FLARE-UP WITHOUT A CAUSE: THE BEAR VALLEY INTRUSIVE SUITE, SIERRA NEVADA, CALIFORNIA

2019 ◽  
Author(s):  
Benjamin Z. Klein ◽  
◽  
Oliver Jagoutz ◽  
Jahandar Ramezani
Keyword(s):  
Sierra Nevada ◽  
Intrusive Suite

SHIFT FROM SOURCE TO SYSTEM CONTROL ON PLUTON COMPOSITIONS RECORDED IN THE MIGRATED JACK MAIN CANYON INTRUSIVE SUITE IN THE CENTRAL SIERRA NEVADA, CA

2019 ◽  
Author(s):  
Cullen L. Scheland ◽  
◽  
Vali Memeti ◽  
Vali Memeti ◽  
Alejandra Angulo ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
System Control ◽  
Intrusive Suite

PETROLOGY OF MAGMATIC ENCLAVES AND MAFIC DIKES IN THE JACK MAIN CANYON INTRUSIVE SUITE, CENTRAL SIERRA NEVADA

2019 ◽  
Author(s):  
Alejandra Angulo ◽  
◽  
Cullen L. Scheland ◽  
Vali Memeti
Keyword(s):  
Sierra Nevada ◽  
Magmatic Enclaves ◽  
Intrusive Suite

Multistage emplacement of the McDoogle pluton, an early phase of the John Muir intrusive suite, Sierra Nevada, California, by magmatic crack-seal growth

2014 ◽  
Vol 126 (11-12) ◽  
pp. 1569-1579 ◽  
Author(s):  
Michael A. Stearns ◽  
John M. Bartley
Keyword(s):  
Sierra Nevada ◽  
Early Phase ◽  
John Muir ◽  
Intrusive Suite

Isotopic variation in the Tuolumne Intrusive Suite, central Sierra Nevada, California

1986 ◽  
Vol 94 (2) ◽  
pp. 205-220 ◽  
Author(s):  
R. W. Kistler ◽  
B. W. Chappell ◽  
D. L. Peck ◽  
P. C. Bateman
Keyword(s):  
Sierra Nevada ◽  
Isotopic Variation ◽  
Tuolumne Intrusive Suite ◽  
Intrusive Suite

scholarly journals Long-term geochemical variability of the Late Cretaceous Tuolumne Intrusive Suite, central Sierra Nevada, California

2008 ◽  
Vol 304 (1) ◽  
pp. 183-201 ◽  
Author(s):  
Walt Gray ◽  
Allen F. Glazner ◽  
Drew S. Coleman ◽  
John M. Bartley
Keyword(s):  
Sierra Nevada ◽  
Late Cretaceous ◽  
Tuolumne Intrusive Suite ◽  
Intrusive Suite

Interpreting magmatic processes from accessory phases: titanite—a small-scale recorder of large-scale processes

2000 ◽  
Vol 91 (1-2) ◽  
pp. 257-267 ◽  
Author(s):  
Philip Piccoli ◽  
Philip Candela ◽  
Mark Rivers
Keyword(s):  
Sierra Nevada ◽  
Large Scale ◽  
Functional Dependence ◽  
Trace Element Analysis ◽  
Quartz Diorite ◽  
Small Scale ◽  
Element Analysis ◽  
General Behaviour ◽  
Rock Composition ◽  
Intrusive Suite

In this study we examined variations in ore and other trace-metal concentrations in titanite, a ubiquitous product of magmatic (and subsequent sub-solidus) crystallisation in oxidised silicic magmas. Accessory titanite occurs in the Tuolumne Intrusive Suite (TIS), Sierra Nevada Batholith, as euhedral to anhedral, poikilitic, or interstitial grains. Zoned crystals of titanite were analysed by electron microprobe and synchrotron X-ray fluorescence for major and trace elements. Backscatter electron images reveal zoning, with bright areas correlating positively with total REE concentrations. REE concentrations generally decrease toward the edge of titanite crystals; however, some crystals are reversely zoned, and others exhibit oscillatory or patchy zoning; some grains contain discrete anhedral cores. Most elements in magmatic titanite decrease in concentration towards crystal rims, independent of host rock composition.At least one major reduction event in the magma chamber(s) transiently stabilised ilmenite, now present only as inclusions in titanite, and resulted in a reduction in the REE concentration in titanite. We suggest the hypothesis that the reduction in the REE concentration in these zones is due to the diminished activity of the (REE)Fe3+Ca−1Ti−1exchange component; however, the scatter in the data, together with the operation of other exchange vectors for Fe and Al, did not allow us to test this hypothesis herein. Secondary (i.e. sub solidus, hydrothermal) titanite can be recognised on the basis of its chemistry, sometimes by its anhedral form, and by its position as an alteration rim around primary magmatic phases; however, secondary titanite growth on primary titanite crystals may be harder to discern. Secondary titanite rims on magnetite contain higher Cr, Zr and Mo, and lower REE, relative to magmatic titanite. U/Th ratios increase toward the rim of most titanite grains; however, Th decreases in concentration from core to rim. This is due, most likely, to complications resulting from the coupled substitutions necessary for replacement of Ca by tetravalent Th; factors of this sort are commonly overlooked in trace element analysis.The analysed titanites are from rocks of the normally zoned TIS which ranges in87Sr/86Sri, from 0·7059 (tonalite and quartz-diorite) to 0·7066 (granite). Many element ratios in the titanites exhibit little to no functional dependence on87Sr/86Sri. However, log Mo/W increases with increasing87Sr/86Sri, of the host unit from the equigranular quartz-diorite and tonalite, to the interior granodiorites, possibly reflecting the greater crustal contribution to the interior, more felsic units. Neither Mo nor W increase significantly from core to rim in titanite. If these trends are indicative of the general behaviour of these elements duringin-situfractionation, then these data suggest that Mo and W are not strongly incompatible, and indeed may behave compatibly, in some titaniteand magnetite-bearing granodioritic magmas.

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