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Geology topics

Michael Fleischer

Publications and source records attributed to Michael Fleischer.

At least 37 records · Page 2Linked to original sources
USGS1963

The abundance of scandium in volcanic rocks, a preliminary estimate

Using Rittman's classification to determine the clan, we suggest the following abundance figures: basalts (99), 38 p.p.m. Sc; andesites (72), 34 p.p.m. Sc; dacites (68), 21 p.p.m. Sc; rhyodacites (32), 14 p.p.m. Sc; quartz latites (14), 11 p.p.m; rhyolites (24), 5 p.p.m. The scandium was determined spectrographically on samples for which there were complete rock analyses. In addition we suggest that extrusive equivalents of peridotites should contain about 9 p.p.m. Sc; extrusive equivalents of perknites should contain about 30 p.p.m. Sc. We see no reason why these figures should not apply to the intrusive equivalents. We tentatively suggest a figure of 30 p.p.m. for Sc for the crust, using Poldervaart's suggested ratio of rock types.

Geochimica et Cosmochimica Acta↗
USGS1959

The geochemistry of rhenium, with special reference to its occurrence in molybdenite

Little has been added to our knowledge of the geochemistry of Re since the work of Noddack and Noddack in 1931, except that many determinations have been published of the Re content of molybdenite, the only present source. These determinations, 150 in all, have been assembled. The Re content of molybdenite ranges from none to 3,250 p.p.m. Re, and varies widely, even in samples from a single deposit. No generalizations are yet possible as to correlations of Re content with geological conditions of formation. Other possible sources of Re are considered briefly.

Economic Geology↗
USGS1955

Estimates of the abundances of some chemical elements and their reliability

During the past thirty years the development of improved methods of analysis, especially optical spectrography, x-ray spectrography, and colorimetric methods, has resulted in a wealth of new data on the abundances of many elements. Nevertheless, present estimates differ greatly in reliability; some, such as the estimate for bismuth, are based on very few actual determinations, whereas others, such as that for gallium, are based on analyses of many samples. This paper reviews the estimates of abundance for the elements bismuth, germanium, gallium, and yttrium, taken as examples to illustrate the wide variation in reliability. For gallium and yttrium, a study has been made of spectrographic analyses by four laboratories of more than 600 chemically analyzed rocks from many areas of the world. Comparison shows that these furnish valuable data on abundance, although attention must be directed to regional variation. The comparison also shows the need for continued interlaboratory standardization. The estimate for bismuth is based on so few determinations that no appraisal of its accuracy can be made. The estimate for germanium is based on very few determinations but is almost certainly of the right order of magnitude, though perhaps slightly too high. The estimates for gallium and yttrium, based on many determinations, are almost certainly of the right order of magnitude, though that for gallium may be slightly low and that for yttrium may be substantially low.

GSA Special Papers↗
USGS1950

A glossary of uranium- and thorium-bearing minerals

During 1980, an estimated 121 million gallons of water per day was pumped in a 26-county area in east-central Georgia from sand aquifers of Paleocene and Late Cretaceous age. Maximum withdrawals were at the kaolin mining and processing centers in Twiggs, Wilkinson, and Washington Counties, where water levels have declined as much as 50 ft since 1944-50. In the southern two-thirds of the study area, water levels have shown little, if any, change. Declining water levels and increasing competition for groundwater have caused concern over the adequacy of groundwater supplies. This report defines the areal extent and describes the geohydrology of the Paleocene-Upper Cretaceous aquifers of east-central Georgia, and evaluates the effects of man on the groundwater flow system. Geohydrologic data from four test wells indicate that the aquifers consist of alternating layers of sand and clay that are largely of deltaic origin. In the northern third of the study area, the confining unit between the Dublin and Midville aquifer systems is absent and the aquifer systems combine to form the Dublin-Midville aquifer system. The aquifer systems range in thickness from 80 to 645 ft and their transmissivities range from 800 to 39,000 sq ft/day. The hydraulic conductivity ranges from 15 to 530 ft/day. Wells yield as much as 3,400 gpm (gallons per minute). Chemical analyses of water from 49 wells indicate that water from both aquifer systems is of good quality except in the central part of the study area, where iron concentrations are as high as 6,700 micrograms/L and exceed the 300 micrograms/L recommended limit for drinking water. The principal recharge to the aquifer systems is from precipitation that occurs within and adjacent to the outcrop areas. The principal discharge is to streams in the outcrop area. (Author 's abstract)

Circular↗