Mantle Exhumation in an Early Paleozoic Passive Margin, Northern Cordillera, Yukon

2003 ◽  
Vol 111 (3) ◽  
pp. 313-327 ◽  
Author(s):  
D. Canil ◽  
S. T. Johnston ◽  
K. Evers ◽  
J. G. Shellnutt ◽  
R. A. Creaser
Keyword(s):  
Passive Margin ◽  
Early Paleozoic ◽  
Mantle Exhumation

scholarly journals Early Paleozoic rifting and reactivation of a passive-margin rift: Insights from detrital zircon provenance signatures of the Potsdam Group, Ottawa graben: Comment

2019 ◽  
Vol 131 (3-4) ◽  
pp. 695-698
Author(s):  
Ed Landing ◽  
Osman Salad Hersi ◽  
Lisa Amati ◽  
Stephen R. Westrop ◽  
David A. Franzi
Keyword(s):  
Detrital Zircon ◽  
Passive Margin ◽  
Early Paleozoic

The initiation of the early Paleozoic Cordilleran miogeocline: evidence from the uppermost Proterozoic – Lower Cambrian Hamill Group of southeastern British Columbia

1988 ◽  
Vol 25 (1) ◽  
pp. 1-19 ◽  
Author(s):  
William J. Devlin ◽  
Gerard C. Bond
Keyword(s):  
British Columbia ◽  
Lower Cambrian ◽  
Direct Evidence ◽  
Thermal Anomaly ◽  
Passive Margin ◽  
Early Paleozoic ◽  
Upper Proterozoic ◽  
Windermere Supergroup ◽  
Depositional Setting ◽  
Thermal Subsidence

The uppermost Proterozoic–Lower Cambrian Hamill Group of southeastern British Columbia contains geologic evidence for a phase of extensional tectonism that led directly to the onset of thermally controlled subsidence in the Cordilleran miogeocline. Moreover, the Hamill Group contains the sedimentological record of the passage of the ancient passive margin from unstable tectonic conditions associated with rifting and (or) the earliest phases of thermal subsidence to post-rift conditions characterized by stabilization of the margin and dissipation of the thermal anomaly generated during the rift phase (the rift to post-rift transition). Widespread uplift that occurred prior to and during the deposition of the lower Hamill Group is indicated by an unconformable relation with the underlying Windermere Supergroup and by stratigraphic relations between Middle and Upper Proterozoic strata and unconformably overlying upper Lower Cambrian quartz arenites (upper Hamill Group) in the southern borderlands of the Hamill basin. In addition, the coarse grain size, the feldspar content, the depositional setting, and the inferred provenance of the lower Hamill Group are all indicative of the activation of basement sources along the margins of the Hamill basin. Geologic relations within the Hamill Group that provide direct evidence for extensional tectonism include the occurrence of thick sequences of mafic metavolcanics and rapid vertical facies changes that are suggestive of syndepositional tectonism.Evidence of extensional tectonism in the Hamill Group directly supports inferences derived from tectonic subsidence analyses that indicate the rift phase that immediately preceded early Paleozoic post-rift cooling could not have occurred more than 10–20 Ma prior to 575 ± 25 Ma. These data, together with recently reported isotopic data that suggest deposition of the Windermere Supergroup began ~730–770 Ma, indicate that the rift-like deposits of the Windermere Supergroup are too old to represent the rifting that led directly to the deposition of the Cambro-Ordovician post-rift strata. Instead, Windermere sedimentation was apparently initiated by an earlier rift event, probably of regional extent, that was part of a protracted, episodic rift history that culminated with continental breakup in the latest Proterozoic – Early Cambrian.

Volcanism on the passive margin of Laurentia: an early Paleozoic analogue of Cretaceous volcanism on the northeastern American margin: Reply

1990 ◽  
Vol 27 (11) ◽  
pp. 1552-1554 ◽  
Author(s):  
Stephen Kumarapeli ◽  
Karen St. Seymour ◽  
Hillar Pintson ◽  
Elizabeth Hasselgren
Keyword(s):  
Passive Margin ◽  
Early Paleozoic ◽  
Cretaceous Volcanism

The passive margin of northern Gondwana during Early Paleozoic: Evidence from the central Tibet Plateau

2020 ◽  
Vol 78 ◽  
pp. 126-140 ◽  
Author(s):  
Yiming Liu ◽  
Sanzhong Li ◽  
M. Santosh ◽  
Huahua Cao ◽  
Shengyao Yu ◽  
...  
Keyword(s):  
Passive Margin ◽  
Tibet Plateau ◽  
Early Paleozoic ◽  
Central Tibet

scholarly journals Nature and Origin of Mineralizing Fluids in Hyperextensional Systems: The Case of Cretaceous Mg Metasomatism in the Pyrenees

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Benoît Quesnel ◽  
Marie-Christine Boiron ◽  
Michel Cathelineau ◽  
Laurent Truche ◽  
Thomas Rigaudier ◽  
...  
Keyword(s):  
Continental Crust ◽  
Fluid Inclusions ◽  
High Salinity ◽  
Shear Zones ◽  
Passive Margin ◽  
Ore Deposit ◽  
Brine Migration ◽  
Mantle Exhumation ◽  
Seawater Concentration ◽  
Isotope Analyses

During the Albian, the hyperextension of the Pyrenean passive margin led to a hyperthinning of the continental crust and the subsequent subcontinental mantle exhumation. The giant Trimouns talc-chlorite deposit represents the most prominent occurrence of Albian metasomatism in the Pyrenees, with the occurrence of the largest talc deposit worldwide. Consequently, this deposit, which is located on a fault zone and a lithological contact, represents one of the major drains at the scale of the Pyrenees and one of the best geological targets in order to determine the origin(s) of the fluid(s) that circulated during this period. Talc-chlorite ore is characterized by the presence of brines trapped in dolomite, quartz, and calcite fluid inclusions in the vicinity of the talc-rich zone. Considered as being responsible for the formation of talc, these fluids may be interpreted in several ways: (i) primary brines expelled from Triassic evaporites, (ii) secondary brines produced through halite leaching by diagenetic/metamorphic fluids, and (iii) brines derived from seawater serpentinization of mantle rocks. Stable isotope analyses (δ13C, δ18O, δD, and δ37Cl) and Cl/Br ratio measurements in fluid inclusions and their host minerals were carried out in order to determine the origin of the fluid(s) involved in the formation of the ore deposit. The data are consistent with a primary brine origin for the mineralizing fluid, which could have been expelled from the Triassic levels. Other hypotheses have been tested, for example, the production of brines via the seawater concentration during serpentinization. The geochemical proxies used in this study provide equivocal results. The first hypothesis is by far the most realistic one considering the numerous occurrences of Trias formations nearby, their deformation during the extension, and the drainage of the expulsed brines as evidenced by the high-salinity fluid inclusions found all around the deposit. Alternatively, the exhumation of the mantle is considered as a major source of heat and stress that favored brine migration along the major shear zones. Our results fit well with brine circulation in a hyperextensional geodynamic context, which is related to the formation of the talc-chlorite ore, the thinning of the continental crust, and the exhumation of the subcontinental mantle, in accordance with recent works.

Fluid circulations in response to mantle exhumation at the passive margin setting in the north Pyrenean zone, France

2018 ◽  
Vol 112 (5) ◽  
pp. 647-670 ◽  
Author(s):  
B. Corre ◽  
P. Boulvais ◽  
M. C. Boiron ◽  
Y. Lagabrielle ◽  
L. Marasi ◽  
...  
Keyword(s):  
Passive Margin ◽  
Margin Setting ◽  
The North ◽  
Mantle Exhumation
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