22. TEXTURAL CHARACTERISTICS OF CENOZOIC PREGLACIAL AND GLACIAL
The Deep Sea Drilling Projects Site 270 was located to pass through the oldest part of a planed-off gently dipping sedimentary sequence in the south central Ross Sea, and successfully penetrated calc-silicate gneiss basement at 412 meters subbottom. The upper 20 meters (Unit 1) is largely sand-silt-...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.515.8237 http://www.deepseadrilling.org/28/volume/dsdp28_22.pdf |
| Summary: | The Deep Sea Drilling Projects Site 270 was located to pass through the oldest part of a planed-off gently dipping sedimentary sequence in the south central Ross Sea, and successfully penetrated calc-silicate gneiss basement at 412 meters subbottom. The upper 20 meters (Unit 1) is largely sand-silt-clay of Gauss age, with pebbles scattered throughout. It is capped with a 20-cm-thick veneer of diatom silty clay of Bruhnes age. Unit 2 comprises 364 meters of silty claystone with sparsely scattered pebbles, 16-25 m.y. in age on the basis of magnetic reversal stratigraphy. Units 3 and 4 are moderately sorted sandstones totalling 2 meters in thickness, and are in sharp contact with the glacial sediments above and a fossil soil developed on 26 meters of sedimentary breccia beneath. The breccia rests on basement gneiss. The older carbonaceous sandstone (Unit 4) is fine-grained and |
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