摘要
东天山尾亚钒钛磁铁矿矿床是北疆地区最大的钒钛磁铁矿矿床,其含矿岩系为一套偏碱性的镁铁-超镁铁质杂岩。含矿岩石主要造岩矿物橄榄石、辉石、角闪石、黑云母和斜长石的化学成分与铁质系列的镁铁-超镁铁岩成分相似或相同;辉石、角闪石、黑云母等矿物以富钛为特点,这些矿物中Ti、Fe等在早期形成的岩石(辉橄岩、橄榄辉长岩)中较晚期岩石中有明显富集。含矿辉长岩的锆石LA-ICPMS U-Pb同位素定年结果为236±3Ma,主要成岩时代为中三叠世,代表后碰撞结束阶段的成矿作用。这套含矿镁铁-超镁铁杂岩的Sr-Nd同位素特征以ε_(Nd)(t)均为正值,(^(87)Sr/^(86)Sr)_i值较低为特征,与原始地幔相近,但在岩浆上移过程中可能有陆壳物质加入。
Weiya V-Ti-magnetite deposit in Eastern Tianshan is the biggest one in North Xinjiang which the host rock belongs to a set of partial to alkalic mafic-uhramafic complex. Composition of main rock-forming minerals such as olivine, pyroxene, amphibole, biotite and plagioclase is in accord with that of ferruginous mafic-uhramafic rocks. Pyroxene, amphibole and biotite distinctly are Ti-rich, and the Ti and Fe contents commonly enrich in early stage rocks （ e. g. pyrolite and olivine gabbro ）. LA-ICPMS isotopic dating of zircon from gabbro is 236 ± 3Ma which means the diagenetic age of Middle Triassic and represents an end stage of postcollisional mineralization, The Sr-Nd isotope of the host mafic-ultramafic complex is characterized by identically positive εNd （t） value and lower （^87 Sr/^86Sr） ;value, which suggests that the magma might be derived from mantle but mixing into continental crust material during magma moving up.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2008年第4期781-792,共12页
Acta Petrologica Sinica
基金
国家重点基础研究项目(编号:2007CB411304和2001CB409806)
国家自然科学基金(批准号:40672061)资助
