摘要
尚志中新世富碱的钾质系列玄武岩为白榴霞石岩、橄榄霞石岩、霞石碧玄岩和橄榄碧玄岩。岩石中似长石矿物大量出现,霞石和白榴石可以共存。稀土元素和大离子不相容元素的特征表明形成白榴霞石岩、橄榄霞石岩、霞石岩碧玄岩和橄榄碧玄岩的地幔熔融程度越来越高。主元素和微量元素的模拟计算表明,霞石岩岩浆为上地幔岩2～4％的熔融,碧玄岩为上地幔橄榄岩5～8％的部分熔融;这些岩浆形成时的温压条件为:霞石岩的T=1410～1430℃,P=22～23×10~8Pa;碧玄岩的T=1380～1430℃,P=20～23.5×10~8Pa。
Shangzhi alkali basalts located in the rim of Songliao basin are Neogone basalts of Yi-Su rift system. There are four types of volcanic rocks characterized by alkalic basalts enriched in potassium in this area, v hich are leucite nephelinite(LNE), olivine nephelinite (ONE), nephelite basanite(NBN) and olivine basanite(OBN).
Alkali basalts in this area are highly enriched in incompatable elements according to analyses of major and trace element data. The temporal sequence of these rock formations is LNE, ONE, NBN, OBN and the quantity of REE and LIL elements decreases in accordance with the sequence. The less the trace element quantity of rocks is, the greater the mantle lherzolite malts.
The various basahs of this area are evolution series of primary magma controlled by the upper mantle melts, the extent and depth of mantle melts control formation of primary magma of different components.
The imitated calculation Of major and trace elements indicates that nephelinite and basanite are formed by 2～4％, 5～8％ partial melts respectively. The temperature and pressure of formation of the rocks are T=1380～1430℃, P=20～23(×10~8 Pa) respectively.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
1990年第3期53-64,共12页
Acta Petrologica Sinica
关键词
玄武岩
钾质
新生代
矿物
演化
Cenozoic era
Potassium basalts
Mineral evolution
Trace elements
Partial melting
Primary magma
