2.01-Ga Kennedy dike swarm, southeastern Wyoming: Record of a rifted margin along the southern Wyoming province

2000 ◽  
Vol 35 (1) ◽  
pp. 7-30 ◽  
Author(s):  
D. M. Cox
Keyword(s):  
Dike Swarm ◽  
Wyoming Province ◽  
Rifted Margin

PETROGENESIS, AGE, AND CORRELATION OF THE KAZAN DIKE SWARM, NUNAVUT, CANADA: IMPLICATIONS FOR AN ABORTED RIFT ORIGIN FOR THE SNOWBIRD TECTONIC ZONE

2016 ◽  
Author(s):  
Lisa J. Grohn ◽  
◽  
Sean P. Regan ◽  
Michael L. Williams ◽  
Larissa De Santana Do Nascimento ◽  
...  
Keyword(s):  
Tectonic Zone ◽  
Dike Swarm

ROCKY MOUNTAINS RIDE HIGH ON ANCIENT RIFTED MARGIN

2019 ◽  
Author(s):  
Kendra E. Murray ◽  
◽  
Marin K. Clark ◽  
Marin K. Clark ◽  
Nathan A. Niemi ◽  
...  
Keyword(s):  
Rocky Mountains ◽  
Rifted Margin

scholarly journals Melt volume at Atlantic volcanic rifted margins controlled by depth-dependent extension and mantle temperature

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gang Lu ◽  
Ritske S. Huismans
Keyword(s):  
Numerical Models ◽  
Potential Temperature ◽  
Analytical Prediction ◽  
Natural Systems ◽  
Passive Margins ◽  
Margin Width ◽  
Rifted Margins ◽  
Mantle Potential Temperature ◽  
Mantle Temperature ◽  
Rifted Margin

AbstractBreakup volcanism along rifted passive margins is highly variable in time and space. The factors controlling magmatic activity during continental rifting and breakup are not resolved and controversial. Here we use numerical models to investigate melt generation at rifted margins with contrasting rifting styles corresponding to those observed in natural systems. Our results demonstrate a surprising correlation of enhanced magmatism with margin width. This relationship is explained by depth-dependent extension, during which the lithospheric mantle ruptures earlier than the crust, and is confirmed by a semi-analytical prediction of melt volume over margin width. The results presented here show that the effect of increased mantle temperature at wide volcanic margins is likely over-estimated, and demonstrate that the large volumes of magmatism at volcanic rifted margin can be explained by depth-dependent extension and very moderate excess mantle potential temperature in the order of 50–80 °C, significantly smaller than previously suggested.

Pre-existing basement structure and its influence on continental rifting and fracture zone development along Australia’s southern rifted margin

2013 ◽  
Vol 170 (2) ◽  
pp. 365-377 ◽  
Author(s):  
G. M. Gibson ◽  
J. M. Totterdell ◽  
L. T. White ◽  
C. H. Mitchell ◽  
A. R. Stacey ◽  
...  
Keyword(s):  
Fracture Zone ◽  
Continental Rifting ◽  
Basement Structure ◽  
Zone Development ◽  
Rifted Margin

Lithospheric roots beneath western Laurentia: the geochemical signal in mantle garnets

2003 ◽  
Vol 40 (8) ◽  
pp. 1027-1051 ◽  
Author(s):  
D Canil ◽  
D J Schulze ◽  
D Hall ◽  
B C Hearn Jr. ◽  
S M Milliken
Keyword(s):  
Rare Earth ◽  
North America ◽  
Trace Element ◽  
Earth Element ◽  
Geochemical Data ◽  
Trace Element Data ◽  
Mantle Lithosphere ◽  
Western North America ◽  
Wyoming Province ◽  
Thick Mantle

This study presents major and trace element data for 243 mantle garnet xenocrysts from six kimberlites in parts of western North America. The geochemical data for the garnet xenocrysts are used to infer the composition, thickness, and tectonothermal affinity of the mantle lithosphere beneath western Laurentia at the time of kimberlite eruption. The garnets record temperatures between 800 and 1450°C using Ni-in-garnet thermometry and represent mainly lherzolitic mantle lithosphere sampled over an interval from about 110–260 km depth. Garnets with sinuous rare-earth element patterns, high Sr, and high Sc/V occur mainly at shallow depths and occur almost exclusively in kimberlites interpreted to have sampled Archean mantle lithosphere beneath the Wyoming Province in Laurentia, and are notably absent in garnets from kimberlites erupting through the Proterozoic Yavapai Mazatzal and Trans-Hudson provinces. The similarities in depths of equilibration, but differing geochemical patterns in garnets from the Cross kimberlite (southeastern British Columbia) compared to kimberlites in the Wyoming Province argue for post-Archean replacement and (or) modification of mantle beneath the Archean Hearne Province. Convective removal of mantle lithosphere beneath the Archean Hearne Province in a "tectonic vise" during the Proterozoic terminal collisions that formed Laurentia either did not occur, or was followed by replacement of thick mantle lithosphere that was sampled by kimberlite in the Triassic, and is still observed there seismically today.

Geologic Map of the Park Reservoir Quadrangle, Sheridan County, Wyoming

2020 ◽  
Vol 57 (4) ◽  
pp. 375-388
Author(s):  
Ryan Bessen ◽  
Jennifer Gifford ◽  
Zack Ledbetter ◽  
Sean McGuire ◽  
Kyle True ◽  
...  
Keyword(s):  
Structural Features ◽  
Geologic Mapping ◽  
Rock Types ◽  
Basement Rocks ◽  
Geologic Maps ◽  
Geologic Map ◽  
Tear Fault ◽  
Mapping Techniques ◽  
Wyoming Province ◽  
Bighorn Mountains

This project involved the construction of a detailed geologic map of the Park Reservoir, Wyoming 7.5-Minute Quadrangle (Scale 1:24,000). The Quadrangle occurs entirely in the Bighorn National Forest, which is a popular recreation site for thousands of people each year. This research advances the scientific understanding of the geology of the Bighorn Mountains and the Archean geology of the Wyoming Province. Traditional geologic mapping techniques were used in concert with isotopic age determinations. Our goal was to further subdivide the various phases of the 2.8–3.0 Ga Archean rocks based on their rock types, age, and structural features. This research supports the broader efforts of the Wyoming State Geological Survey to complete 1:24,000 scale geologic maps of the state. The northern part of the Bighorn Mountains is composed of the Bighorn batholith, a composite complex of intrusive bodies that were emplaced between 2.96–2.87 Ga. Our mapping of the Park Reservoir Quadrangle has revealed the presence of five different Archean quartzofeldspathic units, two sets of amphibolite and diabase dikes, a small occurrence of the Cambrian Flathead Sandstone, two Quaternary tills, and Quaternary alluvium. The Archean rock units range in age from ca. 2.96–2.75 Ga, the oldest of which are the most ancient rocks yet reported in the Bighorn batholith. All the Archean rocks have subtle but apparent planar fabric elements, which are variable in orientation and are interpreted to represent magmatic flow during emplacement. The Granite Ridge tear fault, which is the northern boundary of the Piney Creek thrust block, is mapped into the Archean core as a mylonite zone. This relationship indicates that the bounding faults of the Piney Creek thrust block were controlled by weak zones within the Precambrian basement rocks.

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