PENAFSIRAN STRUKTUR BAWAH PERMUKAAN DAERAH BANGKA UTARA, BERDASARKAN ANOMALI GAYA BERAT

W. H.Simamora

doi:10.33332/jgsm.geologi.v17i3.287

Authors

W. H.Simamora Pusat Survei Geologi Author

DOI:

https://doi.org/10.33332/jgsm.geologi.v17i3.287

Abstract

The gravity measurement carried out in the North Bangka Quadrangle has produced 1:250,000 Bouguer anomaly, regional and residual gravity maps. Bouguer anomaly values range from 5.0 to 39.0 mgal, regional anomalies arebetween 13.0 until 35.0 mgal and residual anomalies are from -7.0 to 10.0 mgal. The Bouguer anomalies aredivided into three types, i.e : low, medium and high, while the residual anomaly is categorized as positive and negativeareas.The modelling result of three sections of residual anomaly shows that the density of 2.69 gr/cc and interpreted asPemali Complex belongs to the basement in the area. This basement is Pemali Complex which is intruded by rocks with densities of 2.54 ; 2.56 and 2.58 gr/cc and indicated as granitic intrusion. Boundary between Pemali complex, Tanjunggenting formation and granitic intrusion is fault contact. This contact could be potential for secondary tin deposit resulted from weathered granite.

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Keywords : gravity, residual anomaly, density, tin deposit, Bangka

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