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摘要
The James Ross Sub-basin has one of the most complete sedimentary sequences deposited in the Southern Hemisphere. This work aims to characterize the sedimentary organic matter of 32 samples recovered from HL-1 (64 m) and HL-2 (59 m) sections, assigned to Hidden Lake Formation (Coniacian), thus to identify the paleoenvironmental changes. The Amorphous, Phytoclasts and Palynomorphs groups were identified. The sedimentary organic matter was grouped into amorphous material, opaque phytoclasts, non-opaque phytoclasts, continental palynomorphs and marine palynomorphs. The stratigraphic distribution of the groups revealed three intervals (I-III) for HL-1 section and four for HL-2 (A-D). The paleoenvironmental changes were supported based on facies association (AF-1-AF3), continental/marine ratio and principal components analysis. The two sections were correlated as follow: I/A, II/B and The Interval I/A is characterized by high values of woody material. The Interval II/B continues with high values of woody material; however, the highest peak of amorphous organic matter is recorded in HL-1 section, and the lowest abundance of non-opaque in the HL-2. In the III/C-D is recorded a conspicuous increase in marine elements in both sections. A fan-delta paleoenvironment is suggested for both sections. In section HL-1, a large amount of phytoclasts and volcanoclastic detritus suggests more proximal position in the sedimentary body. In the HL-2 section, a large amount of marine elements suggests normal marine removed from active terrigenous inputs.
- 出版日期2017-4
