Publications

Epidote is a major magmatic mineral in tonalite and granodiorite in a belt coextensive with the Mesozoic accreted terranes between northern California and southeastern Alaska. Textural and chemical evidence indicates that epidote crystallized as a relatively late but magmatic mineral that formed through reaction with hornblende in the presence of a melt phase. The observed relations concur with ex

Accessory chromite in dunite shows a variety of textures that indicate alteration. One group, type A, consists of four types of chromite: clean chromite; lattice chromite, in which the invading chlorite occurs along three directions in the (100) plane; optically zoned chromite; and poikiloblastic chromite. Most of type A chromites are surrounded by chromian clinochlore. The other group, type B, co

A mineral-resource survey was made of the Devils Den Roadless Area, Vermont, Geochemical sampling found traces of gold, copper, barium, lead, molybdenum, silver, tin, and thorium in rocks, stream sediments, and panned concentrates, but not in sufficient quantities to identify any resource potential. The only apparent resources are nonmetallic commodities including abundant rock suitable for crushi

On the basis of mineral-resource survey the Bread Loaf Roadless Area, Vermont, is considered to have probable resource potential for the occurrence of volcanogenic massive sulfide deposits of copper, zinc, and lead, particularly in the north and northeastern section of the roadless area. Nonmetallic commodities include minor deposits of sand and gravel, and abundant rock suitable for crushing. How

A mineral-resource survey of the Bristol Cliffs Wilderness, Vermont, indicates that there is little promise for the occurrence of metallic mineral resources within the wilderness. The only apparent resources are nonmetallic commodities including rocks suitable for construction materials and silica sand, and small amounts of peat and sand and gravel; however, these commodities are found in abundanc

No abstract available.

Introduction Lithotectonic, mineralogical, and geochemical data on two silver- and base metal-bearing deposits from Peru and two from Mexico are compiled to facilitate comparisons with other epithermal deposits. Silver and base metal-bearing deposits of Mexico and Peru constitute an important portion of the world silver production derived from shallow, vein-type deposits hosted in volcanic rocks.

No abstract available.

No abstract available.

Major world resources of chromium, a strategic mineral commodity, are described in this summary report of information in the International Strategic Minerals Inventory {ISMI}. ISMI is a cooperative data-collection effort of earth-science and mineral-resource agencies in Australia, Canada, the Federal Republic of Germany, the Republic of South Africa, and the United States of America. This report,

Solubilities of halite in the ternary system NaCl-CsCl-H2O have been determined by the visual polythermal method at 1 atm from 20 to 100 °C along five constant CsCl/(CsCl + H2O) weight ratio lines. These five constant weight ratios are 0.1, 0.2, 0.3, 0.4, and 0.5. The maximum uncertainties in these measurements are ±0.02 wt % NaCl and ±0.15 °C. The data along each constant CsCl/(CsCl + H2O) weight

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 lower mafic