scholarly journals Major- and trace-element geochemistry; lead, strontium, and neodymium isotopic compositions; and petrography of late Cenozoic basaltic rocks from west central Colorado

2001 ◽  
Author(s):  
D.M. Unruh ◽  
J.R. Budahn ◽  
D.F. Siems ◽  
F.M. Byers
Keyword(s):  
Trace Element ◽  
Trace Element Geochemistry ◽  
Late Cenozoic ◽  
Element Geochemistry ◽  
Basaltic Rocks ◽  
Isotopic Compositions ◽  
West Central

scholarly journals Supplemental Material: Postcaldera intrusive magmatism at the Platoro caldera complex, Southern Rocky Mountain volcanic field, Colorado, USA

2021 ◽  
Author(s):  
A.K. Gilmer ◽  
et al.
Keyword(s):  
Trace Element ◽  
Rocky Mountain ◽  
Volcanic Field ◽  
Trace Element Geochemistry ◽  
Zircon Geochronology ◽  
Element Geochemistry ◽  
Isotopic Compositions ◽  
Southern Rocky Mountain

<div>Table S1: Whole-rock compositions of analyzed samples. Table S2: Major and trace element geochemistry of feldspar. Table S3: Major and trace element geochemistry of pyroxene. Table S4: Major and trace element geochemistry of biotite. Table S5: Major and trace element geochemistry of amphibole. Table S6: Zircon geochronology and trace element geochemistry. Table S7: Lutetium and hafnium isotopic compositions of zircon. Table S8: Amphibole-plagioclase thermometry. Table S9: Sample locations and lithologies.<br></div>

scholarly journals Trace-element and Sr and Nd isotopic geochemistry of Cretaceous bentonites in Wyoming and South Dakota tracks magmatic processes during eastward migration of Farallon arc plutons

2020 ◽  
Author(s):  
Jeffrey S. Hannon ◽  
Craig Dietsch ◽  
Warren D. Huff
Keyword(s):  
South Dakota ◽  
Trace Element ◽  
Temporal Trends ◽  
Western Montana ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
Data Set ◽  
Isotopic Compositions ◽  
Clay Deposits ◽  
Magmatic Processes

Bentonite beds, which are clay deposits produced by the submarine alteration of volcanic tephra, preserve millions of years of volcanic products linked to magmatic systems for which records are otherwise lost through erosion and alteration. Cretaceous strata from the Bighorn Basin, Wyoming, and southwestern South Dakota contain bentonites that originated from arc magmatism produced by subduction of the Farallon plate. We analyzed the bulk major- and trace-element geochemistry, and the 87Sr/86Sr (n = 87) and 143Nd/144Nd (n = 26) isotopic compositions of individual bentonite beds from these areas spanning 40 m.y. of volcanism to recover signals of magmatic processes and to attempt to trace bentonite geochemical and isotopic signatures to contemporaneous Cordilleran plutonic rocks. Using multiple immobile elements (e.g., Zr, TiO2, Nb, Ta, and rare earth elements), distinct temporal trends show variations in the effects of mineral fractionation and changes in crustal thickness. Bentonite Sr and Nd isotopic compositions allow ash beds to be correlated with specific batholithic complexes in Idaho and western Montana. With this data set, we observed the following: (1) The volcanic arc migrated across the 0.706 isopleth between 115 and 105 Ma; (2) between 105 and 95 Ma, magmatism stalled in central Idaho and was supported through significant MASH (mixing-assimilation-storage-homogenization) processing; (3) by 85 Ma, a shallowing subduction angle resulted in the eastward migration of the volcanic front into western Montana while volcanism in Idaho diminished; and (4) around 75 Ma, evidence of Idaho volcanism is lost. Montana plutonism continued with significant assimilation of radiogenic basement and regional centers of local magma emplacement (i.e., Pioneer batholith).

REGIONAL TRACE ELEMENT GEOCHEMISTRY OF ZIRCONS IN THE JURASSIC VOLCANIC ARC OF THE SOUTHWEST U.S

2016 ◽  
Author(s):  
Jennifer A. Laughlin ◽  
◽  
Joseph L. Wooden ◽  
A.P. Barth ◽  
John T. Shukle ◽  
...  
Keyword(s):  
Trace Element ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
Volcanic Arc
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