Robert Ayuso
Robert Ayuso is a Research Geologist with the USGS Geology, Energy & Minerals (GEM) Science Center in Reston, VA.
Science and Products
Filter Total Items: 82
Comparative geochronology in the reversely zoned plutons of the Bottle Lake Complex, Maine: U-Pb on zircons and Rb-Sr on whole rocks Comparative geochronology in the reversely zoned plutons of the Bottle Lake Complex, Maine: U-Pb on zircons and Rb-Sr on whole rocks
The Bottle Lake Complex is a composite granitic batholith emplaced into Cambrian to Lower Devonian metasedimentary rocks. Both plutons (Whitney Cove and Passadumkeag River) are very coarse grained hornblende and biotite-bearing granites showing petrographic and geochemical reverse zonation. Two linear whole rock Rb/Sr isochrons on xenolith-free Whitney Cove and Passadumkeag River samples...
Authors
R. A. Ayuso, Joseph G. Arth, A.K. Sinha, J. Carlson, D. R. Wones
Manganese-rich red tourmaline from the Fowler talc belt, New York. Manganese-rich red tourmaline from the Fowler talc belt, New York.
Red uvite containing up to 4.34 wt.% MnO is found in the Arnold talc mine near Fowler, New York, USA. Microprobe analyses give a composition of 51% uvite in the uvite-dravite series. Associated minerals in this manganiferous metamorphic assemblage (possibly an evaporite) are manganese-rich tremolite (hexagonite) braunite and quartz.-R.A.G.
Authors
R. A. Ayuso, C. Erwin Brown
Quartz-molybdenite veins in the Priestly Lake granodiorite, north-central Maine Quartz-molybdenite veins in the Priestly Lake granodiorite, north-central Maine
Quartz-molybdenite veins up to 15 cm in width occur in fine to medium-grained porphyritic biotite-hornblende granodiorite at Priestly Lake north-central Maine. An area of about 150 m x 150 m contains quartz-molybdenite veins; a larger area is characterized by barren quartz veins. Quartz-molybdenite veins are concentrated within the most felsic variants of the intrusion as suggested by...
Authors
Robert A. Ayuso, Stephen G. Shank
Science and Products
Filter Total Items: 82
Comparative geochronology in the reversely zoned plutons of the Bottle Lake Complex, Maine: U-Pb on zircons and Rb-Sr on whole rocks Comparative geochronology in the reversely zoned plutons of the Bottle Lake Complex, Maine: U-Pb on zircons and Rb-Sr on whole rocks
The Bottle Lake Complex is a composite granitic batholith emplaced into Cambrian to Lower Devonian metasedimentary rocks. Both plutons (Whitney Cove and Passadumkeag River) are very coarse grained hornblende and biotite-bearing granites showing petrographic and geochemical reverse zonation. Two linear whole rock Rb/Sr isochrons on xenolith-free Whitney Cove and Passadumkeag River samples...
Authors
R. A. Ayuso, Joseph G. Arth, A.K. Sinha, J. Carlson, D. R. Wones
Manganese-rich red tourmaline from the Fowler talc belt, New York. Manganese-rich red tourmaline from the Fowler talc belt, New York.
Red uvite containing up to 4.34 wt.% MnO is found in the Arnold talc mine near Fowler, New York, USA. Microprobe analyses give a composition of 51% uvite in the uvite-dravite series. Associated minerals in this manganiferous metamorphic assemblage (possibly an evaporite) are manganese-rich tremolite (hexagonite) braunite and quartz.-R.A.G.
Authors
R. A. Ayuso, C. Erwin Brown
Quartz-molybdenite veins in the Priestly Lake granodiorite, north-central Maine Quartz-molybdenite veins in the Priestly Lake granodiorite, north-central Maine
Quartz-molybdenite veins up to 15 cm in width occur in fine to medium-grained porphyritic biotite-hornblende granodiorite at Priestly Lake north-central Maine. An area of about 150 m x 150 m contains quartz-molybdenite veins; a larger area is characterized by barren quartz veins. Quartz-molybdenite veins are concentrated within the most felsic variants of the intrusion as suggested by...
Authors
Robert A. Ayuso, Stephen G. Shank