scholarly journals Karakteristik Alterasi dan Mineralisasi Tipe Epitermal Daerah Gunung Budheg dan Sekitarnya, Tulungagung, Jawa Timur

EKSPLORIUM ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 1
Author(s):  
Rinal Khaidar Ali ◽  
Tri Winarno ◽  
Muhammad Ainurrofiq Jamalulail

ABSTRAK Penemuan bongkah-bongkah vuggy quartz di sekitar Desa Pojok, daerah Gunung Budheg, Tulungagung, Jawa Timur, mengindikasikan adanya proses endapan mineral di daerah tersebut. Tujuan penelitian ini adalah untuk membahas lebih detail karakteristik alterasi dan mineralisasi serta tipe endapan mineral di daerah penelitian. Metode penelitian berupa pengamatan lapangan dilengkapi dengan analisis laboratorium petrografi, X-ray Difraction (XRD) dan mineragrafi. Satuan batuan di daerah penelitian tersusun atas enam satuan litologi yaitu satuan intrusi dasit, satuan lava andesit, satuan breksi andesit, satuan breksi polimik, satuan batugamping terumbu dan aluvium. Tipe alterasi di daerah penelitian adalah alterasi profilitik, argilik, argilik lanjut, dan silisifikasi. Alterasi profilitik dicirikan oleh melimpahnya mineral klorit. Alterasi argilik dicirikan dengan melimpahnya mineral kaolin, sementara argilik lanjut dicirikan oleh hadirnya mineral kaolinit dan alunit. Alterasi silisifikasi yang dicirikan oleh melimpahnya mineral kuarsa. Mineral logam yang ditemukan di daerah penelitian didominasi oleh kelompok mineral sulfida seperti kovelit, kalkosit, enargit, kalkopirit, pirit,  dan jarosit. Emas native ditemukan berasosiasi dengan enargit. Sistem endapan mineral pada daerah penelitian merupakan sistem epitermal sulfidasi tinggi dicirikan oleh kuarsa berongga (vuggy quartz) yang termineralisasi dan kehadiran mineral kaolin sebagai mineral hasil alterasi.ABSTRACT The discovery of vuggy quartz boulders around Pojok Village, Gunung Budheg area, Tulungagung, East Java, indicates the presence of mineral deposits process in this area. This study aims to discuss detailed characteristics of alteration and mineralization as well as mineral deposits type in the study area. The research methods are field observations completed with petrography, X-ray Diffraction (XRD), and mineragraphy laboratory analysis. The rock unit in the study area consists of six lithology units, a dacitic intrusion, andesitic lava, andesitic breccia, poly-mix breccia, reef limestone, and alluvium. The study area's alteration types are profilitic alteration, argillic alteration, advanced argillic, and silicification alteration. The profilitic alteration characterized by the abundance of chlorite minerals. The argillic alteration characterized by the abundance of kaolin minerals, while the advanced argillic alteration by the presence of kaolinite and alunite minerals. The silicification alteration characterized by abundance quartz minerals. The metallic minerals dominated in the area are sulfide minerals such as covellite, chalcocite, enargite, chalcopyrite, pyrite, and jarosite. The native gold found in an association with enargite. The study area's mineral deposit system is an epithermal high sulfidation system characterized by mineralized vuggy quartz and the presence of kaolinite mineral as an alteration mineral.

Author(s):  
Anna Caroline Andrade Pinto ◽  
Tiago Felipe Arruda Maia

Many of the studies about mineral deposits are bringing great information to the scientific community, providing, for example, general characteristics of these deposits, possible source areas and its used in some cases as prospective tools to help in geological mapping. In this way, this study aimed to characterize the alluvial secondary deposits of columbite-tantalite that were found near vicinal 12, about 50km north/northeast of Rorainópolis city, between the BR-174 and BR-210 roads, in the state of Roraima (Brazil), bases on 4 samples that were brought by a resident of the region. To fulfill these objectives, some chemical and mineralogical methods were performed, like: magnetic separation, X-ray diffraction, X-ray fluorescence and petrographic description. The deposits of the region end up being characterized by having a large amount of Fe and Ti (mostly), containing in some places also a large concentration of Niobium and Tantalum. Not all samples have columbite-tantalite, showing that their concentration in some areas of the deposit is quite low. There are samples with less than 1% Nb and Ta and also samples with more than 20% Nb and 6% Ta concentration. These minerals were poorly transported, being identified by the degree of roundness and granulometry of the samples. A weathering cap on some minerals could also be verified. This research work turned out to be relevant, as it provides new data that add to the knowledge of the mineral potential, which has not been fully explored yet.


1977 ◽  
Vol 86 (4) ◽  
pp. 525-540 ◽  
Author(s):  
David J. Lim ◽  
William H. Saunders

A total of 32 otosclerotic stapes is thin-sectioned without decalcification and examined using transmission and scanning electron microscopes, with a nondispersive x-ray analyzer attached to the latter. These otosclerotic stapes are classified as spongiotic, sclerotic, or preotosclerotic, according to their pathologic characteristics and state of mineralization. Either diffuse or patchy demineralization in the ground substance appears to be the initial stage of otosclerosis, and this area coincides with preotosclerotic lesions (also known as blue mantle) in light microscopy. Therefore, it is interpreted that demineralization precedes the destruction of ground substance in the preotosclerotic lesion. Bone mineral deposits in new otosclerotic bone appear to be related to the collagen fibrils that are embedded in the ground substance. No mineral deposit could be seen without the ground substance deposition; therefore, it is suggested that this ground substance is the single most important factor in the poor mineralization of the otosclerosis. The sclerotic lesions are well mineralized and show a typical pattern of hydroxyapatite by x-ray diffraction study. We could not confirm the notion that the sclerotic lesion is hypermineralized as compared to the normal stapes. The spongiotic lesions are poorly mineralized, with low calcium salt. Using the Ca/P ratio and x-ray diffraction pattern as criteria, it was determined that spongiotic lesions belong to unstable, immature bone.


1966 ◽  
Vol 3 (4) ◽  
pp. 350-378 ◽  
Author(s):  
Charles C. Capen ◽  
Clarence R. Cole ◽  
John W. Hibbs

Experimental hypervitaminosis D was produced in cows by the daily feeding of 30 million U.S.P. units of vitamin D for varying periods of time. Cardiovascular mineralization was not present after 7 days, but was observed after 10 days and became extensive and widespread after 21 and 30 days. Pregnant cows developed more severe lesions than non-pregnant ones. In the heart, the lesions were more severe on the left side, and consisted of subendocardial mineralization and hemorrhage. In the elastic arteries, the degree of mineralization was maximal proximally, and diminished in severity distally. In the muscular arteries, the mineral deposits when confined to the media were accompanied by a proliferative intimal reaction. The veins were less severely affected than the arteries. Histochemically the mineral deposits contained abundant calcium and phosphorus. X-ray diffraction studies indicated the principal inorganic product of the vitamin D-induced mineralization was a carbonate hydroxyapatite, comparable in crystallochemical characteristics to that of bone.


2021 ◽  
Vol 9 (2) ◽  
pp. 179-186
Author(s):  
Hasbi Bakri ◽  
Harwan Harwan ◽  
Alam Budiman Thamsi ◽  
Irzal Nur ◽  
Firdaus F ◽  
...  

Iron ore is the second most abundant metal on earth. The characteristics of this iron ore usually consist of iron ore carrier minerals associated with other minerals. One area that has iron ore prospects is the Tanjung area, Bontocani District, Bone Regency. The purpose of this study was to determine the types of iron ore carrier minerals and their associations, mineralization characteristics and paragenesis of iron ore carrier minerals. The data collection technique is carried out directly in the field by taking random samples in the field according to field conditions. Laboratory analysis uses mineragraphic analysis to determine iron ore carrier minerals and their associated minerals and X-Ray Diffraction analysis to determine iron ore carrier minerals that are not identified by mineragraphic analysis. From the results of the study found iron ore carrier minerals magnetite, goethite and hematite and their associated minerals in the form of sulfide minerals in the form of pyrite, covelite and braunite. The iron ore textures found are replacement and intergrowth textures. Paragenesis of mineral deposits formed successively are magnetite, hematite, pyrite, cuprite, braunite and goethite.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


Author(s):  
James A. Lake

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.


Author(s):  
C. Wolpers ◽  
R. Blaschke

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.


Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.


Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.


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