(Table 1) Major and trace elements at DSDP Leg 57 Holes

Several papers have recently appeared concerning the metalliferous sediments on the active oceanic ridges. The geochemistry of such sediments is reasonably well understood and the deposits generally considered to be products of volcanic processes (Boström and Peterson, 1969; Boström et al., 1969; Horowitz, 1970, 1974; Cronan et al., 1972; Cronan and Garrett, 1973; Piper, 1973). The geochemistry of trench sediments, however, is less well known. There is a great need for studies of trench inner slope sediments, particularly in view of the significance of such sediments as a record of the effects of oceanic plate subduction under the continental crust. Sampling by Glomar Challenger in the trench inner slope was therefore of utmost importance in determining the origin of trench inner slope deposits.

近期已有多项学术研究针对活动洋脊（active oceanic ridges）上的含金属沉积物（metalliferous sediments）展开报道。此类沉积物的地球化学特征已得到较为充分的认知，且这类沉积普遍被认为是火山作用的产物（Boström与Peterson，1969；Boström等，1969；Horowitz，1970、1974；Cronan等，1972；Cronan与Garrett，1973；Piper，1973）。然而，海沟沉积物的地球化学特征却鲜少被探明。当前亟需开展海沟内坡（trench inner slope）沉积物的相关研究，尤其是考虑到此类沉积物可作为大陆地壳下大洋板块俯冲（oceanic plate subduction）效应的记录载体，具备极高的研究价值。因此，借助格洛玛·挑战者号（Glomar Challenger）对海沟内坡进行沉积物取样，对于明确海沟内坡沉积的成因而言至关重要。