| Autor: |
P. M. V. M. Gabriels, C. D. Green, B. P. Meier, R. McElroy |
| Rok vydání: |
1993 |
| Předmět: |
|
| Zdroj: |
Advances in Underwater Technology, Ocean Science and Offshore Engineering ISBN: 9789048142934 |
| DOI: |
10.1007/978-94-017-2473-9_18 |
| Popis: |
A suite of high quality, high resolution seabed survey data was used to investigate the flank of the Dira Reef, offshore Tanzania. The reef occurs on the upthrown side of an offshore normal fault related to the East African rift system. The fault is likely to have moved at a rate of approximately 2.5 mm.yr−1 for 16,000 years. This extension has opened up migration pathways which allowed biogenic gas to vent into the near-seabed soils sequences. The activity of the fault network also determined the nature and distribution of the shallow overburden sequences. They comprise a single fining-upwards depositional cycle compatible with formation during a relative sealevel rise. The Rufiji Delta drains the rift-flank area of the continental hinterland to the SW, and will eventually enroach the area and bury this sequence with coarser sediment. The relationships are therefore a small-scale geological analogy for features commonly occurring around ‘break-up unconformities’ buried beneath continental shelves in mixed carbonate/clastic settings. The complexities of the near seabed sediments, the presence of gas accumulations related to fault structures, and the restrictions imposed by the design of the available rig made for a challenging site survey operation. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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