摘要
位于古生代东西向构造岩浆带和中、新生代北东向构造岩浆带交汇处的延边地区，在中侏罗－早白垩世期间生成两套中－高钾钙碱性火山－侵入杂岩。中侏罗世（１８０－１７０Ｍａ），该区受Ｆａｒａｌｌｏｎ板块俯冲作用影响，在（２４—２７）×１０８Ｐａ，１０７８—１２３０℃和８０—９０ｋｍ深处，由地幔岩两阶段熔融产生玄武安山质岩浆，经分异演化生成一套低稀土元素且分异作用良好的火山岩系．晚侏罗世（１６０—１４５Ｍａ）期间，Ｆａｒａｌｌｏｎ板块向北东方向横推致使该地区缺乏岩浆活动。早白垩世（１４０—１３０Ｍａ）期间Ｉｚａｎａｇｉ板块向欧亚大陆低角度俯冲，该区在２５．５－２８．５）×１０８Ｐａ，１１１７—１１３８℃和８５—９５ｋｍ处生成玄武安山质岩浆，经分界演化形成一套高稀土分异作用较差的火山岩系。
In Yanbian area located at the intersection between the EW - trending Paleozoic tectonomagmatic belt and the NE-trending tectonomagmatic belt, two suites of moderate - high potassic cale-alkaline volcanic-intrusive complexes were formed in Middle Jurassic-Early Cretaceous.Due to the influence of subduction of Farallon plate in the period of 180 - 170ma (Middle Jurassic), two -stage melting of pyrolite at the depth of 80-90 km and under the condition of 24 - 27 × 108 Pa and 1078℃-1230℃ produced basaltic - andesitic magma,which in turn formed a suite of REE-deficient and well - differentiated volcanic rocks through unceasing differentiation and evolution.In 160 - 145 ma of Late Jurassic, there occurred northeastward transcurrent movement of Farallon plate and, as a result, magmatic activities were weak in this area.In 140-130 Ma of Early Cretaceous, low -angle subduction of Izanagi plate toward Eurasian continent took place. At the depth of 85- 95 km and under the condition of 25. 5- 28. 5× 108 Pa and 1117℃- 1138℃, basaltic - andesitic magma was formed, whiCh in turn produced a suite of REE-high and poorly-differentiated volcanic rocks.
出处
《岩石矿物学杂志》
CAS
CSCD
1996年第1期30-39,共10页
Acta Petrologica et Mineralogica
基金
国家自然科学基金
