The Late Precambrian Paleo-Ocean Evolution of the Southeast Yangtze Continental Margin: REE Record

Yi Haisheng; Peng Jun; Xia Wenjie

We report REE (rare earth elements) data of 19 samples from Upper Sinian - Lower Cambrian chens by neutron activation analysis. The REE patterns with respect to an average shale show complicate changes and are preliminarily classified into different types, including "platform-type", "Red Sea-type", "seawater-type"and two distinctive types. The Ce depletion in the section exhibits a progressive increase from the lower to upper beds. The Ce anomaly,as an indicator of redox conditions, reveals that paleo-ocean bottom seawater in this area was anoxic during Late Precambrian and an oxidizing environment occurred in Early Cambrian.The occurrence of positive Eu anomaly may indicate submarine hydrothermal deposition.

Chengdu College of Geology, Chengdu 610059

Received Date: 1994-03-12

Publish Date: 1995-12-10

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Abstract: We report REE (rare earth elements) data of 19 samples from Upper Sinian - Lower Cambrian chens by neutron activation analysis. The REE patterns with respect to an average shale show complicate changes and are preliminarily classified into different types, including "platform-type", "Red Sea-type", "seawater-type"and two distinctive types. The Ce depletion in the section exhibits a progressive increase from the lower to upper beds. The Ce anomaly,as an indicator of redox conditions, reveals that paleo-ocean bottom seawater in this area was anoxic during Late Precambrian and an oxidizing environment occurred in Early Cambrian.The occurrence of positive Eu anomaly may indicate submarine hydrothermal deposition.

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The Late Precambrian Paleo-Ocean Evolution of the Southeast Yangtze Continental Margin: REE Record

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