Terrestrial Source to Deep-Sea sedimentary Environments: Insights from the West Coast of NW Africa (Morocco)
Abstract
Except few lake records from the Atlas Mountains, most Quaternary paleoclimate and paleoenvironment studies have been generated from marine sediment archives that record adjacent terrestrial signals. Although, these marine records have greatly improved the understanding of the regional climate system, the interpretation of terrigenous climatic signals in marine sediments still requires a thorough understanding of initial source regions of different components as well as of their transport and their deposition. This is particularly important in southern Morocco that represents one of the world's most important upwelling systems with high surface ocean productivity influenced by large amounts of Saharan dust deposits delivering nutrients into the Ocean. To investigate the source of various terrigenous sediment fractions in NW Africa, we have performed an extensive comparison between terrestrial material (pollen, plant lipids, as well as bulk inorganic geochemical composition) from potential source regions with strong proximity to river mouths and the adjacent coastal and continental shelf sediments offshore Southern Morocco. Onshore, the proxy-indicators reflect large diversity in sampling locations and associated environments (riverbank sediments, flood deposits and soils) with overall trends reflecting significant environmental gradients along a North to South transect. We note a general comparability of the investigated parameters between the continental and marine sediments regardless of their specific differences in transport and depositional processes along the NW African coast. Particularly, the distribution pattern of the endemic Argania spinosa in marine surface sediments corresponds well with its modern terrestrial distribution in southwestern Morocco. Although aeolian transport in marine sediments off NW Africa is the main transport agent, another evident source of terrigenous sediments is the fluvial supply from several rivers draining from the Atlas Mountain (e.g., Souss and Tensift Rivers). This study provides a „baseline" for the calibration and comparison between terrestrial and oceanic processes that are important for the attribution of temporal variations of composition changes in the common proxy indicators used in most paleorecords of NW Africa.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMPP13F1409K
- Keywords:
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- 4901 Abrupt/rapid climate change;
- PALEOCEANOGRAPHYDE: 4926 Glacial;
- PALEOCEANOGRAPHYDE: 4928 Global climate models;
- PALEOCEANOGRAPHYDE: 4999 General or miscellaneous;
- PALEOCEANOGRAPHY