摘要
根据吉林汪清(WQ)中新世和辉南(HN)上新世玄武岩捕虏体橄榄岩透辉石的激光探针(LAM-ICPMS)微量元素分析结果,分析了华北北缘与兴蒙造山带结合部位陆下岩石圈地幔所经历的部分熔融作用和地幔交代作用。新生代时无论是靠近华北地块一侧的辉南,还是靠近兴蒙遣山带一侧的汪清陆下岩石圈除少量难熔地幔残留外,主体上均表现为显生宙‘大洋型’的地幔特征,即经历了8％以下的部分熔融作用。这些地幔又记录着复杂的地幔交代作用过程,交代介质类似于含水的、含碳酸岩质的硅酸岩熔体。这样的地幔特征与中国东部其他地区新生代时的主体岩石圈相似,也有少量古老地幔残余,由此进一步说明中国东部中、新生代岩石圈减薄作用经历了软流圈地幔对古老岩石圈的侵蚀和最终的置换过程。
This paper presents LAM-ICPMS trace element data of peridotitic diopsides from Cenozoic Wangqing and Huinan basalts, Jilin Province. It then discusses the nature of the lithospheric mantle including partial melting and metasomatism beneath the integrate position of the North China Craton and the Xingmeng Orogenic Belt. In Cenozoic, the lithospheric mantle is mainly characterized by the Oceanic affinity with minor relics of refractory one. The mantle recorded less than 8 % partial melting and experienced complex metasomatism by silicatitic and carbonatitic melts. It is found that the characters are similar to those of the main lithosphere mantle in Cenozoic from the other parts of the East China. The coexistence of the major newly accreted mantle with minor relics of refractory one in the area proves the mantle replacement in the Mesozoic-cenozoic lithospheric thinning.
出处
《地质科技情报》
CAS
CSCD
北大核心
2006年第6期9-16,共8页
Geological Science and Technology Information
基金
国家自然科学基金项目(40425002)
关键词
橄榄岩
透辉石
微量元素
地幔置换作用
华北北部
peridotite
diopside
trace element
mantle replacement
northern part of North China
