, taxa that were all considered as true amniotes in their original descriptions. Therefore, the structure of the amniotic tarsus, including the configuration of the proximal series formed by the astragalus and the calcaneum, typically a pair of enlarged bones, could have been established well before the first recognized amniote walked on Earth. Accordingly, the tarsus of these taxa does not constitute specialized convergences that appeared in unrelated groups, they might be instead, part of a transformation series that involves taxa closely related to the early amniotes as some hypotheses have suggested.


1996 ◽  
Vol 33 (8) ◽  
pp. 1105-1126 ◽  
Author(s):  
G. E. Ray ◽  
I. C. L. Webster ◽  
G. L. Dawson

The Nicola Group at Hedley, British Columbia, is a late Carnian to late Norian (Late Triassic) sequence of calcareous sedimentary and arc-related volcaniclastic rocks. It was deposited on a tectonically active paleoslope that marked either the rifted eastern margin of the shallow-marine Nicola basin or the faulted edge of an intrabasinal platform. The lower part of the Nicola Group comprises a succession of four essentially coeval sedimentary facies. From east to west across the district, these are informally named the thin (approx. 200 m), shallow-marine, limestone-dominant French Mine formation; the thicker, calcareous siltstone-dominant Hedley and Chuchuwayha formations in the central part of the district; and the thick (up to 2200 m), deeper water and argillite-dominant Stemwinder formation. These facies are all blanketed by the Whistle formation, a 1200 m thick unit of basaltic tuff and tuffaceous sediment whose base is marked by a gravity-slide megabreccia, the Copperfield breccia. The Nicola arc at Hedley was associated with two plutonic episodes. Oldest are the Hedley intrusions, which are related to economic Au skarns, including the Nickel Plate deposit, which has produced over 71 t of gold from 13.4 Mt of ore. The Hedley intrusions are similar in composition (quartz gabbro to quartz diorite) and overall metaluminous chemistry to other island-arc-generated plutons related to many Cu and Fe skarns in British Columbia, although they are less evolved. They also differ in having lower Fe2O3/FeO ratios (avg. 0.23), indicating a reduced oxidation state, and higher Ba/La and Sc/Nb ratios. A slightly younger plutonic episode produced the 193 Ma (Early Jurassic) Bromley batholith and the 194 Ma Mount Riordan stock; the latter is associated with the Mount Riordan (Crystal Peak) industrial garnet skarn. Gold skarns are preferentially developed in areas where the Hedley intrusions cut the Hedley and French Mine formations. The Au skarn ore is marked by anomalous As, Bi, Te, and Co values, and by high pyrrhotite/pyrite and pyroxene/garnet ratios. It is distinct from the ore of Fe, Cu, Mo, Pb–Zn, W, and Sn skarns by its very low Cu/Au, Zn/Au, and Ag/Au ratios (avg. 97, 18, and 12, respectively).


2016 ◽  
Author(s):  
Graciela Piñeiro ◽  
Pablo Núñez Demarco ◽  
Melitta D Meneghel

The hypotheses about the origin of the primitive amniotic tarsus are very speculative. Early studies argued that the origin of the astragalus, one of the largest proximal bones in the tarsus of basal amniotes, was produced by either the fusion of two, three, or even four of the original tarsal bones, the intermedium, the tibiale and the proximal centralia (c4 and c3), or that the intermedium alone transforms into the primitive astragalus. More recent studies have shown that the structure of the tarsus in Captorhinus supports the former hypothesis about a fusion of the intermedium, the tibiale, the proximal centrale (c4) and eventually c3, producing a purportedly multipartite structure of the amniotic astragalus, but the issue remained contentious. Very well preserved tarsi of the Early Permian aquatic amniote Mesosaurus tenuidens Gervais, 1864-1865, which represent the most complete ontogenetic succession known for a basal amniote (the other exceptional one is provided by the Late Permian diapsid Hovasaurus boulei Piveteau, 1926), suggest that there is more than one ossification center for the astragalus and that these fuse during late embryonic stages or maybe early after birth. A non-hatched Mesosaurus in an advanced stage of development shows that the tarsus is represented by a single bone, most probably the astragalus, which seems to be formed by the suturing of three bones, which we interpret as being the intermedium, the tibiale, which could have already integrated the c4 in an earlier stage of the development, and the c3. An amniote-like tarsal structure is observed in very basal Carboniferous and Permian tetrapods such as Proterogyrinus, Gephyrostegus, the diadectids Diadectes and Orobates, some microsaurs like Tuditanus and Pantylus, and possibly Westlothiana, taxa that were all considered as true amniotes in their original descriptions. Therefore, the structure of the amniotic tarsus, including the configuration of the proximal series formed by the astragalus and the calcaneum, typically a pair of enlarged bones, could have been established well before the first recognized amniote walked on Earth. Accordingly, the tarsus of these taxa does not constitute specialized convergences that appeared in unrelated groups, they might be instead, part of a transformation series that involves taxa closely related to the early amniotes as some hypotheses have suggested.


1989 ◽  
Vol 29 (1) ◽  
pp. 450 ◽  
Author(s):  
John F. Marshall ◽  
Chao- Shing Lee ◽  
Douglas C. Ramsay ◽  
Aidan M.G. Moore

The major tectonic and stratigraphic elements of the offshore North Perth Basin have been delineated from regional BMR multichannel seismic reflection lines, together with industry seismic and well data. This analysis reveals that three sub- basins, the Edel, Abrolhos and Houtman Sub- basins, have formed as a result of three distinct episodes of rifting within the offshore North Perth Basin during the Early Permian, Late Permian and Late Jurassic respectively. During this period, rifting has propagated from east to west, and has culminated in the separation of this part of the Australian continent from Greater India.The boundaries between the sub- basins and many structures within individual sub- basins are considered to have been produced by strike- slip or oblique- slip motion. The offshore North Perth Basin is believed to be a product of transtension, possibly since the earliest phase of rifting. This has culminated in separation and seafloor spreading by oblique extension along the Wallaby Fracture Zone to form a transform passive continental margin.This style of rifting and extension has produced relatively thin syn- rift sequences, some of which have been either partly or completely removed by erosion. While the source- rock potential of the syn- rift phase is limited, post- rift marine transgressional phases and coal measures do provide adequate and relatively widespread source rocks for hydrocarbon generation. Differences in the timing of rifting across the basin have resulted in a maturation pattern whereby mature sediments become younger to the west.


1987 ◽  
Vol 27 (1) ◽  
pp. 245
Author(s):  
J.L. Cosgrove

Natural gas has been discovered in 22 fields in the Central Eromanga and Cooper Basins of southwestern Queensland in the area comprised by ATP 259P. Proved, probable and possible reserves in excess of 36 × 109 m3 (1.27 TCF) are located in four discrete structural provinces. Fluvial sandstones of the Early Permian Patchawarra Formation and Late Permian Toolachee Formation contain the majority of the reserves. Minor amounts of gas are reservoired in the Early Permian Epsilon Formation, the Early-Middle Triassic Nappamerri Formation and the Early Jurassic Hutton Sandstone and Birkhead Formation. Considerable gas-liquids reserves are also found in these reservoirs.Existing reserves are located primarily in structural traps although lithofacies variations are widely recognised, particularly in the Patchawarra Formation, indicating both new play opportunities and difficulties in assessing the undiscovered gas potential of the permit. Additional gas potential is identified in flank areas of the more prominent structural axes such as the Jackson-Wackett-Innamincka Trend in fault-bounded, pinchout and sub-unconformity trapping configurations.More than 200 prospects and leads are identified with the potential to entrap approximately 51 × 109 m3 (1.80 TCF) of gas on an unrisked basis. When combined with reserves from established fields, the ultimate potential of the ATP is assessed as 87 × 109 m3 (8.10 TCF).Despite the very high success rate of previous exploration and appraisal programs, the ultimate gas potential of the Queensland portion of both the Cooper and Eromanga Basins has been only partially addressed. Exploration and appraisal programs providing future additions to proved and probable reserves are considered low risk and are dependent upon an agreement with the Queensland government that would enable the ATP holders to produce and sell gas interstate.


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