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Full-Text Articles in Physical Sciences and Mathematics

Regional Hydrothermal Alteration Of The Leadville Limestone (Mississippian) Of Central Colorado, L. V. Benson Jan 1973

Regional Hydrothermal Alteration Of The Leadville Limestone (Mississippian) Of Central Colorado, L. V. Benson

United States Geological Survey: Staff Publications

Massive metallic-sulfide deposits were implaced in the Leadville Limestone {Mississippian) of Central Colorado less than 70 million years ago. The thermal fluids which precipitated ore at Gilman, Colorado have regionally altered the Leadville Limestone. The sequence of alteration began with the recrystallization of limestone to a dark medium~grained dolomite containing a homogeneous distribution of Fe. This Was followed by partial recrystallization of the medium-grained dolomite to coarse-clear dolomite which contains an inhomogeneous distribution of Fe. The resulting banded rock is known as "zebra rock" . Precipitation of Si0 2 (jasperoid) occurred next. The jaspe=oid formed prior to the deposition of …


The Aerosphere As A Network Connector Of Organisms And Their Diseases, Jeremy D. Ross, Eli S. Bridge, Diann J. Prosser, John Y. Takekawa Dec 200

The Aerosphere As A Network Connector Of Organisms And Their Diseases, Jeremy D. Ross, Eli S. Bridge, Diann J. Prosser, John Y. Takekawa

United States Geological Survey: Staff Publications

Aeroecological processes, especially powered flight of animals, can rapidly connect biological communities across the globe. This can have profound consequences for evolutionary diversification, energy and nutrient transfers, and the spread of infectious diseases. The latter is of particular consequence for human populations, since migratory birds are known to host diseases which have a history of transmission into domestic poultry or even jumping to human hosts. In this chapter, we present a scenario under which a highly pathogenic avian influenza (HPAI) strain enters North America from East Asia via postmolting waterfowl migration. We use an agent-based model (ABM) to simulate the …