Well-developed lava tree molds were formed during the September 1961 eruption along the east rift zone of Kilauea Volcano. The upright molds were produced where fluid lava, flowing through dense tropical forest, became chilled against the larger trees and tree ferns and later drained away. Where the lava ponded temporarily in a structural valley, tree molds more than 14 feet high mark the high level attained by the flow.

Hawaii↗

USGS1961

Magmatic differentiation in the Uwekahuna Laccolith, Kilauea Caldera, Hawaii

Petrographic and chemicoal studies of a suite of rocks from the Uwekahuna laccolith of Kilauea Volcano show that the original mafic tholeiitic magma differentiated into tholeiitic picrite, tholeiitic olivine gabbro, and an aphanitic rock approaching quartz-basalt in composition. Mechanisms involved were an initial gravity settling of olivine and a final filter pressing of the residual liquid. The range of composition represented by the rocks of the laccolith is as great as that found among all hitherto analysed lavas of the volcano.

Hawaii↗

USGS1961

Lava temperatures in the 1959 Kilauea eruption and cooling lake

The 1959 summit eruption of Kilauea Volcano, Hawaii, filled the crater of Kilauea Iki with a lake of lava 365 feet deep. Temperatures of the erupting basalt ranged between 1060° and 1190°C. Temperatures down a 12.7-foot-deep hole, drilled into the crust of the lake 5 months after cessation of eruptive activity, agree with calculated temperatures based on the heat equation. The cooling effect of rainfall is pronounced only in the upper 3½ feet of the crust.

Hawaii↗

USGS1957

Gravity prospecting for chromite deposits in Camaguey Province, Cuba

Detailed gravity surveys were made in Camaguey Province, Cuba, as part of a systematic exploration program conducted by the U. S. Geological Survey on behalf of the General Services Administration to locate deposits of refractory-grade chromite. During the period August 4, 1954, to April 5, 1956, a total of 41,921 gravity stations were established in nine areas embracing about 11.8 square miles in the Camaguey chromite district. The results of the surveys were used in connection with information obtained in geologic investigations to guide exploratory drilling.Gravimeters with low scale constants were used in making measurements sufficiently accurate to delimit anomalies as small as 0.5 gravity unit. The measurements were made over 20 X 40 and 30 X 60 meter grids and at stations 20 and 30 meters apart, respectively, along intermediate traverses in anomalous areas. Gravity differences were determined by single observations at individual stations, observing base stations hourly, and re-observing a few stations to check drift and accuracy of measurement. About 11 percent of the stations established had to be re-run because of errors in closure, microseisms, and instrument trouble.A large number of anomalies were found and evaluated according to geology, areal extent, and gravity relief. Depths to disturbing hypothetical bodies were computed to guide drilling. Test drilling of 106 positive anomalies revealed that ten features overlie deposits of chromite and 89 occur over bodies of other dense materials. The other seven anomalies were not explained by materials found in drilling. Core drilling on five of the chromite deposits revealed about 236,000 tons of chromite. An additional estimated 12,000 tons are contained in three deposits which were not blocked out. No estimate was made of the tonnage in two small deposits.

Camaguey↗

USGS1955

Is Carbon dioxide an ore-forming fluid under shallow-earth conditions?

A review of some of the physical-chemical properties of CO 2 and of the system CO 2 --H 2 O indicates that under some shallow-earth conditions CO 2 can exist as a separate phase with a density approximately that of water. The effect of dissolved neutral or acid salts on the solubility of CO 2 in H 2 O is not large. Carbonates, oxides, and silicates, through reactions with a CO 2 -saturated water phase, will eventually cause the disappearance of a CO 2 phase. The prevalence of CO 2 in the earth's crust is attested by its abundance in natural gases and fluid inclusions in minerals. Some of the characteristics of uranium ores of the Colorado Plateau are not incompatible with the assumption that deposition was from a fluid CO 2 phase.

Economic Geology↗

USGS1954

Some considerations regarding liquid inclusions as geologic thermometers

No abstract available.

Economic Geology↗