Delineation of the Subsurface Structures in the Central Sumatra Basin (Indonesia) through Bouguer Gravity Data

Year 2024, , 537 - 542, 23.12.2024

Ezgi Erbek-kıran , Fahmi Ainun Nadjib

https://doi.org/10.19113/sdufenbed.1539802

Abstract

This study presents the delineation of the boundaries of the subsurface structures located in the eastern part of the central Sumatra basin using Bouguer gravity data. The existence of the high gravity anomalies in the eastern part displayed in this sedimentary basin takes attention. Therefore, investigation of the reason for these high anomalies is required for the region. To this end, gravity anomalies have been processed by advanced potential field methods such as the power spectrum analysis method and tilt method. The average depths of the deep and shallow causative sources have been calculated as 23.71 km and 1.61 km, respectively. Furthermore, the boundaries of the causative sources have been determined utilizing the tilt method. The tilt map has shown that the reason for these high anomalies could be the bedrock composed of high-density material rising upwards, considering the tectonic background of the region. This study has determined that this high structure is in the form of a triple structure and that its upper depths are approximately 5.8 km, 11.30 km, and 12.8 km from north to south, respectively. As a result, it could be said that such sources with deep roots could be prospective for hydrocarbon maturation.

Keywords

Sumatra Island, Bouguer gravity anomaly, Tilt, Half-Distance, Subduction zone

Bouguer Gravite Verileriyle Orta Sumatra Havzasındaki (Endonezya) Yeraltı Yapılarının Belirlenmesi

Abstract

Özet: Bu çalışma, Bouguer gravite verilerini kullanarak Sumatra merkez havzasının doğu kısmında yer alan yeraltı yapılarının sınırlarının belirlenmesini sunmaktadır. Bu sedimanter havzanın doğu kesiminde yüksek gravite anomalilerinin varlığı dikkat çekmektedir. Bu nedenle bölge için bu yüksek anomalilerin nedeninin araştırılması gerekmektedir. Bu amaçla gravite anomalileri, güç spektrumu analiz yöntemi ve tilt yöntemi gibi ileri potansiyel alan yöntemleriyle işlenmiştir. Derin ve sığ nedensel kaynakların ortalama derinlikleri sırasıyla 23,71 km ve 1,61 km olarak hesaplanmıştır. Ayrıca tilt yöntemi kullanılarak anomaliye neden olan yapıların sınırları da belirlenmiştir. Tilt haritası, bölgenin tektonik arka planı dikkate alındığında bu yüksek anomalilerin nedeninin yukarıya doğru yükselen yüksek yoğunluklu malzemeden oluşan ana kaya olabileceğini göstermiştir. Bu yüksek yapının üçlü bir yapı biçiminde olduğu ve üst derinliklerinin kuzeyden güneye sırasıyla yaklaşık 5,8 km, 11,30 km ve 12,8 km olduğu bu çalışma ile belirlenmiştir. Sonuç olarak kökleri derin olan bu tür kaynakların hidrokarbon olgunlaşması açısından umut verici olabileceği söylenebilir.

Keywords

Sumatra adası, Bouguer gravite anomalisi, Tilt, Yarı-mesafe, Dalma-batma zonu

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