000K  utf8
1100  $c2000
1500  eng
2050  urn:nbn:de:gbv:8-diss-3647
3000  Emmermann, Peter
4000  Mineralogie, Geochemie und Mikrofazies spätquartärer Periplattformsedimente$dKarbonatexportzyklen und sekundäre Prozesse  - Sanganeb Atoll und Abington Riff, Sudan, Mittleres Rotes Meer$hChristian-Albrechts-Universität zu Kiel  [Emmermann, Peter]
4000  Mineralogy, geochemistry and microfacies of late Quaternary periplatform sediments$dCarbonate export cycles and secondary processes - Sanganeb Atoll and Abington Reef, Sudan, Central Red Sea$hChristian-Albrechts-Universität zu Kiel  [Emmermann, Peter]
4030  Kiel$nChristian-Albrechts-Universität zu Kiel
4209  A set of sediment cores was obtained in the periplatform realm close to Sanganeb Atoll and Abington Reef, about 20 miles offshore the Sudanese coast in the central Red Sea. Microfacies, mineralogy and geochemistry of periplatform sediments were analysed to quantify glacial-interglacial variations in carbonate production and sediment export of the reefs in response to late Quaternary sealevel fluctuations. The present study showed that the periplatform sediments from the Sudanese shelf to great extend record variations in sediment export of the offshore reefs in tune with sealevel changes. This is clearly visible in the increased input of fine-grained, strontium- and aragonite-rich shallow-water derived sediment during the Holocene sealevel highstand, which is in good accordance with the highstand shedding model of carbonate systems. However, during the last interglacial sealevel highstands (marine isotope stage 5) this pattern is not clearly developed and generally no characteristic highstand bundling in the frequency of calciturbidites was observed in the Red Sea. Syn- and post-depositional processes play a significant role in the nearly isolated Red Sea basin with its unusual paleoceanographic and climatic conditions during the late Quaternary. Those processes to some extend changed the sealevel controlled sediment export signal. Of major importance is the submarine precipitation of aragonite and Mg-Calcite at the seafloor, which even led to the formation of a hard layer during marine isotope stage 2 when salinities of Red Sea surface- and bottom-waters rose over 50 ‰ during the sealevel lowstand. During high salinity phases of glacial sealevel lowstands biogenic carbonate production was drastically reduced because reefs and planktic organisms vanished nearly entirely from the Red Sea. Furthermore, glacial-interglacial changes in carbonate dissolution- and preservation at the seafloor occurred, partially in phase with monsoonal climate variations. Carbonate (aragonite) dissolution is generally increased during interglacials and a better preservation of this mineral was observed during humid phases (prevailing SW-monsoon) when stagnation of the basin led to oxygen depletion of the deeper water masses.
4950  https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-3647$xR$3Volltext$534
4961  https://macau.uni-kiel.de/receive/diss_mods_00000364
5051  550
5550  14C-AMS ages
5550  Abington Reef
5550  accumulation rates
5550  aragonite
5550  calcite
5550  carbon
5550  carbonate crust
5550  carbonate mineralogy
5550  carbonate platform
5550  carbonate production
5550  Carbonatplattform
5550  climate
5550  climate stratigraphy
5550  corals
5550  deep water circulation
5550  Diagenese
5550  dissolution
5550  Geochemie
5550  grainsize
5550  hard layers
5550  highstand
5550  highstand shedding
5550  high-strontium aragonite
5550  HMC
5550  Holocene
5550  Indian monsoon
5550  inorganic precipitation
5550  last interglacial
5550  late Quaternary
5550  LGM
5550  LMC
5550  lowstand
5550  Mg-calcite
5550  microfacies
5550  OMZ
5550  oxygen
5550  oxygen depletion
5550  periplatform sediment
5550  pointcounting
5550  preservation
5550  red algae
5550  Red Sea
5550  reef
5550  Rotes Meer
5550  salinities
5550  Sanganeb Atoll
5550  sapropel
5550  scleractinian
5550  sealevel changes
5550  Sedimentation
5550  sedimentation rates
5550  sediment export
5550  SPECMAP
5550  stable isotopes
5550  strontium
5550  Sudan
5550  U/Th-ages