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哈旦逊岩体位于准噶尔北东缘玛因鄂博断裂以南,受断裂构造控制,呈近三角形。该岩体岩石类型较复杂,主要岩石组合为石英二长岩、二长岩、辉长岩、闪长岩、二长花岗岩、钾长花岗岩等。二长岩中锆石SHRIMPU-Pb测年结果为289.5±3.6Ma。除个别辉长岩样品为钙碱性系列外,其它所有样品属于碱性系列。辉长岩的稀土总量(∑REE)为43×10-6～88×10-6,Eu异常不明显,轻稀土富集(LaN/YbN=2～6),微量元素含量变化趋势一致且富集大离子元素,Cr、Ni含量低。中性岩的∑REE大于100×10-6,轻稀土元素表现出不同程度的富集(LaN/YbN=6～20),具有不明显或是弱的Eu正异常。微量元素含量变化大,但总体变化趋势一致,即表现出大离子亲石元素(LILE)富集而高场强元素(HFSE)亏损。花岗岩的稀土元素组成可以分两类,一类具有中等到弱的Eu负异常(δEu=0.7～1.0),轻稀土强烈富集(LaN/YbN=12～30),其微量元素的原始地幔标准化配分模式与中性岩近于一致;另一类具有显著的Eu负异常(δEu=0.1～0.3),轻重稀土的分异不明显(LaN/YbN=3～8)。在微量元素配分模式中,有显著的Ba、Sr、P、Ti的亏损。不同岩石类型显示出Sr初始值异常低(0.7036～0.7039)和正的εNd(t)初始值(～6.5)。综合野外观察、岩石学及地球化学特征,推测辉长岩部分来自被俯冲带流体交代的亏损岩石圈地幔,而花岗岩部分来自年轻的基性下地壳重熔,熔融发生的深度大约在30～40km,使其中的部分酸性岩浆出现典型的高Ba-Sr花岗岩的特征。基性岩浆和酸性岩浆在上升过程中发生混合,闪长岩及二长岩可能是它们混合的产物。哈旦逊岩体形成于造山后伸展构造背景,壳幔岩浆的混合可能是造成新生陆壳生长的一种重要方式。
The Hudson rock is located to the south of the Mane Obo fault in the northern east Junggar and is controlled by the fault structure and has a nearly triangular shape. The rock body rock type is more complicated, the main rock assemblage is quartz monzogranite, monzonite, gabbro, diorite, monzogranite, potash-granite and so on. The zircon SHRIMPU-Pb dating of the monzonite is 289.5 ± 3.6Ma. All samples except for individual gabbro samples are alkaline series. The total REE of gabbro (ΣREE) is 43 × 10-6 ~ 88 × 10-6, the Eu anomaly is not obvious, light rare earth is enriched (LaN / YbN = 2 ~ 6), the trend of trace elements is the same Enriched with large ionic elements, Cr, Ni content is low. The ΣREE of the neutral rocks is more than 100 × 10-6, and the light rare earth elements show different degrees of enrichment (LaN / YbN = 6-20), with the obvious or weak Eu positive anomaly. The content of trace elements varied greatly, but the overall trend was the same, that is, LILE enrichment and HFSE loss. The REE composition of granites can be divided into two types, one is the moderate to weak Eu anomaly (δEu = 0.7-1.0), the light rare earth is strongly enriched (LaN / YbN = 12-30) and the trace elements are mantle normalized The other type has a significant negative Eu anomaly (δEu = 0.1 ~ 0.3), with little difference between light and heavy rare earths (LaN / YbN = 3 ~ 8). In the trace element allocation model, there are significant losses of Ba, Sr, P and Ti. Different rock types show abnormally low initial values of Sr (0.7036-0.7039) and positive initial values of [epsilon] Nd (t) (-6.5). Based on the field observation, petrology and geochemistry, it is inferred that the gabbro is partly derived from the depleted lithospheric mantle, which was replaced by the fluid from the subduction zone, whereas the granite is partly remelted from the younger basal crust. The melting occurs at a depth of about 30-40 km , So that some of them acidic magma appear typical characteristics of high Ba-Sr granite. The basic magmatism and the acidic magma mix during the ascent, and diorite and monzonite may be the products of their mixture. The Hudsonon pluton was formed after the orogenic extension and tectonic setting. The mixing of crust-mantle magma may be an important way to cause the growth of the nascent continental crust.