Eustatically controlled sedimentation recorded by Eocene strata of the James Ross Basin, Antarctica
Eustatically controlled sedimentation recorded by Eocene strata of the James Ross Basin, Antarctica
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南极洲詹姆斯罗斯盆地始新世地层记录的海平面上升控制沉积
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发表时间：
2006
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通讯作者：
S. Marenssi
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作者：
S. Marenssi
始新世La Meseta组是一个以不整合面为界的地层单元，记录了南极半岛东北部詹姆斯罗斯盆地构造活动减弱和火山活动间歇期的地质演化。该单元代表了一个复合下切谷，充满三角洲，河口和浅海沉积物，显示向陆地的相转移，表明沉积在整体海平面上升。六个不整合面为基础的内部单元（瓦莱德拉斯福卡斯，Acantilados，Campamento，Cucullaea I，Cucullaea II和Submeseta allomember）被解释为代表小规模的海退-海侵事件。地质学、古生物学和新的锶同位素年龄使基准面变化与二阶和三阶海平面升降波动相互关联。La Meseta组的基地与全球56 Ma的海平面低水位，其次是54.3和52.4 Ma之间的洪水的主要情节。CucullaeaI Allomestra的底部与著名的晚伊普雷期（49 Ma）低水位相对应，Submeseta Allomestra的底部与36 Ma低水位相对应。南极半岛北方始新世海平面波动与全球海平面变化曲线的相关性加强了海平面变化曲线全球同步性的概念。
Abstract The Eocene La Meseta Formation is an unconformity-bounded unit that records the geological evolution of the James Ross Basin, NE Antarctic Peninsula, during a period of decreasing tectonism and a lull in volcanic activity. This unit represents a composite incised valley, filled with deltaic, estuarine and shallow-marine deposits showing a landwards facies shift that indicates deposition during an overall sea-level rise. The six unconformity-based internal units (Valle de las Focas, Acantilados, Campamento, Cucullaea I, Cucullaea II and Submeseta allomembers) are interpreted to represent minor-scale regressive-transgressive events. Geological, palaeontological and new strontium isotopic ages allow the correlation of base-level changes with second- and third-order eustatic sea-level fluctuations. The base of the La Meseta Formation is correlated with a global 56 Ma lowstand in sea level followed by a main episode of flooding between 54.3 and 52.4 Ma. The base of the Cucullaea I Allomember is correlated with the well-known late Ypresian (49 Ma) lowstand, and the base of the Submeseta Allomember with the 36 Ma lowstand. Correlation of Eocene sea-level fluctuations in the northern Antarctic Peninsula with the global sea-level curve strengthens the concept of global syncroneity of the eustatic sea-level curve.