Pollen and non-pollen palynomorph records of the Holocene part of the composite sediment core TMD from lake Tso Moriri (NW India) and of modern surface samples from the Tso Moriri region

The high-altitude lake Tso Moriri (32°55'46'' N, 78°19'24'' E; 4522 m a.s.l.) is situated at the margin of the ISM and westerly influences in the Trans-Himalayan region of Ladakh. Human settlements are rare and domestic and wild animals are concentrating at the alpine meadows. A set of modern surface samples and fossil pollen from deep-water TMD core was evaluated with a focus on indicator types revealing human impact, grazing activities and lake system development during the last ca. 12 cal ka BP. Furthermore, the non-pollen palynomorph (NPP) record, comprising remains of limnic algae and invertebrates as well as fungal spores and charred plant tissue fragments, were examined in order to attest palaeolimnic phases and human impact, respectively. Changes in the early and middle Holocene limnic environment are mainly influenced by regional climatic conditions and glacier-fed meltwater flow in the catchment area. The NPP record indicates low lake productivity with high influx of freshwater between ca. 11.5 and 4.5 cal ka BP which is in agreement with the regional monsoon dynamics and published climate reconstructions. Geomorphologic observations suggest that during this period of enhanced precipitation the lake had a regular outflow and contributed large amounts of water to the Sutlej River, the lower reaches of which were integral part of the Indus Civilization area. The inferred minimum fresh water input and maximum lake productivity between ca. 4.5-1.8 cal ka BP coincides with the reconstruction of greatest aridity and glaciation in the Korzong valley resulting in significantly reduced or even ceased outflow. We suggest that lowered lake levels and river discharge on a larger regional scale may have caused irrigation problems and harvest losses in the Indus valley and lowlands occupied by sedentary agricultural communities. This scenario, in turn, supports the theory that, Mature Harappan urbanism (ca. 4.5-3.9 cal ka BP) emerged in order to facilitate storage, protection, administration, and redistribution of crop yields and secondly, the eventual collapse of the Harappan Culture (ca. 3.5-3 cal ka BP) was promoted by prolonged aridity. There is no clear evidence for human impact around Tso Moriri prior to ca. 3.7 cal ka BP, with a more distinct record since ca. 2.7 cal ka BP. This suggests that the sedimentary record from Tso Moriri primarily archives the regional climate history.

Composition of suspended matter and bottom sediments from the Atlantic Ocean and its seas

The book summarizes data on distribution and composition of sedimentary material suspended in waters of the Atlantic Ocean and its seas. Results of observations of Soviet and foreign expeditions are given. Distribution of suspended matter in sections across the ocean, as well as in the most studied seas are shown. New data on grain size, mineral and chemical composition of suspended matter are published. Summary of history of investigation of bottom sediments from the Atlantic Ocean from the first scientific cruises to the present is done. A brief description of sediment types in the ocean and a detailed description of Mediterranean Sea sediments are given.

(Table 1) Coarse-fraction (0.1 to 0.05 mm) mineralogy at DSDP Leg 55 Holes

This chapter was previously intended to trace volcanic episodes through the Neogene and Pleistocene geological history recorded in the sedimentary sections drilled on the Emperor seamounts. Drilling disturbance, poor core recovery, and incomplete stratigraphic sections recovered from the seamounts have frustrated that plan, however. Moreover, the Leg 55 sedimentologists found in their smear-slide studies that transported island-arc tephra is scarce in the sediments, if present at all. So we have restricted our objective to description of the volcaniclastic admixture in sediments, as determined by mineralogical and geochemical data. We studied geochemistry of bulk samples (see Murdmaa et al., 1980), coarse-fraction mineralogy, and additional smear slides. The results obtained, however, do not tell much more about the volcaniclastic matter than did shipboard core descriptions.

Layer-by-layer correlation of ODP Leg 117 sites

One hundred thirty-one marker horizons relating to the distinct and traceable layers were described for the Owen Ridge and Oman Margin sites. The correlations incorporated the calculations of true depth, corrected for coring disturbance and gas expansion. Intersite correlation of marker horizons has been improved based on color density data, measured with video densitometer, and oxygen isotope stratigraphic data. Distinct hiatuses were detected by the intersite correlation of the marker horizons in the Owen Ridge. The hiatuses are related to submarine slides induced by increasing gravitational instability for the accumulation of the pelagic sediments on the top of the Owen Ridge. The large amount of sediment supply with variable lithofacies during the glacial stages is represented by layer-bylayer correlation in the Oman Margin. The color density patterns with glacial-interglacial cycles are controlled by the balance of organic carbon content, increasing in the interglacial stages with strong upwelling induced by the southwest monsoon, and flux of terrigenous matter, increasing in the glacial stages. The present distinct climatic cycle relating to the southwest monsoon has been developed since Stage 8, 250 ka. The large amount of sediment supply in the glacial stages can be assumed as fluvial in origin from the humid Arabian Peninsula, relating to the weakened Tropical Easterly Jet, which is induced by the counter-current of the southwest monsoon and maintains the present arid climate in the north Africa and Arabian Peninsula.

Abundance estimates of diatoms in ODP Leg 207 sediments

Twenty-eight core catcher samples were provided to the author by the shipboard party for evaluation of fossil diatoms. Samples are from Ocean Drilling Program Leg 207 Holes 1257A, 1257B, 1257C, and 1258A. The samples range from 50 to 112 meters below the seafloor (mbsf) at Site 1257 and from ~22 to 60 mbsf at Site 1258. At Site 1257, samples range in age from middle Eocene (foraminifer Zone P14-13) to late Paleocene (mid-foraminifer Zone P4). At Site 1258, the samples range from middle Eocene (foraminifer Zone P11) to early Eocene (foraminifer Zone P5) according to the preliminary biostratigraphic reports (Erbacher, Mosher, Malone, et al., 2004, doi:10.2973/odp.proc.ir.207.2004). All samples were processed at Florida State University Antarctic Research Facility. Treatment included acidization and sieving through stacked 38- and 63-µm sieves. Strew slides were made from each fraction and the catcher pan. A Zeiss Photoscope II microscope was used for examination of the prepared slides. Samples from Holes 1257A, 1257B, and 1257C showed that most of the samples are barren of siliceous microfossils. Only a few radiolarians and fragments of radiolarians were observed.