Cretaceous-Palaeogene sub-basaltic and intrabasaltic sediments of the Kangerdlugssuaq area, Central East Greenland
Summary Cretaceous-Palaeogene sediments of the Kangerdlugssuaq area on the continental margin of Central East Greenland were deposited in an embayment of an extensive pre-NE Atlantic shelf sea. Pre-Sparnacian sediments are thin (150 m), incomplete and of siliciclastic type, formed in shallow marine...
| Published in: | Geological Magazine |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
1981
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1017/s0016756800032210 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756800032210 |
| Summary: | Summary Cretaceous-Palaeogene sediments of the Kangerdlugssuaq area on the continental margin of Central East Greenland were deposited in an embayment of an extensive pre-NE Atlantic shelf sea. Pre-Sparnacian sediments are thin (150 m), incomplete and of siliciclastic type, formed in shallow marine waters. Sparnacian times saw the onset of vigorous basaltic vulcanicity, marking the initial rifting episode between Greenland and Eurasia. Uplift immediately prior to the vulcanicity is evidenced by an unconformity at the base of the Sparnacian, above which basement-derived arkosic sandstones and conglomerates are followed by about 1.5 km of coarse volcaniclastics, basaltic flows of dominantly picritic composition, pro-grading hyaloclastite wedges and thin siltstones with abundant organic detritus. Very rapid subsidence accompanied this early phase of vulcanicity, maintaining the top of the pile close to sea level and allowing the deposition of a further kilometre of waterlain tuffs in the embayment. Sedimentation extended northwards and eastwards on to basement rocks at this period, with the formation of a non-marine sequence which includes coals. The overlying plateau tholeiites overlap the earlier volcanics; their depositional area was extremely extensive along the East Greenland margin and bears no relationship to the Kangerdlugssuaq sedimentary embayment, although their thickest development, 4 km or more, was attained in that region. Eruption rate of the pile exceeded subsidence for a period and it is dominantly subaerial. This sequence of events is compared with the similar history of sedimentation and basaltic vulcanicity on the west coast of Greenland, and it is inferred that just as the East Greenland sequence records the initiation of spreading between Greenland and Rockall-Faeroe at anomaly 24−25 time, so that of West Greenland marks the propagation of the Labrador Sea spreading axis through the Davis Strait into Baffin Bay at anomaly 26−27 time. |
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