高校地质学报
高校地質學報
고교지질학보
GEOLOGICAL JOURNAL OF CHINA UNIVERSITIES
2013年
2期
373-380
,共8页
焦永玲%汪洋%姚瑶%仝立华
焦永玲%汪洋%姚瑤%仝立華
초영령%왕양%요요%동립화
C型埃达克岩%大陆下地壳%部分熔融%相平衡
C型埃達剋巖%大陸下地殼%部分鎔融%相平衡
C형애체극암%대륙하지각%부분용융%상평형
C-type adakite%lower continental crust%partial melting%phase equilibrium
中基性(SiO2=50%~60%)成分源岩在中等压力(p=1.0~1.2 GPa,相当于35~40 km)下的失水部分熔融残留相中斜长石比例大,而石榴子石的比例不超过20%,与之平衡的中酸性熔体难以具备埃达克岩的地球化学特征。富钾源岩部分熔融体系中钾的地球化学行为不遵循稀溶液的Henry定律,基于强不相容假设的模拟计算很可能会过高估计熔体中的钾含量。
中基性(SiO2=50%~60%)成分源巖在中等壓力(p=1.0~1.2 GPa,相噹于35~40 km)下的失水部分鎔融殘留相中斜長石比例大,而石榴子石的比例不超過20%,與之平衡的中痠性鎔體難以具備埃達剋巖的地毬化學特徵。富鉀源巖部分鎔融體繫中鉀的地毬化學行為不遵循稀溶液的Henry定律,基于彊不相容假設的模擬計算很可能會過高估計鎔體中的鉀含量。
중기성(SiO2=50%~60%)성분원암재중등압력(p=1.0~1.2 GPa,상당우35~40 km)하적실수부분용융잔류상중사장석비례대,이석류자석적비례불초과20%,여지평형적중산성용체난이구비애체극암적지구화학특정。부갑원암부분용융체계중갑적지구화학행위불준순희용액적Henry정률,기우강불상용가설적모의계산흔가능회과고고계용체중적갑함량。
Dehydration melting of the intermediate-basic (SiO2=50%~60%) source undera pressure of 1.0~1.2 GPa (corresponding to 35~40 km depth) will generate high portion of plagioclase in the residuum, and the content of garnet in the residuum may not exceed 20% in most instances. Accordingly, the intermediate to acid melts, which are in equilibrium with such residuum, will not display the geochemical features of adakite. Meanwhile, the geochemical behavior of potassium in the partial melting system of K-rich sources does not obey the Henry's law of dilute solution, so the potassium content in the melt might be significantly overestimated by the calculation based on the assumption of the highly incompatible behaviour of potassium.