The stratigraphy of the Nicola Group in the Hedley district, British Columbia, and the chemistry of its intrusions and Au skarns

1996 ◽  
Vol 33 (8) ◽  
pp. 1105-1126 ◽  
Author(s):  
G. E. Ray ◽  
I. C. L. Webster ◽  
G. L. Dawson
Keyword(s):  
British Columbia ◽  
Oxidation State ◽  
Sedimentary Facies ◽  
Island Arc ◽  
Quartz Diorite ◽  
Late Triassic ◽  
Nickel Plate ◽  
Shallow Marine ◽  
Tectonically Active ◽  
Volcaniclastic Rocks

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).

Revised stratigraphy of the Takla Group, north-central British Columbia

1977 ◽  
Vol 14 (2) ◽  
pp. 318-326 ◽  
Author(s):  
J. W. H. Monger ◽  
B. N. Church
Keyword(s):  
British Columbia ◽  
Sedimentary Rocks ◽  
Lower Jurassic ◽  
Upper Triassic ◽  
Late Triassic ◽  
North Central ◽  
Volcaniclastic Rocks ◽  
Jurassic Rocks

The Takla Group of north-central British Columbia as originally defined contained volcanic and sedimentary rocks of Late Triassic and Jurassic ages. As redefined herein, it consists of three formations in the McConnell Creek map-area. Lowest is the Dewar Formation, composed of argillite and volcanic sandstone that is largely the distal equivalent of basic flows and coarse volcaniclastic rocks of the Savage Mountain Formation. These formations are overlain by the volcaniclastic, basic to intermediate Moosevale Formation. These rocks are Upper Triassic (upper Karnian and lower Norian). They are unconformably overlain by Lower Jurassic rocks of the Hazelton Group.

scholarly journals Dinoflagellate cysts from the Upper Triassic (Norian) of northeastern Iran

2008 ◽  
Vol 27 (2) ◽  
pp. 125-134 ◽  
Author(s):  
Ebrahim Ghasemi-Nejad ◽  
Martin J. Head ◽  
Maryam Zamani
Keyword(s):  
World Wide ◽  
Sedimentary Facies ◽  
Upper Triassic ◽  
Late Triassic ◽  
Dinoflagellate Cysts ◽  
Shallow Marine ◽  
Marine Deposits ◽  
Northwest Europe ◽  
Near Shore ◽  
Early Late

Abstract. Upper Triassic (Norian) strata of the Miankuhi Formation in northeastern Iran have been studied palynologically, revealing a diverse but poorly preserved association of dinoflagellate cysts. Based on representatives of the genera Hebecysta, Heibergella, Rhaetogonyaulax and Sverdrupiella, the strata are assigned to the middle of the Hebecysta balmei Zone with an inferred age of early Late Norian. The association shows similarities with assemblages from Australia, New Zealand, Indonesia, Northwest Europe, arctic Canada and Alaska, indicating an interconnection of warm Tethyan waters during the Late Triassic. The occurrence of Sverdrupiella species in the clastic, near-shore marine deposits of Miankuhi, and their presence in similar sedimentary facies world-wide, indicate that this genus was well adapted to clastic shallow-marine environments.

scholarly journals A review of Palaeozoic and Mesozoic tetrapods from Greenland

2018 ◽  
Vol 66 ◽  
pp. 21-46 ◽  
Author(s):  
Marco Marzola ◽  
Octávio Mateus ◽  
Jesper Milàn ◽  
Lars B. Clemmensen
Keyword(s):  
Late Jurassic ◽  
Early Jurassic ◽  
Late Carboniferous ◽  
Late Triassic ◽  
Late Devonian ◽  
Early Triassic ◽  
Shallow Marine ◽  
East Greenland ◽  
Marine Deposits ◽  
Theropod Dinosaurs

This article presents a synthesis of Palaeozoic and Mesozoic fossil tetrapods from Greenland, including an updated review of the holotypes and a new photographic record of the main specimens. All fossil tetrapods found are from East Greenland, with at least 30 different known taxa: five stem tetrapods (Acanthostega gunnari, Ichthyostega eigili, I. stensioi, I. watsoni, and Ymeria denticulata) from the Late Devonian of the Aina Dal and Britta Dal Formations; four temnospondyl amphibians (Aquiloniferus kochi, Selenocara groenlandica, Stoschiosaurus nielseni, and Tupilakosaurus heilmani) from the Early Triassic of the Wordie Creek Group; two temnospondyls (Cyclotosaurus naraserluki and Gerrothorax cf. pulcherrimus), one testudinatan (cf. Proganochelys), two stagonolepids (Aetosaurus ferratus and Paratypothorax andressorum), the eudimorphodontid Arcticodactylus, undetermined archosaurs (phytosaurs and both sauropodomorph and theropod dinosaurs), the cynodont Mitredon cromptoni, and three mammals (Haramiyavia clemmenseni, Kuehneotherium, and cf. ?Brachyzostrodon), from the Late Triassic of the Fleming Fjord Formation; one plesiosaur from the Early Jurassic of the Kap Stewart Formation; one plesiosaur and one ichthyosaur from the Late Jurassic of the Kap Leslie Formation, plus a previously unreported Late Jurassic plesiosaur from Kronprins Christian Land. Moreover, fossil tetrapod trackways are known from the Late Carboniferous (morphotype Limnopus) of the Mesters Vig Formation and at least four different morphologies (such as the crocodylomorph Brachychirotherium, the auropodomorph Eosauropus and Evazoum, and the theropodian Grallator) associated to archosaurian trackmakers are known from the Late Triassic of the Fleming Fjord Formation. The presence of rich fossiliferous tetrapod sites in East Greenland is linked to the presence of well-exposed continental and shallow marine deposits with most finds in terrestrial deposits from the Late Devonian and the Late Triassic.

A new genus of ichthyosaur from the Late Triassic Pardonet Formation of British Columbia: bridging the Triassic Jurassic gap

2001 ◽  
Vol 38 (6) ◽  
pp. 983-1002 ◽  
Author(s):  
Elizabeth L Nicholls ◽  
Makoto Manabe
Keyword(s):  
British Columbia ◽  
Type Species ◽  
New Genus ◽  
Late Triassic ◽  
Unique Combination ◽  
Type Specimens ◽  
Nomen Dubium ◽  
The Family ◽  
Large Diamond

Both the genus Shastasaurus and the family Shastasauridae have long been hard to define due to the fragmentary nature of the type specimens. Consequently, recent interpretations of the genus have been based almost entirely on Shastasaurus neoscapularis from the Late Triassic Pardonet Formation of British Columbia. Two new specimens of this taxon, from Pink Mountain, British Columbia, demonstrate that it does not belong in the genus Shastasaurus. This paper describes the new specimens, and refers the species to Metashastasaurus gen nov. Post-cranially, the skeleton of Metashastasaurus resembles that of shastasaurids, differing primarily only in the shape of the scapula and fibula. However, the skull has a unique combination of characters, including large diamond-shaped frontals that enter the supratemporal fenestrae, and very narrow posterior extensions of the nasals, which contact the postfrontals. It also differs from the skull of Shastasaurus in the presence of both a parietal ridge and postparietal shelf. This is a combination of derived characters previously known only in Jurassic forms. The front limb has four proximal carpals and four digits, indicating that previous reconstructions were based on incomplete material. Shastasaurus pacificus Merriam 1895, the type species of the genus Shastasaurus, must be considered a nomen dubium, making the genus Shastasaurus invalid. Until this problem is clarified, the use of the generic name Shastasaurus should be restricted to Merriam's type specimens, of which only Shastasaurus alexandrae and Shastasaurus osmonti are based on adequate material.

Gold skarn mineralization and fluid evolution in the Nickel Plate Deposit, British Columbia

1992 ◽  
Vol 87 (6) ◽  
pp. 1541-1565 ◽  
Author(s):  
Art D. Ettlinger ◽  
Lawrence D. Meinert ◽  
Gerry E. Ray
Keyword(s):  
British Columbia ◽  
Nickel Plate ◽  
Fluid Evolution

Nature and origin of the Triassic volcanism in Albania and Othrys: a key to understanding the Neotethys opening?

2008 ◽  
Vol 179 (4) ◽  
pp. 411-425 ◽  
Author(s):  
Philippe Monjoie ◽  
Henriette Lapierre ◽  
Artan Tashko ◽  
Georges H. Mascle ◽  
Aline Dechamp ◽  
...  
Keyword(s):  
Eastern Mediterranean ◽  
Volcanic Rocks ◽  
Island Arc ◽  
Late Triassic ◽  
Central Mediterranean ◽  
Crustal Component ◽  
Sw Turkey ◽  
Wide Range ◽  
Back Arc ◽  
Island Basalt

AbstractTriassic volcanic rocks, stratigraphically associated with pelagic or reef limestones, are tectonically juxtaposed with Mesozoic ophiolites in the Tethyan realm. From the central (Dinarides, Hellenides) and eastern Mediterranean (Antalya, Troodos, Baër Bassit) to the Semail nappes (Oman), they occur either associated to the tectonic sole of the ophiolitic nappes or as a distinct tectonic pile intercalated between the ophiolites and other underthrust units. In the Dinaro-Hellenic belt, the Pelagonian units represent the lower plate, which is underthrust beneath the ophiolites. Middle to Late Triassic volcanic sequences are interpreted as the eastern flank of the Pelagonian platform and are therefore considered as a distal, deep-water part of the Pelagonian margin.The Triassic volcanics from Albania and Othrys are made up of basaltic pillowed and massive flows, associated locally with dolerites and trachytes. New elemental, Nd and Pb isotopic data allow to recognize four types of volcanic suites: (1) intra-oceanic alkaline and tholeiitic basalts, (2) intra-oceanic arc-tholeiites, (3) back-arc basin basalts, (4) calc-alkaline mafic to felsic rocks. Nd and Pb isotopic initial ratios suggest that the within-plate volcanic rocks were derived from an enriched oceanic island basalt type mantle source, devoid of any continental crustal component. The lower εNd value of the trachyte could be due to assimilation of oceanic altered crust or sediments in a shallow magma chamber. Island arc tholeiites and back-arc basin basalts have a similar wide range of εNd. The absence of Nb negative anomalies in the back-arc basin basalts suggests that the basin floored by these basalts was wide and mature. The high Th contents of the island arc tholeiites suggest that the arc volcanoes were located not far away from the continental margin.Albania and Othrys volcanics contrast with the Late Triassic volcanism from eastern Mediterranean (SW Cyprus, SW Turkey), which displays solely features of oceanic within plate suites. The presence of back-arc basin basalts associated with arc-related volcanics in Central Mediterranean indicates that they were close to a still active subduction during the Upper Triassic, while back-arc basins developed, associated with within-plate volcanism, leading to the NeoTethys opening.

Systematics and Paleoecology of Norian (Late Triassic) Bivalves from a Tropical Island Arc: Wallowa Terrane, Oregon

1987 ◽  
Vol 61 (S22) ◽  
pp. 1-83 ◽  
Author(s):  
Cathryn R. Newton ◽  
Michael T. Whalen ◽  
Joel B. Thompson ◽  
Nienke Prins ◽  
David Delalla
Keyword(s):  
North American ◽  
Island Arc ◽  
Late Triassic ◽  
Small Scale ◽  
Long Distance ◽  
Tropical Island ◽  
North American Cordillera ◽  
The North ◽  
Wallowa Terrane ◽  
Hells Canyon

Early Norian silicified bivalves from Hells Canyon in the Wallowa terrane of northeastern Oregon are part of a rich molluscan biota associated with a tropical island arc. The Hells Canyon locality preserves lenses of silicified shells formed as tempestites in a shallow subtidal carbonate environment. These shell assemblages are parautochthonous and reflect local, rather than long-distance, transport. Silicification at this locality involved small-scale replacement of original calcareous microstructures, or small-scale replacement of neomorphosed shells, without an intervening phase of moldic porosity. This incremental replacement of carbonate by silica contrasts markedly with void-filling silicification textures reported previously from silicified Permian bivalve assemblages.The bivalve paleoecology of this site indicates a suspension feeding biota existing on and within the interstices of coral-spongiomorph thickets, and inhabiting laterally adjacent substrates of peloidal carbonate sand. The bivalve fauna is ecologically congruent with the reef-dwelling molluscs associated with Middle Triassic sponge-coral buildups in the Cassian Formation of the Dolomites (Fuersich and Wendt, 1977). Hells Canyon is a particularly important early Norian locality because of the diversity of substrate types and because the site includes many first occurrences of bivalves in the North American Cordillera. These first occurrences include the first documentation of the important epifaunal families Pectinidae and Terquemiidae in Triassic rocks of the North American Cordillera.The large number of biogeographic and geochronologic range extensions discovered in this single tropical Norian biota indicates that use of literature-based range data for Late Triassic bivalves may be very hazardous. Many bivalve taxa formerly thought to have gone extinct in Karnian time have now been documented from Norian strata in this arc terrane. These range extensions, coupled with the high bivalve species richness of the Hells Canyon site, suggest that the Karnian mass extinction in several literature-based compilations may be an artifact of incomplete sampling. Even for the Norian, present compilations of molluscan extinction may have an unacceptably large artifactual component.Thirty-five bivalve taxa from the Hells Canyon locality are discussed. Of these, seven are new: the mytilid Mysidiella cordillerana n. sp., the limacean Antiquilima vallieri n. sp., the true oyster Liostrea newelli n. sp., the pectinacean Crenamussium concentricum n. gen. and sp., the unioid Cardinioides josephus n. sp., the trigoniacean Erugonia canyonensis n. gen. and sp., and the carditacean Palaeocardita silberlingi n. sp.

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