Publication Date
Fall 2011
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Geology
Advisor
Jonathan Miller
Keywords
Aztec Wash pluton, stoping
Subject Areas
Geology; Geochemistry
Abstract
The Miocene Aztec Wash pluton, Eldorado Mountains (NV), has been tilted by regional extension and thus provides a vertical cross-section showing 5 km structural depth. Previous work shows that the Aztec Wash pluton was constructed by vertical accumulation of mafic sheets intruded into granite magma with widespread hybridization. Precambrian orthogneiss and Cretaceous granite host rock xenoliths (1 cm to >20 m long dimension) occur at all structural levels but are heterogeneously distributed (locally varying from 0 to 50% of areal exposure). Their origin and relation to the Aztec Wash pluton are poorly known. Mapping at 1:6000 of a xenolith-rich area has shown that 1) xenolith size and integrity of contacts with surrounding plutonic rock are highly variable; 2) sub-solidus fabrics in xenoliths show no preferred orientation compared to host rocks in the pluton roof; 3) xenoliths display evidence of mechanical disaggregation, but geochemistry suggests minimal assimilation; and 4) draping of sheets over xenoliths indicate they are stratabound within the mafic sheet sequences. These observations, together with documented vertical growth of the pluton and the distribution of host rock xenoliths, suggest episodic detachment and stoping of surrounding host rocks (possibly during eruption) to form xenoliths.
Recommended Citation
Smith, Jamie Nicole, "Incorporation of Host Rock Blocks During the Growth of the Aztec Wash Pluton, Eldorado Mountains, Nevada" (2011). Master's Theses. 4113.
DOI: https://doi.org/10.31979/etd.zdas-tm4s
https://scholarworks.sjsu.edu/etd_theses/4113
