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
A geochemical isotopic (Nd-Pb) comparison of volcanic rocks erupted during the last 3,550 yrs. B.P. of interplinian activity of Somma-Vesuvius Volcano, southern Italy A geochemical isotopic (Nd-Pb) comparison of volcanic rocks erupted during the last 3,550 yrs. B.P. of interplinian activity of Somma-Vesuvius Volcano, southern Italy
No abstract available.
Authors
Renato Somma, Robert A. Ayuso, B. de Vivo
Radiogenic isotopes and the Eastern Mineral Resources Program of the U.S. Geological Survey Radiogenic isotopes and the Eastern Mineral Resources Program of the U.S. Geological Survey
Radiogenic isotope geology relies on a small group of naturally occurring but unstable elements that naturally produce energy and disintegrate or decay to more stable atoms of different elements. Because this phenomenon occurs at a known rate, is unaffected by most physical and chemical processes, and takes place over periods of time comparable to the age of the Earth, these elements can...
Authors
Robert A. Ayuso
Carolina slate belt gold deposits in Virginia, North Carolina, South Carolina, and Georgia Carolina slate belt gold deposits in Virginia, North Carolina, South Carolina, and Georgia
The Southeastern United States, in particular, the Carolina slate belt of Virginia, North Carolina, South Carolina, and Georgia, has been an important region of mineral production (fig. 1). This region is thought to have major potential for containing large undiscovered deposits of gold and silver, as well as copper, lead, zinc, molybdenum, and tin. Gold production from the major mines...
Authors
Robert A. Ayuso
Geochemical and isotopic (Nd-Pb-Sr-O) variations bearing on the genesis of volcanic rocks from Vesuvius, Italy Geochemical and isotopic (Nd-Pb-Sr-O) variations bearing on the genesis of volcanic rocks from Vesuvius, Italy
Alkaline volcanism produced by Monte Somma-Vesuvius volcano includes explosive plinian and subplinian activity in addition to effusive lava flows. Pumice, scoria, and lava (150 samples) exhibit major- and trace-element gradients as a function of SiO2 (58.9-47.2 wt%) and MgO (0-7.8 wt%); Mg value are ???50. Internally gradational chemical groups or cycles are distinguished by age: (1) 25...
Authors
R. A. Ayuso, B. de Vivo, G. Rolandi, R.R. Seal, A. Paone
The Spruce Head composite pluton: An example of mafic to silicic Salinian magmatism in coastal Maine, northern Appalachians The Spruce Head composite pluton: An example of mafic to silicic Salinian magmatism in coastal Maine, northern Appalachians
No abstract available.
Authors
Robert A. Ayuso, Joseph G. Arth
Pb and O isotopic constraints on the source of granitic rocks from Cape Breton Island, Nova Scotia, Canada Pb and O isotopic constraints on the source of granitic rocks from Cape Breton Island, Nova Scotia, Canada
Pb isotopic compositions of leached feldspars from twenty-three plutons in Cape Breton Island can be divided into two groups: anorthosite, syenite, and granite in the Blair River Complex, which have the least radiogenic compositions on the Island, and granitic rocks from terranes (Aspy, Bras d'Or, and Mira) to the south. Pb isotopic data for the Blair River Complex (206Pb/204Pb = 17.399...
Authors
Robert A. Ayuso, S. M. Barr, Frederick J. Longstaffe
Science and Products
Filter Total Items: 82
A geochemical isotopic (Nd-Pb) comparison of volcanic rocks erupted during the last 3,550 yrs. B.P. of interplinian activity of Somma-Vesuvius Volcano, southern Italy A geochemical isotopic (Nd-Pb) comparison of volcanic rocks erupted during the last 3,550 yrs. B.P. of interplinian activity of Somma-Vesuvius Volcano, southern Italy
No abstract available.
Authors
Renato Somma, Robert A. Ayuso, B. de Vivo
Radiogenic isotopes and the Eastern Mineral Resources Program of the U.S. Geological Survey Radiogenic isotopes and the Eastern Mineral Resources Program of the U.S. Geological Survey
Radiogenic isotope geology relies on a small group of naturally occurring but unstable elements that naturally produce energy and disintegrate or decay to more stable atoms of different elements. Because this phenomenon occurs at a known rate, is unaffected by most physical and chemical processes, and takes place over periods of time comparable to the age of the Earth, these elements can...
Authors
Robert A. Ayuso
Carolina slate belt gold deposits in Virginia, North Carolina, South Carolina, and Georgia Carolina slate belt gold deposits in Virginia, North Carolina, South Carolina, and Georgia
The Southeastern United States, in particular, the Carolina slate belt of Virginia, North Carolina, South Carolina, and Georgia, has been an important region of mineral production (fig. 1). This region is thought to have major potential for containing large undiscovered deposits of gold and silver, as well as copper, lead, zinc, molybdenum, and tin. Gold production from the major mines...
Authors
Robert A. Ayuso
Geochemical and isotopic (Nd-Pb-Sr-O) variations bearing on the genesis of volcanic rocks from Vesuvius, Italy Geochemical and isotopic (Nd-Pb-Sr-O) variations bearing on the genesis of volcanic rocks from Vesuvius, Italy
Alkaline volcanism produced by Monte Somma-Vesuvius volcano includes explosive plinian and subplinian activity in addition to effusive lava flows. Pumice, scoria, and lava (150 samples) exhibit major- and trace-element gradients as a function of SiO2 (58.9-47.2 wt%) and MgO (0-7.8 wt%); Mg value are ???50. Internally gradational chemical groups or cycles are distinguished by age: (1) 25...
Authors
R. A. Ayuso, B. de Vivo, G. Rolandi, R.R. Seal, A. Paone
The Spruce Head composite pluton: An example of mafic to silicic Salinian magmatism in coastal Maine, northern Appalachians The Spruce Head composite pluton: An example of mafic to silicic Salinian magmatism in coastal Maine, northern Appalachians
No abstract available.
Authors
Robert A. Ayuso, Joseph G. Arth
Pb and O isotopic constraints on the source of granitic rocks from Cape Breton Island, Nova Scotia, Canada Pb and O isotopic constraints on the source of granitic rocks from Cape Breton Island, Nova Scotia, Canada
Pb isotopic compositions of leached feldspars from twenty-three plutons in Cape Breton Island can be divided into two groups: anorthosite, syenite, and granite in the Blair River Complex, which have the least radiogenic compositions on the Island, and granitic rocks from terranes (Aspy, Bras d'Or, and Mira) to the south. Pb isotopic data for the Blair River Complex (206Pb/204Pb = 17.399...
Authors
Robert A. Ayuso, S. M. Barr, Frederick J. Longstaffe