Geology topics

Research about White Mountains

Source-linked reports with geographic coverage including White Mountains.

4 recordsLinked to original sources

USGS2019

Using a mechanistic model to develop management strategies to cool Apache Trout streams under the threat of climate change

User‐friendly stream temperature models populated with on‐site data may help in developing strategies to manage temperatures of individual stream reaches that are subject to climate change. We used the field‐tested Stream Segment Temperature model (U.S. Geological Survey) to simulate how altering discharge, groundwater input, channel wetted width, and shade prevents the temperatures of White Mountain, Arizona, stream reaches from exceeding the thermal tolerance of Apache Trout Oncorhynchus apache , both under existing conditions and under a climate change scenario. Simulations suggested increasing shade, either through streamside planting of specific numbers and species of plants or by other means, would be most effective and feasible for cooling the stream reaches we studied. Ponderosa pine Pinus ponderosa and Douglas fir Pseudotsuga menziesii provided the most shade followed in order by Engelman spruce Picea engelmannii , Bebb's willow Salix bebbiana , Arizona alder Alnus oblongifolia , and finally coyote willow Salix exigua . Vegetation survival depends on the appropriateness of site conditions at present and under climate change, and planting in buffer strips minimizes additional water removal from the watershed through evapotranspiration. Alternative shading options, including thick sedge growth, shade cloth, or felled woody vegetation, may be considered when environmental conditions do not support plantings. Increasing groundwater input can cool streams, but additional sources are scarce in the region. Decreasing the width‐to‐depth ratio would succeed best on reaches with widths greater than 2.0 m. Increasing discharge from upstream may lower water temperature on reaches with an initial discharge greater than 0.5 m 3 /s. Existing models provide suggestions to cool stream reaches. Further development of accessible software packages that incorporate evaporation, fragmentation, and other projected climate change effects into their routines will provide additional tools to help manage climate change effects.

Arizona↗

USGS1973

Granitic rocks of the White Mountains area, California-Nevada: Age and regional significance

Potassium-argon ages have been determined on 25 biotite and hornblende samples (four coexisting biotite-hornblende pairs were dated) from a number of granitic formations in the more than 500 sq mi of dominantly granitic outcrop in the White Mountains. These new data, together with earlier published radiometric ages, indicate a group of plutons about 70 to 85 m.y. old, a single body about 210 m.y. old, another that may be about 225 m.y. old, and several between 130 and 185 m.y. old. Evidence of intrusion is lacking in the intervals of about 90 to 130 m.y. and 185 to 200 m.y. The oldest age, about 226 m.y., may represent the chance preservation of a “primary” hornblende in a body in which the dark minerals are largely recrystallized and their radiometric ages reset. This age suggests that Triassic magmatism may be more widespread along the eastern margin of the Sierra Nevada batholith than had previously been considered. The radiometric age data from the White Mountains, together with similar data from northwestern and north-central Nevada and abundant data from the central Sierra Nevada, suggest essentially continuous, albeit irregular, magmatic activity from Triassic to the end of Cretaceous, except for periods of little or no activity in earliest Jurassic and earliest Cretaceous. Episodes of magmatic activity may, and probably do, characterize specific areas, but when sufficiently large blocks of the Sierra Nevada batholith are considered, the sum of the episodes approaches a continuum.

California, Nevada↗

USGS1972

Floods of August 1967 in east-central Alaska

East-central Alaska had record floods near Fairbanks following extensive rains of August 8-20, 1967. Precipitation during this period totaled as much as 10 inches, which is close to the average annual precipitation for this area. The most extensive flooding occurred in the White Mountains northeast of Fairbanks and along the major streams draining those mountains. Some of the major streams flooded were the Salcha, Chena, Chatanika, Tolovana, and lower Tanana Rivers, and Birch Creek west of Circle. Peak discharges on some streams in the flood area were from two to four times the probable 50-year flood. The peak discharge of 74,400 cubic feet per second of the Chena River at Fairbanks, from 1,980 square miles of drainage area, was 2.6 times the 50-year flood. The rise of ground-water levels in the Tanana River flood plain to the land surface during the flood caused foundation failures and prevented drainage of subsurface structures. Above-normal ground-water levels existed until the middle of September. Total flood damage was estimated in excess of $85 million. Six lives were reported lost, and about 12,000 persons were evacuated during the flood. This report has been prepared to furnish hydrologic data for development planning. Included are discussions of antecedent streamflow, meteorology of the storm, descriptions of floods, flood damage, flood frequency, ground-water conditions, and stages and discharges of major streams for August 1967.

Alaska↗

USGS1967

Enclosed bark as a pollen trap

Counts were made of pollen in traps formed by enclosed bark in two remnants of bristlecone pine, Pinus aristata Engelm., from the White Mountains of east-central California. The traps, dated by tree-rings at A.D. 350 and 1300 B.C., contained a major complex of pine-sagebrush pollen and traces of other species, representing the equivalent of the present vegetation.

California↗