Floyd Gray

Publications listing

Interests: 

Applied multi-disciplinary research, outreach, and education training in support of land and resource awareness and informed management decision making in the southwestern U.S.

520-670-5582

Fax 520-670-5113

fgray@usgs.gov

Education

M.S., 1982 Geology - Univ. of Mass., Amherst, M.A

B.A., 1976 - Earth Science & Anthropology - Univ. of Calif., Santa Cruz, CA.

Current Activities

• Global Mineral Resource Assessment project
• Assessment Techniques for Concealed Mineral Resources project
• Development of Mineral Environmental Assessment Methodologies

Experience

2003-present

• Complex systems analysis of basin margins in southwestern North America project. Task leader: Chemical transport properties of basin marginal zones. In southeastern Arizona known contaminants stemming from past mining activity and industrial manufacturing centers have degraded or threaten the limited existing water resources. Factors such as precipitation rates, mountain-front structures, slope dynamics, soil type, riparian floodplain structure, and anthropogenic influences act as controls in the edges of mountain ranges to facilitate or inhibit the release, transport, and buffering of metal-enriched water moving down gradient in the arid Southwest.
• Complex systems analysis of basin margins in southwestern North America project. Task leader: Models of physical properties of basin marginal zones (Hydrogeology analysis of the San Pedro River, Sonora US/Mexico Borderlands). The intent of this task is to carry out cooperative geologic studies of selected regions of the economically important and environmentally diverse Cananea-Nogales quadrangles.  This research is specifically designed to develop hydrogeologic models from detailed geologic map data, experimental/leading edge geophysical and remote sensing tools and techniques.
• Pathways of Metal Transfer from Mineralized Sources to Bio-receptors project. Task Leader: Transport and Speciation of Metals in Particulate Phases in the Southwest US. This task proposes to develop criteria for and implement sampling and analysis of metals in a variety of particulate phases in the semiarid southwestern United States to create a more complete and dynamic model of the release, transport, and exposure cycles of metals from abandoned mine lands.

1996-2003

• Southwest Mineral and Environmental Investigations Project:  Task 3: Hydrogeologic Framework of the US –Mexico Borderlands (Geochemistry of Surface and Shallow Alluvial Groundwater in the Patagonia Mountains). This study involved understanding the influences of Laramide-age intrusives and associated mineral deposits on the local surface and groundwater regimes in the semi-arid to arid conditions of the US Southwest. Understanding the groundwater flow rates and neutralization- absorption –dilution phenomena occurring between low pH, metal-laden waters and the alkaline geological environment within shallow alluvial pathways is key to understanding and modeling the downstream impacts of acid drainage from abandoned metal mines and mineralized areas
• (Geologic Framework of the Cananea-Nogales Quadrangle, US/Mexico Borderlands).
  The intent of this project was to carry out cooperative geologic studies of selected regions of the economically important and environmentally diverse Cananea-Nogales quadrangles as a first step in improving the geology, geochronology, and regional geochemical and mineral resource data along the US/Mexico border.  Regional mapping and isotopic age dates are redefining and extending heretofore-unrecognized Laramide-age units in northern Sonora-Arizona border area.