| Popis: |
The 1988 R/V Knorr Black Sea Oceanographic Expedition has provided a unique opportunity to study many aspects of the sediments of the Black Sea basin. Box cores collected during Leg 4 of the 1988 expedition revealed a wide range of uppermost Holocene sedimentary facies sampled over a broad region of the southern basin, including cores from two transects across the intersection of the water- column oxic/anoxic interface with the basin-margin substrate. The sediments collected during Leg 4 include: 1) muddy gray turbidite layers from the deep basin ranging in thickness from a few to several tens of centimeters and characterized by a predominance of fine grain sizes [fine silt—clay] and strong textural and chemical homogeneity, 2) an array of closely-spaced sediment types collected at basin-margin stations spanning the oxycline/substrate intersection which vary from a highly bioturbated, shell-rich oxic facies to dark-gray to black, water-rich, laminated muds from the anoxic zone and 3) coccolith-rich, microlaminated Unit 1 sediments of the abyssal Black Sea consisting of couplets of alternating white [coccolith-dominated] and dark-brown to black [siliciclastic-dominated] millimeter-scale laminae thought to reflect a strong depositional seasonality. These sediments are described in detail in terms of their physical and, to a lesser degree, chemical properties. |
