TY - JOUR
T1 - Petrogenesis of mesozoic, peraluminous granites in the Lamoille canyon area, Ruby mountains, Nevada, USA
AU - Lee, Sang Yun
AU - Barnes, Calvin G.
AU - Snoke, Arthur W.
AU - Howard, Keith A.
AU - Frost, Carol D.
N1 - Funding Information:
We thank M. Jeon, M. Batum, and A. Strike for their assistance in the field and for generously sharing their ideas and data, and M. Barnes, J. Browning, and C. Beville for assistance in the laboratory. Additional thanks are due to M. Barton, Y. JanousÏ ek, and R. Evart for thorough, insightful reviews. This research was supported by NSF grant EAR-9627814 to C.G.B. and EAR-9627958 to A.W.S. Neutron activation analyses were obtained through the DOE Reactor Sharing Program at Oregon State University.
PY - 2003/4
Y1 - 2003/4
N2 - Two groups of closely associated, peraluminous, two-mica granitic gneiss were identified in the area. The older, sparsely distributed unit is equigranular (EG) with initial εNd ∼ -8·8 and initial 87Sr/86Sr ∼0·7098. Its age is uncertain. The younger unit is Late Cretaceous (∼80 Ma), pegmatitic, and sillimanite-bearing (KPG), with εNd from -15·8 to -17·3 and initial 87Sr/86Sr from 0·7157 to 0·7198. The concentrations of Fe, Mg, Na, Ca, Sr, V, Zr, Zn and Hf are higher, and K, Rb and Th are lower in the EG. Major- and trace-element models indicate that the KPG was derived by muscovite dehydration melting (<35 km depth) of Neoproterozoic metapelitic rocks that are widespread in the eastern Great Basin. The models are broadly consistent with anatexis of crust tectonically thickened during the Sevier orogeny; no mantle mass or heat contribution was necessary. As such, this unit represents one crustal end-member of regional Late Cretaceous peraluminous granites. The EG was produced by biotite dehydration melting at greater depths, with garnet stable in the residue. The source of the EG was probably Paleoproterozoic metagraywacke. Because EG magmatism probably pre-dated Late Cretaceous crustal thickening, it required heat input from the mantle or from mantle-derived magma.
AB - Two groups of closely associated, peraluminous, two-mica granitic gneiss were identified in the area. The older, sparsely distributed unit is equigranular (EG) with initial εNd ∼ -8·8 and initial 87Sr/86Sr ∼0·7098. Its age is uncertain. The younger unit is Late Cretaceous (∼80 Ma), pegmatitic, and sillimanite-bearing (KPG), with εNd from -15·8 to -17·3 and initial 87Sr/86Sr from 0·7157 to 0·7198. The concentrations of Fe, Mg, Na, Ca, Sr, V, Zr, Zn and Hf are higher, and K, Rb and Th are lower in the EG. Major- and trace-element models indicate that the KPG was derived by muscovite dehydration melting (<35 km depth) of Neoproterozoic metapelitic rocks that are widespread in the eastern Great Basin. The models are broadly consistent with anatexis of crust tectonically thickened during the Sevier orogeny; no mantle mass or heat contribution was necessary. As such, this unit represents one crustal end-member of regional Late Cretaceous peraluminous granites. The EG was produced by biotite dehydration melting at greater depths, with garnet stable in the residue. The source of the EG was probably Paleoproterozoic metagraywacke. Because EG magmatism probably pre-dated Late Cretaceous crustal thickening, it required heat input from the mantle or from mantle-derived magma.
KW - Crustal melting
KW - Late Cretaceous
KW - Leucogranite
KW - Peraluminous
KW - Sevier orogeny
UR - http://www.scopus.com/inward/record.url?scp=0037657745&partnerID=8YFLogxK
U2 - 10.1093/petrology/44.4.713
DO - 10.1093/petrology/44.4.713
M3 - Article
AN - SCOPUS:0037657745
SN - 0022-3530
VL - 44
SP - 713
EP - 732
JO - Journal of Petrology
JF - Journal of Petrology
IS - 4
ER -