/* DATA DESCRIPTION: Citation: Seeberg-Elverfeldt, Ismene A; Lange, Carina Beatriz; Arz, Helge Wolfgang; Pätzold, Jürgen; Pike, Jennifer (2004): Smear slide analysis of sediment core GeoB5836-2. PANGAEA, https://doi.org/10.1594/PANGAEA.708063, Supplement to: Seeberg-Elverfeldt, IA et al. (2004): The significance of diatoms in the formation of laminated sediments of the Shaban Deep, Northern Red Sea. Marine Geology, 209(1-4), 279-301, https://doi.org/10.1016/j.margeo.2004.05.019 Abstract: Laminated sediments spanning the last 20,000 years (though not continuously) in the Shaban Deep, a brine-filled basin in the northern Red Sea, were analyzed microscopically and with backscattered electron imagery in order to determine laminae composition with emphasis on the diatomaceous component. Based on this detailed study, we present schematic models to propose paleoflux scenarios for laminae formation at different time-slices. The investigated core (GeoB 5836-2; 26°12.61'N, 35°21.56'E; water depth 1475 m) shows light and dark alternating laminae that are easily distinguishable in the mid-Holocene and at the end of the deglaciation (13-15 ka) period. Light layers are mainly composed of coccoliths, terrigenous material and diatom fragments, while dark layers consist almost exclusively of diatom frustules (monospecific or mixed assemblages). The regularity in the occurrence of coccolith/diatom couplets points to an annual deposition cycle where contrasting seasons and associated plankton blooms are represented (diatoms-fall/winter deposition, coccoliths-summer signal). We propose that, for the past ~15,000 years, the laminations represent two-season annual varves. Strong dissolution of carbonate, with the concomitant loss of the coccolith-rich layer in sediments older than 15 ka, prevents us from presenting a schematic model of annual deposition. However, the diatomaceous component reveals a marked switch in species composition between Last Glacial Maximum (LGM) sediments (dominated by Chaetoceros resting spores) and sediments somewhat younger (18-19 ka; dominated by Rhizosolenia). We propose that different diatom assemblages reflect changing conditions in stratification in the northern Red Sea: Strong stratification conditions, such as during two meltwater pulses at 14.5 and 11.4 ka, are reflected in the sediment by Rhizosolenia layers, while Chaetoceros-dominated assemblages represent deep convection conditions. Related to: Seeberg-Elverfeldt, Ismene A (2004): Laminated diatomaceous sediments of the Red Sea, their composition and significance as recorders of abrupt changes in productivity and circulation during the Late Quaternary. PhD Thesis, Elektronische Dissertationen an der Staats- und Universitätsbibliothek Bremen, Germany, urn:nbn:de:gbv:46-diss000009977 Project(s): Center for Marine Environmental Sciences (MARUM) (URI: https://www.marum.de/en/) Coverage: LATITUDE: 26.210200 * LONGITUDE: 35.359300 DATE/TIME START: 1999-03-31T02:09:00 * DATE/TIME END: 1999-03-31T02:09:00 MINIMUM DEPTH, sediment/rock: 0.010 m * MAXIMUM DEPTH, sediment/rock: 0.518 m Event(s): GeoB5836-2 * LATITUDE: 26.210200 * LONGITUDE: 35.359300 * DATE/TIME: 1999-03-31T02:09:00 * ELEVATION: -1475.0 m * Recovery: 8.03 m * LOCATION: Northern Red Sea * CAMPAIGN: M44/3 (URI: https://doi.org/10.2312/cr_m44) * BASIS: Meteor (1986) (URI: https://en.wikipedia.org/wiki/RV_Meteor_(1986)) * METHOD/DEVICE: Gravity corer (Kiel type) (SL) Parameter(s): DEPTH, sediment/rock [m] (Depth sed) * GEOCODE Color description (Color desc) * PI: Seeberg-Elverfeldt, Ismene A (Ismene.Seeberg-elverfeldt@dfg.de) Texture (Texture) * PI: Seeberg-Elverfeldt, Ismene A (Ismene.Seeberg-elverfeldt@dfg.de) Comment (Comment) * PI: Seeberg-Elverfeldt, Ismene A (Ismene.Seeberg-elverfeldt@dfg.de) License: Creative Commons Attribution 3.0 Unported (CC-BY-3.0) (URI: https://creativecommons.org/licenses/by/3.0/) Size: 50 data points */ Depth sed [m] Color desc Texture Comment 0.010 olive soupy Abundant coccoliths, broken pieces of diatoms (Azpeitia, Thalassionema, Thalassiosira)and silicoflagellates; calcite grains 0.070 olive Common coccoliths, diatoms (Azpeitia, Coscinodiscus, Thalassiosira) and silicoflagellates present 0.090 olive Common coccoliths, diatoms and silicoflagellates; also fragile species present few Azpeitia; mainly Thalassiosira, some Rhizosolenia 0.120 olive Common coccoliths, diatoms and silicoflagellates present 0.140 olive little material; assemblage as before; less diatoms 0.150 olive Common coccoliths, diatoms and silicoflagellates present fewer diatoms than in 17 cm and 20 cm 0.170 olive Common coccoliths, diatoms well preserved ( Chaetoceros veg. cells, Hemiaulus) 0.200 olive Frequent coccoliths, diatoms and silicoflagellates present bad preservation; few Rhizosolenia 0.230 olive laminated Frequent coccoliths, diatoms (N. bicapitata; few Azpeitia and Coscinodiscus) and silicoflagellates present, weakly silicified species; Rhizosolenia 0.235 light laminated Common coccoliths, diatoms and silicoflagellates present, bad preservation (few N. bicapitata; few Azpeitia) 0.240 dark laminated Frequent coccoliths, frequent diatoms, silicoflagellates; good preservation 0.253 light laminated Frequent coccoliths, diatoms and silicoflagellates; good preservation 0.256 dark laminated Frequent coccoliths, diatoms (Chaetoceros setae, Rhizosolenia), silicoflagellates, radiolarians; better preseration than in light lamina 0.338 light laminated Frequent coccoliths, few diatoms 0.390 dark laminated Frequent coccoliths, more diatoms than in 42.7 cm, (no Azpeitia ); very good preservation 0.427 light laminated Common coccoliths, less diatoms (no Azpeitia ) 0.440 dark laminated Few coccoliths, few diatoms (no Azpeitia ); bad preservation 0.490 dark laminated Few coccoliths, few diatoms (some Azpeitia); bad preservation 0.518 dark-olive laminated Frequent coccoliths, few diatoms; bad preservation