Latest Quaternary palaeoceanographic change in the eastern North Atlantic based upon a dinoflagellate cyst event ecostratigraphy
نویسندگان
چکیده
The analyses of dinoflagellate cyst records, from the latest Quaternary sediments recovered from DSDP Core 610A taken on the Feni Ridge in the southern Rockall Trough, and part of core MD01-2461 on the continental margin of the Porcupine Seabight in the eastern North Atlantic Ocean, has provided evidence for significant oceanographic change encompassing the Last Glacial Maximum (LGM) and part of the Holocene. This together with other published records has led to a regional evaluation of oceanographic change in the eastern North Atlantic over the past 68 ka, based upon a distinctive dinoflagellate event ecostratigraphy. These changes reflect changes in the surface waters of the North Atlantic Current (NAC), and perhaps the deeper thermohaline Atlantic Meridional Overturning Circulation (AMOC), driving fundamental regime changes within the phytoplanktonic communities. Three distinctive dinoflagellate cyst associations based upon both factor and cluster analyses have been recognised. Associations characterised by Bitectatodinium tepikiense (between 61.1 ± 6.2 to 13.4 ± 1.1 ka BP), Nematosphaeropsis labyrinthus (between 10.5 ± 0.3 and 11.45 ± 0.8 ka. BP), and the cyst of Protoceratium reticulatum (between 8.5 ± 0.9 and 5.2 ± 1.3 ka. BP) indicate major change within the eastern North Atlantic oceanography. The transitions between these changes occur over a relatively short time span (c.1.5 ka), given our sampling resolution, and have the potential to be incorporated into an event stratigraphy through the latest Quaternary as recommended by the INTIMATE (INTegrating Ice core, MArine and TErrestrial records) group. The inclusion of a dinoflagellate cyst event stratigraphy would highlight changes within the phytoplankton of the North Atlantic Ocean as a fully glacial world changed to our present interglacial.
منابع مشابه
Application of artificial neural networks (ANN) to high-latitude dinocyst assemblages for the reconstruction of past sea-surface conditions in Arctic and sub-Arctic seas
The artificial neural network (ANN) method was applied to dinoflagellate cyst (dinocyst) assemblages to estimate palaeoceanographical conditions. The ANN method was adapted to three distinct data bases covering the northern North Atlantic (N = 371), plus the Arctic seas (N = 540) and the Bering Sea (N = 646). The relative abundance of 23 dinocyst taxa was calibrated against hydrographic variabl...
متن کاملDistribution and geochemical variations among paleogene volcanic rocks from the north-central Lut block, eastern Iran
The Lut block in eastern Iran is a micro-continental block within the convergent orogen between the Arabian, Eurasian and Indian plates. Large areas of the north-central, eastern, and western Lut block are covered by volcanic rocks of Paleogene, Neogene and Quaternary age. Peak volcanic activity took place in the north-central part of the Lut block during the Eocene, and then dramatically decr...
متن کاملReview of age, Rb-Sr geochemistry and petrogenesis of Jurassic to Quaternary igneous rocks in Lut Block, Eastern Iran
The Lut Block (Eastern Iran) extends over 900 km in a north-south direction and is only 200 km wide in an east-west direction. It is confined by the Nayband fault and Shotori Range on the west. The eastern edge is bordered by the Sistan suture zone and Nehbandan Fault. The northern termination of Lut Block is the depression of Kavir-e-Namak and the Great Kavir Fault. The Makran arc, including ...
متن کاملHolocene variations of sea-surface conditions in the southeastern Barents Sea, reconstructed from dinoflagellate cyst assemblages
Palynomorphs were analysed in two sediment cores from the southeastern Barents Sea representing the past 8.3 and 4.4 kyr. High dinocyst contents and species diversity enabled the application of the best analogue method to quantitatively reconstruct sea-surface salinities, temperatures and ice cover using 677 modern reference sites from the North Atlantic and Arctic seas, including new data from...
متن کاملImplications of the Permanent El Niño Teleconnection "Blueprint" for Past Global and North American Hydroclimatology
Substantial evidence exists for wetter-thanmodern continental conditions in North America during the pre-Quaternary warm climate intervals. This is in apparent conflict with the robust global prediction for future climate change of a northward expansion of the subtropical dry zones that should drive aridification of many semiarid regions. Indeed, areas of expected future aridification include m...
متن کامل