Date File Created	Name of Creator										
2/8/2011	Josh Rosera - UNC										
GeoRef Data	2010-080681										
DN	GeoRef										
TI	"U-Pb geochronology of Proterozoic granites in the Sawatch Range, central Colorado, U.S.A."										
AU	"Jones, James V III; Rogers, Steven A; Connelly, James N"										
AF	"Department of Earth Sciences, University of Arkansas at Little Rock, Little Rock, Arkansas 72204, U.S.A."										
SO	Contributions to Geology 45.1 (2010): 1-22										
IS	2220950										
CD	WUGGAO										
AB	"We report new U-Pb zircon ages for four previously undated Proterozoic granitoid intrusions exposed in the southern Sawatch Range, central Colorado. Coarse-grained to K-feldspar megacrystic granite (Henry Mountain granite) exposed along Taylor Canyon 20 km north of Gunnison, Colorado, crystallized at 1697 + or - 7 Ma. It cuts across high-temperature deformational fabrics in metavolcanic and metasedimentary country rocks, thus bracketing at least one Paleoproterozoic tectonic event locally. This granite also contains a well-developed northeast-striking, subvertical foliation that postdates emplacement. The three other intrusions all yielded Mesoproterozoic ages. The Monarch Pass pluton, comprising coarse- to medium-grained granodiorite exposed 50 km east of Gunnison, crystallized at 1447 + or - 9 Ma. It cuts across well-developed fabrics in metavolcanic host rocks and contains a widespread biotite foliation. Coarse-grained to K-feldspar megacrystic granite (Horsethief granite) exposed 5-10 km northwest of Taylor Park Reservoir was emplaced at 1437 + or - 5 Ma, and it is locally deformed. Fine-grained, muscovite-biotite granite (Taylor River granite) that cuts across the southwestern part of the Henry Mountain Pluton crystallized at 1428 + or - 23 Ma. A subvertical, northeast-striking biotite foliation cuts across the contact between these two intrusions, suggesting that northwest-directed subhorizontal shortening occurred locally during the Mesoproterozoic. These ages provide new opportunities to constrain the age of tectonism in central Colorado and to further understand the Proterozoic tectonic evolution of southern Laurentia."										
LA	English										
FE	"References: 82, illus. incl. geol. sketch map"										
PY	2010										
PT	Serial; Analytic										
CP	United States (USA)										
CL	"05A Igneous and metamorphic petrology, 03 Geochronology"										
CY	"GeoRef, Copyright 2008, American Geological Institute. Abstract, copyright, University of Wyoming | Reference includes data from GeoScienceWorld, Alexandria, VA, United States"										
AN	2010-080681										
Sample Data											
Item	LatDD	LongDD	Loc_prec	Age	Max_age	Min_age	Rock_Type	Rock_Class	Location_Name	Material	State
Units	dd	dd		ma	ma	ma					
Method	1	1		2	2	2					
Sample Name											
J02-SC2	38.731536	-106.742945	0.0001	1697	1704	1690	Plutonic	Granite	Sawatch Range	Zircon	Colorado
J02-SC3	38.897178	-106.62912	0.0001	1437	1442	1432	Plutonic	Granite	Sawatch Range	Zircon	Colorado
J01-M1	38.511216	-106.327742	0.0001	1447	1456	1438	Plutonic	Granodiorite	Sawatch Range	Zircon	Colorado
J02-SC1	38.729196	-106.764377	0.0001	1428	1451	1397	Plutonic	Granite	Sawatch Range	Zircon	Colorado
Method Data											
1	TABLE	2010-080681									
2	U-PBC:ZIRC	472