南极Bransfield海峡海冰沉积物中的自生石膏

Autogenetic Gypsum in Marine Glacial Sediments in Bransfield Strait Antarctica

在本地区正常海盆的表层沉积物中首次发现了微晶与细晶两类自生石膏．根据石膏在沉积物中产出的特征以及沉积物孔隙水中Ｃａ２＋，ＳＯ４２－离子积明显超过其溶度积的事实表明，它们的生长是受沉积物粒间孔隙所提供的生长空间控制，并在孔除水过饱和的Ｃａ２＋，ＳＯ４２－的微地球化学条件下结晶出来，可能是沉积后早期成岩作用的产物．

Fine-crystalline and micro-crystalline gypsums with good preservation found in surface sediments in this study area are characteristic of the autogenetic origin in situ. Based on the characters of gypsum occurrence in sediments and the fact that the ion-products of Ca2+ and SO in interstitial water exceed obviously its solubility product, it is shown that the appearance of gypsum results mainly from conditions of growing space in sediments and micro-geochemical environment with the supersaturated Ca2+ and SO42- ininterstitial water.