The Siberian Connection: A case for Precambrian separation of the North American and Siberian cratons

Sears, James W.; Price, Raymond A.

doi:10.1130/0091-7613(1978)6<267:tscacf>2.0.co;2

Cited by 160 publications

(48 citation statements)

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“…The rocks underlying the alkaline province belong to the Middle Proterozoic Purcell Supergroup and comprise primary clastic and carbonate rocks >20 km thick deposited between 1700 and 780 Ma (Monger et al, 1972;Sears and Price, 1978;Monger and Price, 1979). Late Proterozoic (780-570 Ma) strata comprising gritty feldspathic sandstones, locally also volcanic rocks, and carbonate rocks lie unconformably over the Purcell Supergroup.…”

Section: Geological Settingmentioning

confidence: 99%

The Nature and Origin of the REE Mineralization in the Wicheeda Carbonatite, British Columbia, Canada

et al. 2016

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In response to rising demand of the rare earth elements (REE), recent exploration of the British Columbia alkaline province has identified the Wicheeda Carbonatite, which contains an estimated 11.3 million tons of light REE-enriched ore grading 1.95 wt.% TREO, to be the highest-grade prospect known in British Columbia. However, research of the deposit is restricted to one paper describing mineralization in carbonatite dikes adjacent to the main plug. This study describes the nature and origin of REEmineralization in the Wicheeda plug.The carbonatite was emplaced in metasedimentary limestone and argillaceous limestone belonging to the Kechika Group, which has been altered to potassic fenite immediately adjacent to the carbonatite and to sodic fenite at greater distances from it. The carbonatite comprises a ferroan dolomite core, which passes outwards gradationally into calcite carbonatite. Three texturally distinct varieties of dolomite have been recognized. Un modèle est proposé dans lequel la carbonatite calcitique est la phase magmatique la plus précoce. Cette phase a atteint la saturation en niobium très tôt, entrainant la précipitation du pyrochlore. Le magma a évolué plus tardivement vers une composition de carbonatite dolomitique qui, lors de son refroidissement, a exsolvé un fluide aquocarbonique altérant les métasédiments de Kechika en fénite potassique et se mélangeant avec les eaux formationelles, plus distales, pour produire les fénites sodiques.Le fluide aquo-carbonique a mobilisé et transporté les ETR sous la forme de complexes chlorurés, au sein de la porosité et des fractures de la carbonatite dolomitique. A la suite des interactions fluide-roche prolongées, les ETR ont précipité du fait du refroidissement et de l'augmentation du pH ; la présence d'apatite a entrainé la formation de monazite-(Ce). La concentration hydrothermale a permis une répartition homogène des teneurs, avec la carbonatite dolomitique contenant dans son ensemble plus de 1 % TREO, faisant de Wicheeda un gisement très attrayant. Contributions of AuthorsThis thesis has been written in manuscript format in accordance with the regulations put

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Section: Geological Settingmentioning

confidence: 99%

The Nature and Origin of the REE Mineralization in the Wicheeda Carbonatite, British Columbia, Canada

et al. 2016

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“…Unfortunately, the Late Proterozoic glaciations are poorly dated and it is difficult to compare directions from the igneous bodies with those from the sedimentary record. For the purpose of these paleogeographic reconstructions, we have placed the Cordilleran margin of Laurentia adjacent to the northeastern margin of the Siberian Platform as suggested by Sears and Price (1978).…”

Section: Siberiamentioning

confidence: 99%

“…Finally, the position of North America (Laurentia) is more problematic. For lack of better constraints, we fit the Cordilleran margin of North America adjacent to the northeast margin of Siberia, as was suggested by Sears and Price (1978) and used extensively in the reconstructions of Piper (1983Piper ( , 1986. This is reasonably consistent with the lithologic and paleomagnetic constraints, although the timing of the rifting on the Cordilleran margin is not well constrained.…”

Section: /3a Gondwanamentioning

confidence: 99%

A Paleogeographic Model for Vendian and Cambrian Time

Kirschvink

1992

The Proterozoic Biosphere

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“…Thus, the aulacogen would have been connected on the west to a Middle Proterozoic continental margin, whose location and orientation remain unknown. Presumably the same stratigraphic evidence led Burke and Dewey (1973), Sears and Price (1978), Welsh (1979, p. 93), Sears and others (1982, p. 990), and Gries (1983, p. 11) to call the Uinta trough an aulacogen, although these reports cite no evidence to justify this inference.…”

Section: Uinta Aulacogen Evidence For Existence Of the Aulacogenmentioning

confidence: 95%

“…Stewart and Poole (1974) reported an oral suggestion by Paul Hoffman in 1971 that the Uinta trough might have been a Proterozoic aulacogen. Burke and Dewey (1973), Crittenden and Wallace (1973), and Sears and Price (1978) regarded the trough as one of several aulacogens in western North America that formed as precursors to the Late Proterozoic rifting.…”

Section: Pre-cenozoic Structures Introductionmentioning

confidence: 99%

Segmentation of the Wasatch fault zone, Utah — Summaries, analyses, and interpretations of geological and geophysical data

Wheeler¹,

Krystinik²

1988

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The Siberian Connection: A case for Precambrian separation of the North American and Siberian cratons

Cited by 160 publications

References 0 publications

The Nature and Origin of the REE Mineralization in the Wicheeda Carbonatite, British Columbia, Canada

The Nature and Origin of the REE Mineralization in the Wicheeda Carbonatite, British Columbia, Canada

A Paleogeographic Model for Vendian and Cambrian Time

Segmentation of the Wasatch fault zone, Utah — Summaries, analyses, and interpretations of geological and geophysical data

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