Abstract
The sedimentological study of thirteen sediment cores from the periplatform setting surrounding Pedro Bank (Northern Nicaragua Rise, Caribbean Sea) shows that during the last 300 ka turbidite deposition is controlled by at least four factors: (1) late Quaternary sea level fluctuations, (2) prolific fine-grained sediment production and export resulting in oversteepening of the upper slope environment, (3) the proximity to the bank margin, and (4) local slope and seafloor morphology. The most intriguing finding of this study is the paucity of turbidites, with only 101 turbidites in 13 cores in this tectonically active setting near the Caribbean plate boundary. Throughout the last 300 ka, the frequency of turbidite input during interglacial stages is three times higher than during glacial stages. Also it is obvious that changes in sea level influence the timing of turbidite deposition. This is especially evident during the transgressions resulting in rapid renewed bank-top flooding, subsequent neritic sediment overproduction, and offbank export. The flooding event during each transgression is usually recorded by the onset of turbidite deposition at various sites along several platform-to-basin transects in down- and upcurrent slope settings. Overall, however, more turbidites are deposited during the regressive rather than the transgressive phases in sea level, probably as a result of sediment reorganisation on the slope resulting in slope failure. Five cores show "highstand bundling" of calciturbidites, i.e. higher number of turbidites during highstands than during lowstands in sea level.
Original language | English |
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Pages (from-to) | 573-592 |
Number of pages | 20 |
Journal | International Journal of Earth Sciences |
Volume | 92 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 Sept 2003 |
Funding
Thirteen sediment cores were collected on the slopes and in the basins surrounding Pedro Bank (Northern Nicaragua Rise, eastern Caribbean Sea) during two US NSF-funded cruises on the R/V Cape Hatteras between 1988– 1992 (CH0288 and CH9204) and research cruise M35/1 funded by the German Science Foundation (DFG) on R/V Meteor (Fig. 1B, Table 1). Acknowledgements We thank the crew and scientific party of cruise M35/1 of the German research vessel R/V METEOR for their help in retrieving the cores. Financial support for this study was provided by the German Science Foundation (DFG, Du/129-11). The main financial support for A.W. Droxler was provided by several National Science Foundation research grants (OCE-8715922, -8900040, and 9116323). The authors thank Steffen Zamhöffer and Johanna Suhonen for their help with the laboratory work. We also thank journal reviewers Moyra Wilson (Durham) and Gregor Eberli (Miami) and topic editor Dan Bosence (London) for their constructive reviews.
Keywords
- Calciturbidites
- Carbonate platforms
- Highstand bundling
- Sea level fluctuations