U-Pb zircon geochronology of Proterozoic and Cambrian plutons in the Wet Mountains and southern Front Range, Colorado

Bickford, M. E.; Cullers, Robert L.; Shuster, Robert Duncan; Premo, Wayne R.; Schmus, W. R. Van

doi:10.1130/spe235-p49

Cited by 41 publications

(52 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Further, there are numerous places where the younger magmatism took place in an area that had already undergone the older Mesoproterozoic magmatism (e.g., 1440-1470 Ma, then ca. 1365 Ma magmatism in the Wet Mountains, Colorado, Bickford et al, 1989). Additional age data may refine and change these apparent patterns, but several major conclusions, that are unlikely to change with additional data, must be explained by any viable tectonic model.…”

Section: Implications Of Regional (Zircon) Age Distribution and Populmentioning

confidence: 91%

Mesoproterozoic-trans-Laurentian magmatism: A synthesis of continent-wide age distributions, new SIMS U–Pb ages, zircon saturation temperatures, and Hf and Nd isotopic compositions

Bickford

Schmus

Karlstrom

et al. 2015

Precambrian Research

170

View full text Add to dashboard Cite

Section: Implications Of Regional (Zircon) Age Distribution and Populmentioning

confidence: 91%

Mesoproterozoic-trans-Laurentian magmatism: A synthesis of continent-wide age distributions, new SIMS U–Pb ages, zircon saturation temperatures, and Hf and Nd isotopic compositions

Bickford

Schmus

Karlstrom

et al. 2015

Precambrian Research

170

View full text Add to dashboard Cite

“…Tectonism and associated metamorphism in the age range 1560-1620 Ma has been documented in other Paleoproterozoic terranes of the southwestern United States and appears to be associated with large-scale crustal tectonism along pre-existing shear zones thought to be accretionary structures (e.g., Premo and Van Schmus, 1989;Bickford et al, 1989;Shaw et al, 1999;Premo and Fanning, 2000;Duebendorfer and Chamberlain, 2002;Strickland et al, 2004;Duebendorfer et al, 2004). Furthermore, similar isotopic results have been documented in zircons from recrystallized granitic gneisses in northeast Queensland, Australia (Hoskin and Black, 2000), interpreted as the result of high-grade metamorphism during the Jana orogeny between 1550 and 1600 Ma.…”

Section: Ages Of Recrystallization and Metamorphismmentioning

confidence: 94%

Contrasting Proterozoic basement complexes near the truncated margin of Laurentia, northwestern Sonora–Arizona international border region

Nourse¹,

Premo²,

Iriondo³

et al. 2005

The Mojave-Sonora Megashear Hypothesis: Development, Assessment, and Alternatives

View full text Add to dashboard Cite

We utilize new geological mapping, conventional isotope dilution-thermal ionization mass spectrometry (ID-TIMS) and sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon analyses, and whole-rock radiogenic isotope characteristics to distinguish two contrasting Proterozoic basement complexes in the international border region southeast of Yuma, Arizona. Strategically located near the truncated southwest margin of Laurentia, these Proterozoic exposures are separated by a northwest-striking Late Cretaceous batholith. Although both complexes contain strongly deformed Paleoproterozoic granitoids (augen gneisses) intruded into fi ne-grained host rocks, our work demonstrates marked differences in age, host rock composition, and structure between the two areas.The Western Complex reveals a >5-km-thick tilted section of fi nely banded felsic, intermediate, and mafi c orthogneiss interspersed with tabular intrusive bodies of medium-grained leucocratic biotite granite (1696 ± 11 Ma; deepest level), mediumgrained hornblende-biotite granodiorite (1722 ± 12 Ma), and coarse-grained porphyritic biotite granite (1725 ± 19 Ma; shallowest level). Penetrative ductile deformation has converted the granites to augen gneisses and caused isoclinal folding and transposition of primary contacts. Exposed in a belt of northwest-trending folds, these rocks preserve southwest-vergent shear fabric annealed during amphibolite facies Nourse, J.A., Premo, W.R., Iriondo, A., and Stahl, E.R., 2005, Contrasting Proterozoic basement complexes near the truncated margin of Laurentia, northwestern Sonora-Arizona international border region, in Anderson, T.on May 31, 2015 specialpapers.gsapubs.org Downloaded from 124 J.A. Nourse et al. metamorphism, when crystalloblastic textures developed. Deformation and regional metamorphism occurred before emplacement of 1.1 Ga(?) mafi c dikes.Throughout the Eastern Complex, meta-arkose, quartzite, biotite schist, and possible felsic metavolcanic rocks comprise the country rocks of strongly foliated medium-and coarse-grained biotite granite augen gneisses that yield mean 207 Pb/ 206 Pb ages of 1646 ± 10 Ma, 1642 ± 19 Ma, and 1639 ± 15 Ma. Detrital zircons from four samples of host sandstone are isotopically disturbed; nevertheless, the data indicate a restricted provenance (ca. 1665 Ma to 1650 Ma), with two older grains (1697 and 1681 Ma). The pervasively recrystallized Paleoproterozoic map units strike parallel to foliation and are repeated in south-trending folds that are locally refolded about easterly hinges. Southeasterly lineation developed in augen gneiss and host strata becomes penetrative in local domains of L-tectonite. Regional metamorphism associated with this tectonism persisted until ca. 1590 Ma, as recorded by metamorphic growths within some zircon grains. Mesoproterozoic intrusions that crosscut the Paleoproterozoic metasediments and augen gneisses include coarsely porphyritic biotite granite (1432 ± 6 Ma) and diabase dikes (1.1 Ga?). Emplacement of the granite was accompanied by secondary hig...

show abstract

“…Ages of the metamorphic rocks are not well defined, but accumulation and probably initial deformation and metamorphism, of shale and graywacke occurred before 1700 Ma ago (Bickford, 1988;Bickford et al, 1989); no pre-1800 Ma basement has been recognized (Reed et al, 1987). The metamorphic rocks are probably coeval with accretion of the Salida-Gunnison magmatic arc complex, interpreted to be a 1770 to 1730 Ma juvenile island arc terrane (Reed, 1987).…”

Section: Regional Geologic Settingmentioning

confidence: 99%

Petrology and geochemistry of late-stage intrusions of the A-type, mid-Proterozoic Pikes Peak batholith (Central Colorado, USA): implications for petrogenetic models

Smith

Noblett

Wobus

et al. 1999

Precambrian Research

164

View full text Add to dashboard Cite

. (1999). Petrology and geochemistry of late-stage intrusions of the a-type, mid-Proterozoic pikes peak batholith (central Colorado, USA): Implications for petrogenetic models. Precambrian Research,, 271-305. doi:10.1016/ S0301-9268(99) Gabbros and mafic dikes associated with the sodic granitoids have ߳ Nd (1.08 Ga) of −3.0 to +3.5, which are lower than depleted mantle at 1.08 Ga, and their trace element characteristics suggest derivation from mantle sources that were previously affected by subduction-related processes. However, it is difficult to characterize the mantle component in these magmas, because assimilation of crust during magma ascent could also result in their observed geochemical features.The Pikes Peak batholith is composed of at least two petrogenetically different granite types, both of which exhibit geochemical characteristics typical of A-type granites. Models proposed for the petrogenesis of the granitoids imply the existence of mafic rocks at depth and addition of juvenile material to the crust in central Colorado at ~1.1 Ga.3

show abstract

U-Pb zircon geochronology of Proterozoic and Cambrian plutons in the Wet Mountains and southern Front Range, Colorado

Cited by 41 publications

References 0 publications

Mesoproterozoic-trans-Laurentian magmatism: A synthesis of continent-wide age distributions, new SIMS U–Pb ages, zircon saturation temperatures, and Hf and Nd isotopic compositions

Mesoproterozoic-trans-Laurentian magmatism: A synthesis of continent-wide age distributions, new SIMS U–Pb ages, zircon saturation temperatures, and Hf and Nd isotopic compositions

Contrasting Proterozoic basement complexes near the truncated margin of Laurentia, northwestern Sonora–Arizona international border region

Petrology and geochemistry of late-stage intrusions of the A-type, mid-Proterozoic Pikes Peak batholith (Central Colorado, USA): implications for petrogenetic models

Contact Info

Product

Resources

About