CAJ | 학술논문

新疆北部西准噶尔、吐哈盆地、东天山、西天山以及塔里木东北缘广泛发育的二叠纪(260~290 Ma)基性岩墙群与塔里木大火成岩省形成时代相近.基性岩墙群主量元素与 MgO 含量具有较好的相关性,富集Rb、Ba和Sr等大离子亲石元素以及轻稀土元素,亏损 Nb、Ta和 Ti 等高场强元素,无明显Eu异常,与岛弧岩浆特征相似.εNd(t)值为-11??25~7??86,初始N(87Sr)/N(86Sr)值为0．703~0．710.西天山基性岩墙群亏损轻稀土元素,塔里木东北缘亏损Sr.新疆北部二叠纪基性岩墙群岩浆可能起源于富集型软流圈地幔源区,岩浆演化过程中存在不同程度的地壳物质或俯冲交代岩石圈地幔的混染,其中西准噶尔、东天山、西天山和吐哈盆地岩墙经历了板片俯冲流体交代的岩石圈地幔混染,东天山及塔里木东北缘基性岩墙在岩浆演化过程中受到明显的地壳物质混染.新疆北部二叠纪基性岩墙群可能是地幔柱岩浆作用不同演化过程的产物.
신강북부서준갈이、토합분지、동천산、서천산이급탑리목동북연엄범발육적이첩기(260~290 Ma)기성암장군여탑리목대화성암성형성시대상근.기성암장군주량원소여 MgO 함량구유교호적상관성,부집Rb、Ba화Sr등대리자친석원소이급경희토원소,우손 Nb、Ta화 Ti 등고장강원소,무명현Eu이상,여도호암장특정상사.εNd(t)치위-11??25~7??86,초시N(87Sr)/N(86Sr)치위0．703~0．710.서천산기성암장군우손경희토원소,탑리목동북연우손Sr.신강북부이첩기기성암장군암장가능기원우부집형연류권지만원구,암장연화과정중존재불동정도적지각물질혹부충교대암석권지만적혼염,기중서준갈이、동천산、서천산화토합분지암장경력료판편부충류체교대적암석권지만혼염,동천산급탑리목동북연기성암장재암장연화과정중수도명현적지각물질혼염.신강북부이첩기기성암장군가능시지만주암장작용불동연화과정적산물.
Permian (260-290 Ma)mafic dyke swarms in the northern of Xinjiang widely develop in West Junggar,Turpan-Hami Basin,East Tianshan,West Tianshan and the northeast margin of Tarim.The formation age of mafic dyke swarm is similar to that of Tarim large igneous provinces.The correlations between contents of major elements and MgO of mafic dyke swarms are obvious.Mafic dykes are enriched in large ion lithophile elements (Rb,Ba,Sr,etc.)and light rare earth elements (LREE),and depleted in high field strength element (Nb,Ta,Ti, etc.),and there is no obvious Eu anomaly,the characteristics are similar to island arc magma.εNd(t)values of mafic dykes are -11.25-7.86,and the initial N(87Sr)/N(86Sr)values are 0??703-0??710.Mafic dyke swarms in West Tianshan are depleted in LREE,and those in the northeast margin of Tarim are depleted in Sr.The magma of Permian mafic dyke swarm in the northern of Xinjiang is probably originated from enriched asthenosphere mantle source,and experiences different degrees of contamination of crust materials or metasomatic lithospheric mantle with subduction in the process of magmatic evolution.The dykes in West Junggar,East Tianshan, West Tianshan and Turpan-Hami Basin experience the contamination of lithospheric mantle with metasomatism of fluids from plate subduction;the mafic dykes in East Tianshan and the northeast margin of Tarim experience obvious contamination of crustal materials in the process of magmatic evolution.The Permian mafic dyke swarms in the northern of Xinjiang could be the products of mantle plume magmatism in different processes of evolution.