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| Titel |
Recent benthic foraminifera and sedimentary facies distribution of the Abu Dhabi (United Arab Emirates) coastline |
| VerfasserIn |
Flavia Fiorini, Stephen W. Lokier |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090608
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| Publikation (Nr.) |
 EGU/EGU2014-4865.pdf |
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| Zusammenfassung |
| The distribution of benthic foraminifera and sedimentary facies from Recent coastline
environments adjacent to the coastline of Abu Dhabi (UAE) was studied in detail with the
aim to: 1) provide reliable analogs for understanding and interpreting the depositional
environment of ancient shallow-marine sediments from the UAE; 2) assess any
modifications in the distribution of benthic environments and sedimentary facies in an area
affected by significant anthropogenic activities – particular construction and land
reclamation.
A total of 100 sea-floor sediment samples were collected in different shallow-marine
sedimentary environments (nearshore shelf, beach-front, channels, ooid shoals, lagoon and
mangals) close to the coastline of Abu Dhabi Island. Where possible, we revisited
the sampling sites used in several studies conducted in the middle of last century
(prior to any significant anthropogenic activities) to assess temporal changes in
Recent benthic foraminifera and sedimentary facies distribution during the last 50
years.
Five foraminiferal assemblages were recognized in the studied area. Species with a
porcellaneous test mainly belonging to the genera Quinqueloculina, Triloculina,
Spiroloculina, Sigmoilinita are common in all studied areas. Larger benthic foraminifera
Peneroplis and Spirolina are particularly abundant in samples collected on seaweed. Hyaline
foraminifera mostly belonging to the genera Elphidium, Ammonia, Bolivina and Rosalina are
also common together with Miliolidae in the nearshore shelf and beach front. Agglutinated
foraminifera (Clavulina, Textularia, Ammobaculites and Reophax) are present in low
percentages. The species belonging to the genera Ammobaculites and Reophax are present
only in the finest grain samples particularly in lagoons and mangal environments and have not
been reported previously in the studied area. The majority of the ooid shoal sediments, the
coarser sediments of the beach-front and samples collected in dredged channels do not
contain living foraminifera and the dead assemblage is mostly composed of a few specimens
of coarse-sized Miliolidae with fragmented or abraded tests, probably transported from
nearby environments.
While the shallow-water settings of the Abu Dhabi coastline continue to be areas of active
carbonate sedimentation, there have been significant changes in facies distributions over the
last 50 years. In particular:
• The opportunistic genera Ammonia and Elphidium have become more abundant. Reophax
and Ammobaculites are reported in the area for the first time.
• With anthropogenic activities some environments, such as inner lagoons, are lost whilst
other areas show resilience to anthropogenic activities with little change in sedimentary facies
distribution and foraminiferal assemblage.
• No living foraminifera are found in dredged channels.
The detailed analysis of these changes in foraminifera distribution and sedimentary facies
allows us to further our understanding of the effects of anthropogenic activities on
shallow-marine environments. By so doing, we are better able to distinguish between
those changes that result from anthropogenic activities and those that are a result of
naturally-occurring environmental perturbations. |
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