Exploration rock geochemistry for Pinnacles-type mineralization at Broken Hill, N.S.W., Australia

Geochemical responses in weathered and oxidized surface metasedimentary rocks associated with stratiform lead-zinc mineralization at Stirling Hill (6 km west of Broken Hill) are compared with the geochemical responses in fresh drill core from an equivalent lithostratigraphic section with stratiform lead-zinc mineralization at the Pinnacles Mine (8 km south of Stirling Hill). Mineralization is interpreted as being volcanic exhalative and it lies within highly metamorphosed (sillimanite grade) rocks of the Willyama Supergroup.Surface rocks were classified into groups by discriminant analysis using drill core data from the Pinnacles Mine as the initial training set. The behaviour of elements in surface rocks varies with the rock group but Zn, Pb, Mn, Fe, and Co are leached from all surface rocks relative to fresh drill core.Nothwithstanding the leaching effects of weathering, common geochemical responses to mineralization have been identified in drill core and surface rocks. Coincident positive anomalies for Zn/Ba and Fe/(Na × Ba) ratios and negative anomalies for Na/(Mn × Ca) ratios uniquely define mineralization in both weathered surface rocks and in fresh drill core.The results demonstrate that the pattern of geochemical responses to Pinnacles-type stratiform volcanic-exhalative mineralization in surface rocks has survived the intensive weathering regime in the Broken Hill region.     

Some scientific and applied problems of supergene geochemistry in the U.S.S.R.

Demands of modern human society require a wide application of the principles of hypergene geochemistry in order to explore for deeply buried minerals, protect the environment, assist in some medical and biological problems, etc.; such is impossible without a sound theoretical basis for this science. It is necessary that the processes associated with deep weathering be investigated, as well as the mechanisms of element transport (electrochemical transfer, vapor transport, migration of elements in pore water, etc.) and the formation of geochemical halos in various secondary environments. More effective techniques (based on chemical extractions, artificial sorbents, biological methods, etc.) must be developed in order to make further advances in all aspects of applied supergene geochemistry. Toward this end, the successful application of artificial sorbents to exploration and environmental problems is illustrated, and “geochemistry of technogenesis”, one of the main branches of hypergenesis, is discussed and shown to be presently at the stage of “geochemical inventory”. Technogenic geochemistry consists of detailed data collection for all elements and, primarily, geochemical mapping of affected environments. One of the objectives of technogenic geochemistry is the development of the theory and implementation of practical measures necessary to utilize the most efficient geochemical systems in the various natural situations affected by man. Lack, or excess, of certain chemical elements in the environment are important geochemical factors to be considered in the study of endemic disease (i.e. “medical geochemistry”). Studies are illustrated which show a general tendency for areas with higher percentages of cancer to have higher average contents of Mn, Pb and Co, but lower amounts of Cu, compared with regions with moderate oncological disease rates. The importance of studying the modes of occurrence of chemical elements in the secondary environments is stressed. By the end of this century the role of environmental geochemistry is expected to be substantially more important and will require scientists specifically trained in this subject.     

Development of geological research in U.S.S.R Academy of Sciences and U.S.S.R. Ministry of Geology and Mineral Reserves

On October 12, 1962, a joint session of the Presidium of the U.S.S.R. Academy of Sciences and the Collegium of the U.S.S.R. Ministry of Geology and Mineral Reserves adopted a resolution “On the present state of the geological sciences in the U.S.S.R. Academy of Sciences and the U. S. S. R. Ministry of Geology and Mineral Reserves and their prospects for the future.” Important contributions of Russian geologists are acknowledged, but attention is drawn to many shortcomings. Future goals of geological study and work are given in detail. Twenty-one lines of research to be concentrated on are given, covering all phases of geology, geophysics, and geochemistry. In discussing the failings of the geological profession in Russia, it is of interest to note the following comment: “Geological research in other countries is still insufficiently studied and applied, and we are not making adequate use of geologic information from abroad.” The list of the Russian geologists' shortcomings sounds vaguely familiar. —J. R. Hayes     

Background radiation in the Albuquerque,New Mexico,U.S.A., area

Background radiation levels in the Albuquerque, New Mexico, area are elevated when compared to much of the United States. Soil K, U, and Th are somewhat elevated compared to average values in this country and generate roughly 60 mrem per year to the average resident. Cosmic ray contribution, due to the mean elevation of 5,200 ft above sea level, is 80 mrem/yr—well over the average for the United States. Thirty percent of the homes in Albuquerque contain indoor radon levels over the EPA action level of 4 pCi/ compared to 10–12 percent of homes for the entire United States. Indoor radon contributes about 100–300 mrem/yr. Food, beverages, and x-ray doses are assumed at an average-equivalent for the United States and locally yield 96 mrem/yr. Total contributions from other minor sources (color TV, coal, weapons fallout, etc.) are under 10 mrem/yr. Thus total background radiation received by Albuquerque residents is about 330–530 mrem/yr, well in excess of the rest of the United States. The spread in mrem values is due to variations in the contribution from indoor radon.Douglas G. Brookins, Professor of Geology and former Chairman of the Department, 1976–1979, passed away unexpectedly on April 30, 1991. He was a man of passion, intellect, and conviction. He left us at the peak of his productive career, but he leaves behind a legacy of exceptional accomplishments and contributions to his friends, family, students, and profession. He was a member of the Faculty Senate at the time of his death and had served two previous terms in 1984 and 1986.Doug's academic accomplishments were of world class, beginning with an AB degree, Summa Cum Laude, from U.C. Berkeley in 1958 and a PhD from MIT in 1963. He came to UNM as a full professor in 1971, having previously served at Kansas State University, and built a first class program in isotope geochemistry. He wrote five books and had a sixth in progress, edited several others, and authored or coauthored approximately 500 technical papers, book chapters, and reports.—Bruce M. Thomson and Wolfgang E. Elston, University of New Mexico.     

Soil geochemistry of Mother Lode-type gold deposits in the Hodson mining district, central California, U.S.A.

The Hodson mining district is in the westernmost foothills of the Sierra Nevada in California, about 17 km west of the town of Angels Camp. This district is part of the West Gold Belt, which lies about 12–16 km west of, and generally parallel to, the better known Mother Lode Gold Belt in central California. The district produced several million dollars worth of Au between about 1890 and 1940.