• 자원환경지질
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• 제37권5호
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• pp.437-457
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• 2004

인도네시아 중부 칼리만탄 쿠알라쿠룬 지역의 지질은 하부로부터 석탄-페름기의 피노변성암류, 백악기 세파욱심성암류, 에오세말기의 탄중층과 올리고세의 말라산화산암류로 구성되며, 올리고세-마이오세초기의 신탕관입암류가 상기한 모든 지층들을 관입하고 있다. 퇴적층인 탄중층은 전체적으로 북쪽으로부터 남쪽으로 발달하는 고수류계를 유지하는 삼각주 환경과 천해 해저 환경에서 퇴적되었다. 고생대 후기의 변성퇴적암류가 퇴적된 이후부터 발생한 4회의 변형작용이 인지된다. D1 변형작용은 광역변성작용을 수반한 변성암류의 습곡작용 및 S1 편리구조 형성으로 특징 지워진다. D2 변형작용은 백악기 화강암질암 내에 발생한 연성전단작용이며, D3 변형작용은 북동 내지 동북동 방향의 축을 갖는 습곡작용 및 이에 수반된 S2 파랑벽개의 형성으로 정의된다. D4 변형작용은 제3기 동안 남-북 방향의 압축응력하에서 발생한 단층작용으로서, 북동 방향의 좌수향 주향이동단층, 북서 방향의 우수향 주향이동단층, 남-북 내지 북북동 방향의 정단층 등이 형성 되었다. 이 단층작용은 제3기 지층의 퇴적과 분포에 영향을 끼친 것으로 해석된다.

• Ocean and Polar Research
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• 제39권2호
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• pp.85-106
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• 2017

The Lago Sofia conglomerate in southern Chile is a deep-marine gravelly deposit, which is hundreds of meters thick and kilometers wide and extends laterally for more than 100 km, filling the foredeep trough of the Cretaceous Magallanes Basin. For understanding the depositional processes and environments of this gigantic deep-sea conglomerate, detailed analyses on sedimentary facies, architecture and paleoflow patterns were carried out, highlighting the differences between the northern (Lago Pehoe and Lago Goic areas) and southern (Lago Sofia area) parts of the study area. The conglomerate bodies in the northern part occur as relatively thin (< 100 m thick), multiple units intervened by thick mudstone-dominated sequences. They show paleoflows toward ENE and S to SW, displaying a converging drainage pattern. In the southern part, the conglomerate bodies are vertically interconnected and form a thick (> 400 m thick) conglomerate sequence with rare intervening fine-grained deposits. Paleoflows are toward SW. The north-to-south variations are also distinct in sedimentary facies. The conglomerate bodies in the southern part are mainly composed of clast-supported conglomerate with sandy matrix, which is interpreted to be deposited from highly concentrated bedload layers under turbidity currents. Those in the northern part are dominated by matrix- to clast-supported conglomerate with muddy matrix, which is interpreted as the products of composite mass flows comprising a turbidity current, a gravelly hyperconcentrated flow and a mud-rich debris flow. All these characteristics suggest that the Lago Sofia conglomerate was formed in centripetally converging submarine channels, not in centrifugally diverging channels of submarine fans. The tributaries in the north were dominated by mass flows, probably affected by channel-bank failures or basin-marginal slope instability processes. In contrast, the trunk channel in the south was mostly filled by tractive processes, which resulted in the vertical and lateral accretion of gravel bars, deposition of gravel dunes and filling of scours and channels, similar to deposits of terrestrial gravel-bed rivers. The trunk channel developed along the axis of foredeep trough and its confinement within the trough is probably responsible for the thick, interconnected channel fills. The large-scale architecture of the trunk-channel fills shows an eastward offset stacking pattern, suggesting that the channel migrated eastwards most likely due to the uplift of the Andean Cordillera.