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Abstract

Studies were performed in the summer of 1989 in the vicinity of the Polish Polar Station at Hornsund, Svalbard, in an attempt to characterize the functioning of selected tundra soils in terms of bioenergetics. The intensity of bioenergetical processes in the soil was evaluated by the rates of O2 consumption and CO2 production, measured in the laboratory under controlled hydrothermic conditions. Soils metabolic processes are markedly correlated with soil water content and dependent upon soil structure, water capacity and character of plant cover. The strongest correlation was observed in the more aerated soils with small water capacity and without vegetation. The respiratory quotient (RQ) decreased with the growth of soil moisture content. Soil metabolic activity began directly after the summer melting of the ground, when the soil temperature reached 0°C, and ceased in autumn, when temperatures fell below 0°C again.

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Authors and Affiliations

Zofia Fischer
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Abstract

In the Motongkad prospect, East Bolaang Mongondow Regency, North Sulawesi Province, Indonesia, an epithermal gold mineralization occurred, hosted in andesitic-basaltic breccia, lava and tuff members the middle Miocene volcanic rock (Tmv). The Volcanic Rock is intruded by andesite dikes and contains fine quartz veins. Gold, silver, and pyrite found in the quartz veins.
This study consists of two main stages, field works and laboratory works. The field works were performed in whole area of the Motongkad prospect, where fresh and altered rock and mineralization samples were collected randomly, selectively, and systematically from outcrops as well as from a test pit. The laboratory works include petrography, X-ray diffraction (XRD), ore microscopy, and chemical analysis using the atomic absorption spectrometry (AAS) method.
The study area is arranged by three lithology units. Stratigraphically, the units are andesite rhyolite and tuff. The hydrothermal alteration in the study area are classified in five zones, namely: quartzsericite, quartz-sericite-clay, quartz-calcite-sericite-chlorite, quartz-calcite-sericite, and quartz-calcite- kaolinite. Motongkad prospect mineralization consists of two types, namely the vein type and the disseminated type. The ore minerals found in the Motongkad prospect are gold, pyrite, chalcopyrite, sphalerite, covellite, chalcocite, bornite and tennantite. We conclude that gold mineralization and its associated minerals in the Motongkad prospect are hydrothermal mineralization with epithermal characteristics.
Based on the results of mineragraphic analysis, there are two types of gold-bearing minerals found, namely native gold minerals and electrum, which are generally hosted by pyrite. Based on the distribution map of alteration and mineralization that has been made, it is recommended that the company wish to conduct mining with the highest gold content in the quartz-sericite and quartz-sericite- clay alteration zones, which are in the range of 0.83–1.07 g/t.
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Authors and Affiliations

Muhmammad Adam
1
Asri Jaya
1
Musri Mawaleda
1
Irzal Nur
2

  1. Earth and Environmental Technology Study Program, Geological Engineering Department,Faculty of Engineering, Hasanuddin University, Gowa, Indonesia
  2. Mining Engineering Department, Faculty of Engineering, Hasanuddin University, Gowa, Indonesia

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