Publications

The New River enters the United States at Calexico, Calif., after it crosses the international boundary. Water-quality data from routine collection indicated that the New River was degraded by high organic and bacterial content. Intensive sampling for chemical and physical constituents and properties of the river was done May 9-13, 1977, to quantify the chemical composition of the water and to ide

No abstract available.

Obsidian hydration dating of volcanic events had been compared with ages of the same events determined by the 14C and KAr methods at several localities. The localities, ranging in age from 1200 to over 1 million yr, include Newberry Craters, Oregon; Coso Hot Springs, California; Salton Sea, California; Yellowstone National Park, Wyoming; and Mineral Range, Utah. In most cases the agreement is quit

Vitrinite reflectance measured in immersion oil (Ro) on kerogen extracted from hydrothermally altered mudstones in borehole M-84 at the Cerro Prieto geothermal field exhibit an increase in mean reflectance (Ro) from 0.12 per cent at 0.24 km depth to 4.1 per cent at 1.7 km depth. Downhole temperatures measured over this interval increase from about 60° to 340°C. These Ro data plotted against temper

Tectonic tilt at the Salton Sea was calculated by differencing lake-level measurements from two points on the sea. During the past 26 years, tilting was down toward the southeast. By 1970 differential vertical movement amounted to 110 millimeters between two gages situated 38 kilometers apart on the southwest shore. A reversal in tilt direction in late 1972 has diminished the net differential vert

No abstract available.

Rocks deposited near sea level under marine, estuarine, and lacustrine conditions, and located along the course of the lower Colorado River from the mouth of the Grand Canyon as far as the Mexican border, have been displaced to present positions as high as 880 m a.s.l. and as low as 1600 m b.s.l. The rocks include the marine and estuarine Bouse Formation and the lacustrine or marine Hualapai Limes

Precise geodetic surveys since 1972 indicate that significant vertical deformation of the land surface continues in Imperial Valley, California. Measured vertical changes as great as 3-5 cm per year indicate that two types of tectonic movement are occurring: (1) a downward regional tilt of the valley surface from the Mexican border northward toward Salton Sea, and (2) a deepening of the structural

Evaporation from Salton Sea, Calif. was computed for a 539-day period between duly 14, 1967, and January 2, 1969, by use of energy-budget, mass-transfer, and water-budget methods. The total evaporation computed by the three methods agreed within 5 percent. For computing evaporation by the mass-transfer method, vapor pressure measured at raft stations on the sea was considered to be more representa

Evaporation from the Salton Sea, Calif., was computed for a 539-day period between July 14, 1967, and January 2, 1969, by use of energy-budget, mass-transfer, and water budget methods. The total evaporation computed by the three methods agreed within 5 percent. The values of heat transfer to and from the bed were used in the energy-budget computations. Monthly evaporation computed by the energy-bu

No abstract available.

During 1969 and 1970, surveys of the endangered Yuma Clapper Rail were conducted using taped calls to elicit responses from the birds. During the two summers, more than 158 Yuma clappers were located in cattailtule marshes along the Colorado River south of Needles, California, to the International Boundary, a distance of about 240 miles. Clappers (probably of the same race) were also found in estu