Ecology, Environment and Conservation Paper

TYPE OF NICKEL LATERIZATION, LASOLO FRACTURE AND MOLLASE DEPOSITS OF SOUTHEAST SULAWESI, INDONESIA

Adi Tonggiroh, Asri Jaya and Ulva Ria Irfan

Abstract

The contact of ultramafic rocks distribution, metamorfpompangeo and mollase deposit are restricted by the structure of lasolo fracture with relatively direction of the northwest to the southeast, produce nickellateritic deposit with normal type of laterization, infill fractures and colluviums laterization. Normal type following the principle of horizontal-vertical laterization, infill fractures are characterized by supergene enrichment in ultramafic rock fractures and contamination laterization by collovium deposit. A field observation shows that horizontally the distribution of nickel- lateritic deposit is relatively more in contact with metamorphic rocks, sediments and molasses deposit. This distribution restrict beliefs to interpret the normal type in exploration stage to nickel- lateritic deposit which have perfective value levels quite low (< 1%), if linked to the needs of the value of nickel content at the time, but on the type of infill fractures and colluviums has an average of Ni over 2%. This research is a study of some exposure data, drill point data and regional geology is closely related to the regional fracture structure Lasolo, it is aimed to determine the statistical correlations of laterization type by applying drilling method, thin section, x-ray fluorescence and cluster analysis approach. The result of research can be concluded that normal laterization following the flow of ground water that penetration is limited by the fracture structure of lasolo, it formed rock fractures and accompanied by the flow of ground water and occurs laterization process, ultramafic rocks when undergoing a laterization process is restricted by the closure of molasses deposit so laterization formed more easily saprophyte layer compared to limonite.