Precambrian history of the eastern Ferris Mountains and Bear Mountain, south-central Wyoming Province

2006 ◽  
Vol 43 (10) ◽  
pp. 1467-1487 ◽  
Author(s):  
Nancy E Bowers ◽  
Kevin R Chamberlain
Keyword(s):  
Shear Zone ◽  
Late Stage ◽  
Mountain Area ◽  
Grade Metamorphism ◽  
Wyoming Craton ◽  
South Central ◽  
Archean Rock ◽  
Basement Rocks ◽  
History Of ◽  
Wyoming Province

The eastern Ferris Mountains and Bear Mountain area of south-central Wyoming contain a complex assemblage of Archean and Proterozoic rock units, including a metasedimentary and metavolcanic supracrustal sequence named the Spanish Mine metamorphic suite, three granitic plutons (Turkey Creek, Ferris Mountains, Bear Mountain), and at least three sets of mafic dikes. The Spanish Mine metamorphic suite was deposited, intruded by mafic sills and (or) dikes, and underwent amphibolite-grade metamorphism and folding just prior to, or synkinematic with, the intrusion of the Turkey Creek metaplutonic suite, U–Pb dated at 2733.5 ± 2 Ma. A second set of mafic dikes intruded the Turkey Creek metaplutonic suite prior to mylonitic shearing and late-stage folding along the Miners Canyon shear zone. These events were followed by intrusion of the Ferris Mountains plutonic suite at ~2717 Ma. The emplacement of the yet undated granite of Bear Mountain records the last phase of Neoarchean magmatism. The timing of magmatism and deformation support a model that the Ferris Mountains basement rocks formed in an arc terrane distinct from the older Wyoming craton and were accreted to the province in the Neoarchean. Intrusion of a third mafic dike set is dated at 2113 ± 15 Ma and may date the silicified, epidote-rich zones that crosscut all of the Archean rock units. Lead isotopic compositions of galena within the Spanish Mine metamorphic suite indicate additional Proterozoic activity and mineralization.

The age of the Lac-Saint-Jean Anorthosite Complex and associated mafic rocks, Grenville Province, Canada

1992 ◽  
Vol 29 (7) ◽  
pp. 1412-1423 ◽  
Author(s):  
Michael D. Higgins ◽  
Otto van Breemen
Keyword(s):  
Shear Zone ◽  
Shear Zones ◽  
Strike Slip ◽  
Short History ◽  
Southwestern Part ◽  
Grenville Province ◽  
South Central ◽  
History Of ◽  
Emplacement Mechanism ◽  
Anorthosite Complex

U–Pb analyses of zircon and baddeleyite from the south-central and southeastern parts of the Lac-Saint-Jean Anorthosite Complex (LSJA) give an igneous crystallization age of 1157 ± 3 Ma. Parts of the anorthosite were deformed in the solid state and subsequently intruded by a diorite megadyke, which also gives a crystallization age of 1157 ± 3 Ma, indicating that crystallization and deformation of the anorthosite were essentially synchronous. The diorite megadyke was intruded into a north-northeast-trending shear zone and deformed by sinistral strike-slip movements. Emplacement was followed by intrusion of a subparallel leucotroctolite megadyke that again gives the same crystallization age and hence dates movement of the shear zone at 1157 ± 3 Ma. This short history of crystallization and synchronous deformation rules out slow diapiric rise as the emplacement mechanism for the anorthosite. Instead, anorthosite parental magmas probably rose up offsets in subvertical strike-slip shear zones to their present level.In the southwestern part of the LSJA an age of 1142 ± 3 Ma is interpreted to represent igneous crystallization. Contemporary thermal metamorphic effects recorded in the southeastern sector by growth of new zircon in granophyric segregations and zircon coronas on baddeleyite suggest this event was more widespread at slightly deeper levels. Evidence has not been found for a separate Grenville regional metamorphism.The emplacement into the LSJA at 1076 ± 3 Ma of two small leucogabbro intrusions was part of a widespread magmatic event similar to the main event at 1157–1142 Ma.

Tectonic and thermal history of the Anialik River area, northwestern Slave Province, Canada

1999 ◽  
Vol 36 (7) ◽  
pp. 1207-1226 ◽  
Author(s):  
C Relf ◽  
H A Sandeman ◽  
M E Villeneuve
Keyword(s):  
Shear Zone ◽  
Continental Crust ◽  
Greenstone Belt ◽  
Volcanic Rocks ◽  
Crustal Thickening ◽  
South Central ◽  
Slave Province ◽  
History Of ◽  
Arc Setting ◽  
Felsic Volcanic

The Anialik River area in the northwestern Slave Province comprises two geological domains of different age and origin that were tectonically juxtaposed at ca. 2650 Ma. The older domain, the Kangguyak gneiss belt, comprises ca. 3300-2700 Ma orthogneisses and paragneisses, interpreted as the remnants of a Mesoarchean continental margin. The younger domain, the Anialik River greenstone belt, consists of ca. 2680 Ma mafic to felsic volcanic rocks interpreted to have formed in an ensimatic island-arc setting. Structural and geochronological evidence suggest collision of the two domains began around 2650 Ma in a transpressive regime that involved oblique (sinistral) subduction of the greenstone belt beneath the Kangguyak domain along the Tokhokatak shear zone. Displacement continued until at least ca. 2600 Ma, when late, two-mica granites intruded along and were deformed in the shear zone. Following ca. 2600 Ma, rocks in both domains and along the fault cooled rapidly to about 350°C. Strongly overprinted muscovite spectra and the young ages for biotite throughout the region imply that a thermal event reset all biotites (but not muscovite) at ca. 2000-1900 Ma, possibly associated with crustal thickening associated with Wopmay (Calderian) orogenesis. The tectonic history of the Anialik River area is significantly different from that documented in the south-central part of the Slave Province, suggesting the Kangguyak domain is a distinct fragment of continental crust that accreted independently from continental crust in the southern Slave Province.

THE SODA CREEK FISH CREEK SHEAR ZONE: USING MULTIPLE GEOCHRONOLOGIC METHODS TO UNRAVEL THE PROTEROZOIC STRUCTURAL HISTORY OF POLYPHASE DEFORMATION IN HIGHLY DEFORMED ROCKS

2016 ◽  
Author(s):  
Bart T. Cubrich ◽  
◽  
Kevin R. Chamberlain ◽  
Ernest Duebendorfer ◽  
Michael L. Williams ◽  
...  
Keyword(s):  
Shear Zone ◽  
Polyphase Deformation ◽  
Structural History ◽  
History Of

REVIEWING AND REVISING THE PROTEROZOIC HISTORY OF THE FIVE POINTS SHEAR ZONE: A MULTIPLY DEFORMED PALEOPROTEROZOIC SHEAR THAT FORMED PRIOR TO 1.67 GA

2018 ◽  
Author(s):  
Bart T. Cubrich ◽  
◽  
Kevin R. Chamberlain ◽  
Ernest M. Duebendorfer ◽  
Matt Cochrane
Keyword(s):  
Shear Zone ◽  
History Of

ΔD VALUES OF SHEAR ZONE MICAS FROM LHAGOI KANGRI IN SOUTH-CENTRAL TIBET SUGGEST A HIGH HIMALAYA BY THE MID-MIOCENE

2019 ◽  
Author(s):  
Anthony J. Krupa ◽  
◽  
Jay Quade ◽  
Paul Kapp
Keyword(s):  
Shear Zone ◽  
South Central ◽  
Central Tibet

EXPLORING THE GEOLOGIC HISTORY OF SOUTH-CENTRAL PENNSYLVANIA FROM GOVERNOR DICK TOWER

2020 ◽  
Author(s):  
Stephen G. Shank ◽  
◽  
Stuart Reese
Keyword(s):  
Geologic History ◽  
South Central ◽  
Central Pennsylvania ◽  
History Of
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