535 resultados para Triple bottom
Resumo:
This paper is devoted to studies of clay minerals from two cores collected in the northern and central regions of the St. Anna Trough, the largest trough of the Kara Sea. Upper Quaternary glacial, glaciomarine, and marine deposits are characterized by various contents of kaolinite, chlorite, illite, and smectite. It is established that, from older to younger deposits, amounts of kaolinite and chlorite generally decrease, while those of illite and smectite, on the contrary, increase. A joint analysis of distributions of clay and heavy minerals over the section allowed us to refine position of sources for terrigenous matter and their temporal variability. It is shown changes in sources of supply were directly related to climate changes that occurred when passing from glacial to marine sedimentation environments.
Resumo:
Analysis of composition and distribution of benthic foraminifers in six samples of bottom sediments obtained in the southeast Kandalaksha Bay of the White Sea at water depths of 20 to 155 m revealed their dependence on lithology and different hydrological characteristics. It is shown that living foraminifers populating relatively shallow areas of the bay (20-60 m), which are bathed by seasonally warmed intermediate water with temperature 0.7-1.5°C and salinity 26 per mil, are characterized by high abundance (250-750 specimens/10 ccm of wet sediment) and prevalence of agglutinated species (Eggerella advena, Recurvoides turbinatus, and others). Deeper (155 m) where cold and relatively saline deep water occurs (-1.4°C, 29.5 per mil), abundance is an order lower (30 specimens/10 ccm) and is dominated by calcareous taxa Cassidulina reniforme, an Arctic cold resistant species.
Resumo:
It is the purpose of this paper to record information concerning the distribution and occurrence of manganiferous concretions and other manganese oxide deposits that develop on certain lake bottoms. During the summer of 1935 several days were devoted to a study of this type of lake bottom deposit in various parts of Nova Scotia. Lake studies in Ontario have extended the known distribution from lakes on or near the Atlantic coast to lakes in southern Ontario. During the writer's first work on lacustrine manganiferous deposits the concretions of manganese oxide which were found were almost entirely limited to the relatively shallow parts of the lakes examined. Other lakes are now known where the manganese oxide appears to occur only in the maximum depths.