Eustatic sea-level fluctuations along the Indian Ocean coast of Mozambique during the last 6600 years
Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
A 3 m-long sediment core from Macassa Bay, Mozambique, was collected in order to trace past sea-level changes. Diatom stratigraphy, organic carbon content and mineral magnetic parameters were used as proxies in this study combined with AMS 14C dating. The core covers the last c. 6600 yrs, i.e. from the mid-Holocene marine transgression onwards. Five zones were established based on the diatom assemblages and the organic carbon content. At c. 6600 cal. yrs BP, sea level shows a rising trend culminating c. 6500 cal. yrs BP. This period was followed by a series of fluctuations. A lagoon formed during a period of sea regression between c. 6300 and 4500 cal. yrs BP. A second marine transgression was observed between 4500 and 1000 cal. yrs BP. The sea reached its present level after 1000 cal. yrs BP. The inferred variations in mean sea level, mainly based on the stratigraphic occurrence of Pseudopodosira sp., were compared with other studies and correspond relatively well with results from coastal areas in Namibia and Sri Lanka.
The reasons behind a mass occurrence of the diatom taxa Pseudopodosira sp. remain unclear. Two theories are presented in the study; either the genera grew in the Indian Ocean during the Holocene, or it represents reworking from Tertiary bedrock in the vicinity. Pseudopodosira sp. seems, however, to be a relevant sea-level indicator as it is in either case transported by the sea to the sampling site.
Place, publisher, year, edition, pages
2009. , 46 p.
sea-level changes, Mozambique, Holocene, diatoms
IdentifiersURN: urn:nbn:se:su:diva-36815OAI: oai:DiVA.org:su-36815DiVA: diva2:290395
UppsokLife Earth Science
Risberg, JanHolmgren, Karin