GEOCHEMICAL STUDY OF STREAM DEPOSITS IN THE SOUTH PART OF BLITAR REGENCY, EAST JAVA PROVINCE

• Main Author: Nanda Suratman, Calvin
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/40166
• Institution: Institut Teknologi Bandung

datum WGS1984, with research area of 248.5 km2. According to the East Java’s physiographic zone, the research area is part of the East Java Southerns Mountain Zone which has the potential of preserving precious metal and base metal minerals. Stratigraphy of the research area based on literature from old to young consists of 6 units, namely Mandalika Formation, Campurdarat Formation, Intrusion Rocks, Nampol Formation, Wonosari Formation, and Alluvium. The study aims to delineate metal prospect areas by analyzing the relationship between geology and geochemistry of the research area. The geochemical data analyzed consists of concentration dataset of Ag, Mo, Pb, Zn, Mn, Cu, Au and As elements from stream deposit samples. Geochemical analysis is carried out in two stages which are univariate analysis, aimed to determine the element threshold values and multivariate analysis, aimed to determine the element association groups. Univariate analysis carried out produces element threshold values as follows; Ag is 0.06 ppm, Mo at 5.89 ppm, Pb is 17.8 ppm, Zn is 232 ppm, Mn is 2883 ppm, Cu is 77 ppm, Au is 0.0733 ppm and As is 31 ppm. While the results of multivariate analysis show that there are two main groups of elemental associations in the research area, namely; Ag-Mo-Pb and Zn- Mn-Cu-Au-As. The mineralization types in the research area which obtained from that elemental association groups are Carlin Type and Epithermal. The relation between the results of geochemical analysis and the geological conditions of the research area are being used to determine the prospect zone. The prospect zone in this research area is divided into three groups, namely; the Ag-Mo-Pb prospect zone which is located on upstream of Ngrejo, Pasiraman, Kalibawang, Centung, Besole, and Sumberglagah areas; the Zn-Mn-Au-As prospect zone which is located on upstream of Sumberboto, Kepek and Sumberwringin areas; and the Cu prospect zone which is located on stream of Centung area.