Publications

Chromite investigations of the U. S. Geological Survey since 1939 indicate that economic deposits of chromite rich in normative spinel ((Mg, Fe)Al 2 O 4 ) occur in peridotites which are closely associated with gabbro; high-chrome chromites occur in feldspar-free peridotites; and chromites rich in both normative chromite ((Mg, Fe)Cr 2 O 4 ) and magnetite (FeFe 2 O 4 ) are found in the pyroxene-rich

The natural subterranean reservoirs formed by the porous and permeable rocks differ from surface reservoirs chiefly in that they have complex structure and great internal resistanc• to the How of water. Their full utilization requires systematic development based on the geology and hydrology of the aquifer and the principles of hydraulics distinctive of ground water. The methods of increasing rech

No abstract available.

The principal aquifer in the Orlando area consists of 900 feet or more of permeable artesian limestones of upper and middle Eocene age. As in most other parts of the Florida peninsula, these limestones are overlain by the Hawthorn formation of Miocene age which contains relatively impervious beds. The Hawthorn at Orlando is 45 to 200 feet thick and prevents or retards natural recharge to the lime.

The cotangent ruler is a device for measuring directly the dip of contoured surfaces, or, conversely, for constructing contours that represent planes of known dip. It greatly simplifies the graphic solution of problems in structural geology, and has several specialized applications to problems commonly encountered in mining geology and areal geologic mapping.

Records obtained by the Geological Survey, United States Department of the Interior, and the Geological Division, Kentucky Department of Mines and Minerals, indicate that industries at Louisville pumped about 62 million gallons of water per day from wells in 1943. This was over 20 million gallons a day more than the natural recharge to the glacial outwash sand and gravel from which the wells draw

Extensive geological investigations of domestic deposits of quartz crystals were undertaken by the Geological Survey of the United States Department of the Interior in the fall of 1942 in response to the urgent demand for crystals for war purposes. The work was continued throughout 1943 and took survey geologists into some 20 states in which over 1,400 deposits or reports of deposits were examined

Artificial recharge by water spreading is practiced in several places in New Jersey. Rates of recharge ranging from 3,000 to 125,000 gallons per acre per day have been measured at the Perth Amboy Water Works, where artificial recharge of the Old Bridge sand, of upper Cretaceous age, has been practiced for more than 40 years. At the Duhernal development, which also draws from the Old Bridge sand, f

Hydrothermal alteration of the quartz monzonite host rock in the Castle Dome copper deposit consists of three phases. Very weak propylitic alteration of biotite and plagioclase occurs in the marginal part of the mineralized area. Where mineralization is stronger most of the plagioclase and some of the orthoclase and biotite are replaced by a montmorillonitetype clay, resembling beidellite, and hyd

No abstract available.

No abstract available.

No abstract available.