Cambrian geography and sedimentation in the central Cordilleran region

Deiss, Charles

doi:10.1130/gsab-52-1085

Cited by 25 publications

(13 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is conformably overlain by the Cathedral Formation. Distinct trilobite faunas, including the Plagiura–Albertalla zone in the Main and Front Ranges indicated that the Mount Whyte and Cathedral formations were deposited during the Series 2 (516.0 to 513.0 Ma; Deiss, ; Collom et al ., ; Fig. ), which is taken to be the assumed age of the Mount Whyte Formation in this study.…”

Section: Geological Backgroundmentioning

confidence: 99%

Evaluating new fault‐controlled hydrothermal dolomitization models: Insights from the Cambrian Dolomite, Western Canadian Sedimentary Basin

et al. 2020

View full text Add to dashboard Cite

Fault‐controlled hydrothermal dolomitization in tectonically complex basins can occur at any depth and from different fluid compositions, including ‘deep‐seated’, ‘crustal’ or ‘basinal’ brines. Nevertheless, many studies have failed to identify the actual source of these fluids, resulting in a gap in our knowledge on the likely source of magnesium of hydrothermal dolomitization. With development of new concepts in hydrothermal dolomitization, the study aims in particular to test the hypothesis that dolomitizing fluids were sourced from either seawater, ultramafic carbonation or a mixture between the two by utilizing the Cambrian Mount Whyte Formation as an example. Here, the large‐scale dolostone bodies are fabric‐destructive with a range of crystal fabrics, including euhedral replacement (RD1) and anhedral replacement (RD2). Since dolomite is cross‐cut by low amplitude stylolites, dolomitization is interpreted to have occurred shortly after deposition, at a very shallow depth (<1 km). At this time, there would have been sufficient porosity in the mudstones for extensive dolomitization to occur, and the necessary high heat flows and faulting associated with Cambrian rifting to transfer hot brines into the near surface. While the δ18Owater and 87Sr/86Sr ratios values of RD1 are comparable with Cambrian seawater, RD2 shows higher values in both parameters. Therefore, although aspects of the fluid geochemistry are consistent with dolomitization from seawater, very high fluid temperature and salinity could be suggestive of mixing with another, hydrothermal fluid. The very hot temperature, positive Eu anomaly, enriched metal concentrations, and cogenetic relation with quartz could indicate that hot brines were at least partially sourced from ultramafic rocks, potentially as a result of interaction between the underlying Proterozoic serpentinites and CO2‐rich fluids. This study highlights that large‐scale hydrothermal dolostone bodies can form at shallow burial depths via mixing during fluid pulses, providing a potential explanation for the mass balance problem often associated with their genesis.

show abstract

Section: Geological Backgroundmentioning

confidence: 99%

Evaluating new fault‐controlled hydrothermal dolomitization models: Insights from the Cambrian Dolomite, Western Canadian Sedimentary Basin

et al. 2020

View full text Add to dashboard Cite

show abstract

“…3), a northeast-striking, thick, Cryogenian-Paleozoic sedimentary succession was deposited northwest of the down-to-the-northwest St. Mary-Moyie basinbounding fault system (Norris and Price, 1966;Lis and Price, 1976;Price and Sears, 2000). Paired to the southeast was the recurrently emergent Montania arch (Deiss, 1941;Lis and Price, 1976;Benvenuto and Price, 1979;Bush, 1991;Price and Sears, 2000). This structural system controlled the miogeoclinal segment in northeastern Washington and British Columbia.…”

Section: Extensional Setting Of Margin Segmentsmentioning

confidence: 99%

Geometry of the Neoproterozoic and Paleozoic rift margin of western Laurentia: Implications for mineral deposit settings

2008

View full text Add to dashboard Cite

The U.S. and Canadian Cordilleran miogeocline evolved during several phases of Cryogenian-Devonian intracontinental rifting that formed the western margin of Laurentia. Recent fi eld and dating studies across central Idaho and northern Nevada result in identifi cation of two segments of the rift margin. Resulting interpretations of rift geometry in the northern U.S. Cordillera are compatible with interpretations of northweststriking asymmetric extensional segments subdivided by northeast-striking transform and transfer segments. The new interpretation permits integration of miogeoclinal segments along the length of the western North American Cordillera. For the U.S. Cordillera, miogeoclinal segments include the St. Mary-Moyie transform, eastern Washingtoneastern Idaho upper-plate margin, Snake River transfer, Nevada-Utah lower-plate margin, and Mina transfer. The rift is orthogonal to most older basement domains, but the location of the transform-transfer zones suggests control of them by basement domain boundaries. The zigzag geometry of reentrants and promontories along the rift is paralleled by salients and recesses in younger thrust belts and by segmentation of younger extensional domains. Likewise, transform-transfer zones localized subsequent transcurrent structures and igneous activity. Sediment-hosted mineral deposits trace the same zigzag geometry along the margin. Sedimentary exhalative (sedex) Zn-Pb-Ag ± Au and barite mineral deposits formed in continental-slope rocks during the Late Devonian-Mississippian and to a lesser degree, during the Cambrian-Early Ordovician. Such deposits formed during episodes of renewed extension along miogeoclinal segments. Carbonate-hosted Mississippi Valleytype (MVT) Zn-Pb deposits formed in structurally reactivated continental shelf rocks during the Late Devonian-Mississippian and Mesozoic due to reactivation of preexisting structures. The distribution and abundance of sedex and MVT deposits are controlled by the polarity and kinematics of the rift segment. Locally, discrete mineral belts parallel secondary structures such as rotated crustal blocks at depth that produced sedimentary subbasins and conduits for hydrothermal fl uids. Where the miogeocline was overprinted by Mesozoic and Cenozoic deformation and magmatism, igneous rock-related mineral deposits are common.

show abstract

“…Some geologists ( Schuchert, 1910;Deiss, 1941) have suggested that a land area ("Cascadia") with a sedimentary and crystalline terrane lay west of the Cordilleran geosyncline in early Paleozoic time and was the source of the detrital material that was deposited in the geosyncline. More recently, Kay ( 1951, p. 4) rejected the idea of Cascadia, but indicated the possibility that the western part of the Cordilleran geosyncline contained linear tectonic and volcanic islands that contributed debris, largely volcanic, to the geosyncline.…”

Section: Paleogeographymentioning

confidence: 99%

Upper Precambrian and lower Cambrian strata in the southern Great Basin, California and Nevada

Stewart¹

1970

Professional Paper

141

217

View full text Add to dashboard Cite

Cambrian geography and sedimentation in the central Cordilleran region

Cited by 25 publications

References 0 publications

Evaluating new fault‐controlled hydrothermal dolomitization models: Insights from the Cambrian Dolomite, Western Canadian Sedimentary Basin

Evaluating new fault‐controlled hydrothermal dolomitization models: Insights from the Cambrian Dolomite, Western Canadian Sedimentary Basin

Geometry of the Neoproterozoic and Paleozoic rift margin of western Laurentia: Implications for mineral deposit settings

Upper Precambrian and lower Cambrian strata in the southern Great Basin, California and Nevada

Contact Info

Product

Resources

About