排序方式： 共有2条查询结果，搜索用时 0 毫秒
1
1.
Samples of glaciomarine sediments and suspended matter from the eastern and central Weddell Sea Shelf were collected during the Norwegian Antarctic Research Expedition (NARE) in 1978/79. Ice-rafted clastic materials are in general the main sediment sources. On the eastern shelf, biogenic materials are abundant (sponges and bryozoan debris). Fine-grained materials, clastic and bioclastic, are additionally supported as fecal aggregates and by currents. The composition of the bottom sediments shows only small variations laterally and within the profiles. Dissolution of the biogenic materials appears to be slight. The suspended matter is dominated by fine silt and clay particles of clastic, biogenic (mainly diatoms) and authigenic (Fe, Mg-rich silicates) origin. Metalliferous particles (Fe, Ti, Zn, Cr, Ni-rich) of possibly anthropogenic and/or cosmic origin are observed. On the upper continental slope and the outer shelf the sedimentation rates are in the range of 2–5 cm/1000 years, which are slightly higher than for the rest of the shelf. The bioclastic glaciomarine deposits grade southward into bioclastic free sediments, showing that glaciomarine deposits outside an ice shelf may form a sequence of alternating bioclastic-rich and bioclastic-free layers. Similarly, late Precambrian carbonate tillite sequences, especially in the case of thin carbonate layers interbedded with tillite layers, may reflect variations in glaciomarine facies rather than interglacial/glacial cycles. 相似文献
2.
TORE O. VORREN ELEN ROALDSET 《Boreas: An International Journal of Quaternary Research》1977,6(1):53-69
Stratigraphic, textural, mineralogical, geochemical and palynological investigations indicate the existence of: lacustrine clay from late Eemian (Hovden thermomer); dark indicateclayey basal till of the Early Weichselian age (Hovden kryomer); lacustrine sediments from an Early or Middle Weichselian interstadial (Førnes thermomer); and basal till from Middle/ Late Weichselian (Førnes kryomer). The environment during the thermomers is discussed. 相似文献
1