Rb–Sr dates for granodiorite intrusions on the northeast margin of the Shuswap Metamorphic Complex, Cariboo Mountains, British Columbia

1977 ◽  
Vol 14 (7) ◽  
pp. 1690-1695 ◽  
Author(s):  
Lee C. Pigage
Keyword(s):  
British Columbia ◽  
Upper Jurassic ◽  
Upper Triassic ◽  
Time Interval ◽  
Metamorphic Complex ◽  
The North ◽  
Regional Deformation ◽  
Shuswap Metamorphic Complex ◽  
North And South ◽  
Provincial Park

Whole rock Rb–Sr dates of 138 ± 12 Ma (all five whole rocks) and 163 ± 7 Ma were obtained for granodiorite stocks in Wells Gray Provincial Park, Cariboo Mountains, British Columbia. These dates bracket the biotite K–Ar date of 143 ± 14 Ma determined previously by the Geological Survey of Canada. Two biotite – whole rock ± hornblende dates of 119 ± 11 Ma and 77 ± 20 Ma indicate isotopic resetting. Initial 87Sr–86Sr ratios vary from 0.7061 ± 0.0001 to 0.7103 ± 0.0002 for rock and mineral dates.When combined with field relations, these dates restrict regional deformation and metamorphism in this area to the time interval between Upper Triassic and Upper Jurassic. The resetting event was probably Eocene, as shown in other areas along regional strike to the north and south.

Stratigraphic revisions of the Nicola, Cache Creek, and Mount Ida Groups, based on conodont collections from the western margin of the Shuswap Metamorphic Complex, south-central British Columbia

1976 ◽  
Vol 13 (1) ◽  
pp. 44-53 ◽  
Author(s):  
A. V. Okulitch ◽  
B. E. B. Cameron
Keyword(s):  
British Columbia ◽  
Upper Triassic ◽  
Late Triassic ◽  
Metamorphic Complex ◽  
Western Margin ◽  
South Central ◽  
Western Border ◽  
Shuswap Metamorphic Complex

Conodonts have been recovered from highly deformed limestone and calcareous argillite in Palaeozoic and Mesozoic successions near the western border of the Shuswap Metamorphic Complex. Presently known biostratigraphic sequences indicate that the Eagle Bay Formation of the Mount Ida Group is in part Mississippian in age, and likely correlative with the Slide Mountain and Milford Groups. In addition, part of the succession previously mapped as Cache Creek Group in the Vernon area is now known to be Late Triassic in age, and can be correlated with the Sicamous Formation of the Mount Ida Group, the Nicola Group, and the Slocan Group. The Upper Triassic succession was affected by deformation and metamorphism associated with development of the Shuswap Metamorphic Complex.

Devonian Plutonism in South-Central British Columbia

1975 ◽  
Vol 12 (10) ◽  
pp. 1760-1769 ◽  
Author(s):  
Andrew V. Okulitch ◽  
R. K. Wanless ◽  
W. D. Loveridge
Keyword(s):  
British Columbia ◽  
Middle Devonian ◽  
Metamorphic Complex ◽  
Western Margin ◽  
South Central ◽  
Minimum Age ◽  
History Of ◽  
Shuswap Metamorphic Complex

An apparently tabular body of granitoid gneiss, 3 to 5 km wide and more than 70 km long, that lies along the western margin of the Shuswap Metamorphic Complex between Shuswap and Admas Lakes, shows intrusive relationships with Palaeozoic and older rocks and has yielded zircons whose minimum age is 372 Ma. This intrusion, together with other granitoid plutons in the area that appear to be related to it, provide evidence of widespread plutonism during Middle Devonian time near the western edge of the Paleozoic Cordillera geosyncline and necessitate significant revisions in the interpretation of the crustal history of this region.

An asteroid (Echinodermata) faunule from the Oxfordian Swift Formation (Upper Jurassic) of Montana

2016 ◽  
Vol 90 (6) ◽  
pp. 1160-1168
Author(s):  
Daniel B. Blake ◽  
Thomas E. Guensburg
Keyword(s):  
New Genus ◽  
Upper Jurassic ◽  
Wide Distribution ◽  
Time Interval ◽  
New Genus And Species ◽  
The North ◽  
Class Level ◽  
Regional Location ◽  
Favorable Conditions ◽  
Continental Interior

AbstractA new Late Jurassic (Oxfordian) asteroid (Echinodermata) faunule from the Swift Formation of Montana includes representatives of four genera including the new genus and speciesAtalopegaster gundersoni(Stichasteridae),Eokainastersp. indet. (Astropectinidae), an indeterminate probable member of the Goniasteridae, and a species indeterminate beyond the class level. Because of weathering at the outcrop, preservation is poor.Although representing an unusual depositional occurrence, overall faunule composition appears comparable to that found in a similar modern environment. The faunule is comparable in age and regional location to earlier Jurassic asteroid discoveries, suggesting wide distribution during a geologically brief time interval of favorable conditions. Asteroids are only rarely reported from the Mesozoic of the North American continental interior, and co-occurrence of multiple fossil taxa is unusual on a global basis.

Recherches geologiques preliminaires dans le massif du Parnasse (Grece)

1957 ◽  
Vol S6-VII (4-5) ◽  
pp. 571-583 ◽  
Author(s):  
Paul Celet
Keyword(s):  
Upper Triassic ◽  
Stratigraphic Sequence ◽  
The North ◽  
North And South ◽  
East West

Abstract The stratigraphic sequence of the Parnassus massif in Greece begins with coral-bearing upper Triassic dolomites and limestones, which are overlain by a thick series of Mesozoic limestones capped by red shaly marls and sandy Flysch formations. The structure was influenced by the rigidity of the limestone cover, which is faulted and overthrust in slices toward the east-northeast. The massif as a whole is cut by deep east-west-trending faults, along which the large grabens bounding the massif on the north and south were downdropped.

Late Triassic Bivalvia (chiefly Halobiidae and Monotidae) from the Pardonet Formation, Williston Lake area, northeastern British Columbia, Canada

2011 ◽  
Vol 85 (4) ◽  
pp. 613-664 ◽  
Author(s):  
Christopher A. McRoberts
Keyword(s):  
British Columbia ◽  
Sedimentary Basin ◽  
Upper Triassic ◽  
Late Triassic ◽  
Continuous Series ◽  
Lake Area ◽  
North American Cordillera ◽  
The North ◽  
The Subject ◽  
Nearly Continuous

The Upper Triassic of the Williston Lake area of northeastern British Columbia is represented by a nearly continuous series of fossil-rich sediments that were deposited in the Western Canadian Sedimentary Basin in an offshore mid-paleolatitude setting on the western margin of cratonic Pangea. The fossils in this report come primarily from the upper Carnian–upper Norian Pardonet Formation, which has been the subject of numerous paleontologic studies on ammonoids and conodonts, yet has received little attention with regard to its bivalve fauna. Fossil bivalves belonging to the thin-shelled bivalve genera Halobia, Eomonotis, and Monotis dominate the benthic macrofauna and occur within unique shell accumulations that are interpreted to represent oxygen-controlled monospecific paleocommumities that have undergone little post-mortem transportation. Systematic analyses of more than 1,000 individual bivalve specimens resulted in the identification of 25 species-rank taxa, a majority of which belong to the pterioid genus Halobia and the pectinoid genera Eomonotis and Monotis. Of these, four new species are recognized, including 1) upper Carnian Halobia tozeri n. sp. characterized by a unique triangular outline; 2) lowermost Norian Halobia selwyni n. sp. closely related to H. beyrichi and first appearing with H. austriaca which is proposed as a potential datum for the Carnian–Norian boundary; 3) Norian Meleagrinella mclearni n. sp., a new name for previously identified species; and 4) upper Norian Otaparia norica n. sp. which has a delicate thin shell, unique outline, and fine ornament. A revised and refined biochronology of Upper Triassic Bivalvia (chiefly Halobiidae and Monotidae) integrated with conodont and ammonoid zones and standard Triassic stages is presented for the Upper Triassic of the Williston Lake area and permits enhanced correlation to coeval faunas elsewhere in the North American Cordillera, and to the Boreal, Panthalassan and Tethyan faunal realms.

Precambrian Zircon Age of Orthogneiss in the Shuswap Metamorphic Complex, British Columbia

1975 ◽  
Vol 12 (2) ◽  
pp. 326-332 ◽  
Author(s):  
R. K. Wanless ◽  
J. E. Reesor
Keyword(s):  
British Columbia ◽  
Metamorphic Complex ◽  
Gneiss Dome ◽  
Zircon Age ◽  
Core Zone ◽  
The Core ◽  
Basement Rocks ◽  
Proterozoic Basement ◽  
Shuswap Metamorphic Complex ◽  
Age Determinations

Pb-U age determinations carried out on zircon from granodiorite gneiss of the core zone of Thor-Odin gneiss dome have provided isotopic evidence for involvement of Proterozoic basement rocks in the Mesozoic structures of the Shuswap Metamorphic Complex. The study has revealed that the zircons originally crystallized [Formula: see text] ago and suffered an episodic loss of lead [Formula: see text] ago.

The Beryl Field, Block 9/13, UK North Sea

1991 ◽  
Vol 14 (1) ◽  
pp. 33-42 ◽  
Author(s):  
C. A. Knutson ◽  
I. C. Munro
Keyword(s):  
North Sea ◽  
Middle Jurassic ◽  
Oil And Gas ◽  
Upper Jurassic ◽  
Lower Jurassic ◽  
Gas Production ◽  
Upper Triassic ◽  
Oil Field ◽  
Oil And Gas Production ◽  
The North

AbstractThe Beryl Field, the sixth largest oil field in the UK sector of the North Sea, is located within Block 9/13 in the west-central part of the Viking Graben. The block was awarded in 1971 to a Mobil operated partnership and the 9/13-1 discovery well was drilled in 1972. The Beryl A platform was emplaced in 1975 and the Beryl B platform in 1983. To date, ninety-five wells have been drilled in the field, and drilling activity is anticipated into the mid-1990s.Commercial hydrocarbons occur in sandstone reservoirs ranging in age from Upper Triassic to Upper Jurassic. Structurally, the field consists of a NNE orientated horst in the Beryl A area and westward tilted fault blocks in the Beryl B area. The area is highly faulted and complicated by two major and four minor unconformities. The seal is provided by Upper Jurassic shales and Upper Cretaceous marls.There are three prospective sedimentary sections in the Beryl Field ranked in importance as follows: the Middle Jurassic coastal deltaic sediments, the Upper Triassic to Lower Jurassic continental and marine sediments, and the Upper Jurassic turbidites. The total ultimate recovery of the field is about 800 MMBBL oil and 1.6 TCF gas. As of December 1989, the field has produced nearly 430 MMBBL oil (primarily from the Middle Jurassic Beryl Formation), or about 50% of the ultimate recovery. Gas sales are scheduled to begin in the early 1990s. Oil and gas production is forecast until licence expiration in 2018.The Beryl Fields is located 215 miles northeast of Aberdeen, about 7 miles from the United Kingdom-Norwegian boundary. The field lies within Block 9/13 and covers and area of approximately 12 000 acres in water depths ranging from 350-400 ft. Block 9/13 contains several hydrocarbon-bearing structures, of which the Beryl Fields is the largest (Fig. 1). The field is subdivided into two producing areas: the Beryl Alpha area which includes the initial discovery well, and the Beryl Bravo area located to the north. The estimated of oil originally in place is 1400 MMBBL for Beryl A and 700 MMBBL for Beryl B. The fiel has combined gas in place of 2.8 TCF, consisting primarily of solution gas. Hydrocarbon accumulations occur in six reservoir horizons ranging in age from Upper Triassic to Upper Jurassic. The Middle Jurassic (Bathonian to Callovian) age Beryl Formation is the main reservoir unit and contains 78% of the total ultimate recovery.The field was named after Beryl Solomon, the wife of Charles Solomon, who was president of Mobil Europe in 1972 when the field was discovered. The satellite fields in Block 9/13 (Nevis, Ness and Linnhe) are named after Scottish lochs.

Paleomagnetic Results from the Jurassic Topley Intrusions near Endako, British Columbia

1973 ◽  
Vol 10 (7) ◽  
pp. 1099-1108 ◽  
Author(s):  
D. T. A. Symons
Keyword(s):  
British Columbia ◽  
Lower Cretaceous ◽  
Remanent Magnetization ◽  
Upper Jurassic ◽  
Pole Position ◽  
Upper Triassic ◽  
Polar Wander ◽  
Quartz Monzonite ◽  
Reversed Polarity ◽  
North American Craton

The Upper Jurassic Topley Intrusions intrude rocks of the tectonically stable Interior Plateau in central British Columbia. A stable primary remanent magnetization of both normal and reversed polarity was isolated after a.f. demagnetization in 19 of 22 sites (109 cores; 208 specimens) representing several of the plutonic units present in this sialic complex of quartz monzonite affinity near Endako, B.C. The unit mean remanence directions support some petrological correlations suggested by Carr, Bright, and White et al., but do not support others. The pole position derived from 13 sites representing 6 plutonic units with a K–Ar radiomelric age of 139 ± 4 m.y. (White et al.) is 128.6 °E, 70.0 °N(δm = 14.4°; δp = 11.4°). This position indicates a smooth polar wander path during the Jurassic between the well defined Upper Triassic and Lower Cretaceous pole positions. It also indicates that the northern Interior Plateau has not been tectonically rotated or translated since emplacement relative to the stable North American craton.

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