GUNUNGAPI BAWAH LAUT KAWIO BARAT, PERAIRAN SANGIHE, SULAWESI UTARA: AKTIVITAS HIDROTERMAL DAN MINERALISASI
Abstract
Kata kunci: INDEX-SATAL 2010, aktivitas hidrotermal, ROV, asap hidrotermal, gelembung cairan, cerobong hidrotermal, konvergensi lempeng, mineralisasi
INDEX-SATAL Expedition 2010 has revealed the phenomenon of hydrothermal activity in the western part of the Sangihe Waters in Kawio Barat Submarine Volcano with the peak which is located at 1860 m depths and the bottom at about 5400 m depths. A ROV (Remotely Operated Vehicle) "Little Hercules" dive in Kawio Barat was centered on the northwest side of the mountain began to sweep from the depths of 3000 m toward the top of 1860 m depths. The lithologic unit is characterized by the present of broken lavas covered with fine grey colored sediment whilist in the southeast side is composed of pillows lavas. In the southwest side, in which the deep valleys incise Kawio Barat, a clouds of smoke from the lower slopes are observed; finally at 1890 m depths a submarine hydrothermal activity is noted. This phenomenon represents the first submarine direct record made from the bottom of the Indonesian Waters. Those smokers phenomena are recorded along fissures, characterized by various colors of white, yellow to grey due to different chemical composition of hydrothermal fluids. Besides, the hot bubbles are also arised from the fissures. The other new discovery is the presence of hydrothermal chimney in the area of tectonically controlled by convergence plates. Rocks surrounding the hydrothermal vents are generally altered giving grey to white colors and the presence of dark yellow sulfur deposits. Mineralization may occur and accumulated in hydrothermal chimney and its surrounding to form brown-, grey-, and reddish- color deposits The latter are commonly found in inactive chimneys, indicated by the presence of dispersed brown and black color grains/chips of both sedimentary rocks or minerals as well.
Keywords: INDEX-SATAL 2010, hydrothermal activity, ROV, hydrothermal smokers, bubbles, hydrothermal chimney, plate convergence, mineralization
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PDF (Bahasa Indonesia)DOI: http://dx.doi.org/10.32693/jgk.11.1.2013.226