• 作者： 黃武良
• 作者服務機構： 國立臺灣大學地質研究所
• 中文摘要： 地殼—地函之界限（莫荷）和上部地函中震波低速帶的本性之知識，對於吾人在地面上所見之大構造及地質之變化的了解有其重要性。莫荷可能是由於岩石化學成分之不連續造成的，也可能是由於岩石之岩相的轉化所形成的。這兩個模式之可能性，在此特加討論。震波低速帶，一般相信是由於地函中含有微量之水份，使得地函之物質發生初熔而造成。但格陵卻認為初熔之現象可能沒發生，而震波速度之突然下降，是由於地函中礦物內含有許多二氧化碳之氣泡所致。新的高壓高溫之實驗結果，認為二氧化碳氣泡不可能存在於地函中，在80公里之深度內二氧化碳成分以碳酸鹽類之狀態存在，而在深於80公里它能使地函橄欖岩發生初熔。因此二氧化碳在低速帶中，使地函物質產生初熔之效力，似乎同水份一樣。格陵所認為固態之軟流圈可能不存在。
• 英文摘要： The knowledge of the nature of erust-mantle boundary (Moho) and seismic lowvelocity zone in the upper mantle, is pertinentto the understanding of the tectonic and thegeological processes on the surface of the earth.Moho could be due to the chemical discontinuityor the phase transition. Possibilities of thesetwo models were discussed. It is believed thatthe seismic lbw velocity zone may be causedby incipient melting due to the presence oftraces of water in the upper mantle. Greenconcluded that melting was not involved andthat the low velocity were caused by exsolutionof CO from dry silicate minerals. The newexperimental data shows that free CO , can notexist in the mantle; it is stored as carbonatesat depth less than 80 km and as liquids at depthmore than 80 km. CO appears to be as effectiveas water in causing incipient melting in lowvelocity zone. Green's solid-asthenosphere withexsoluted CO , may not exist.
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