胶东地区三类金矿成矿系统地质地球化学及动力学

The East Shandong gold province is located on the southeastern margin of the North China Craton and features uplift in the north and depression in the south. The uplift area is made up of the Archaean Jiaodong Group, the Proterozoic Jingshan Group and Yanshannian granites. Most gold deposits in the uplift area are spatially associated with the Yanshannian granites. Two types of gold mineralization occur in the region: the quartz-vein type hosted in the Linglong granite suite, and the shear zone type hosted by either the Linglong granite or Guojialing granitoid suites. The mineralization ages are 113～126 Ma. The southern part of East Shandong contains the Mesozoic Jiaolai basin, which formed during regional extension. The basin is bounded by the Wulian-Rongcheng fault in the southeast and the Tanlu fault in the west. The Pengjiakuang, Fayunkuang and Dazhuangzi gold deposit occurs on the northeastern margin of the basin. The mineralization ages of these deposits are 110～128 Ma. This paper focuses on a low-angle detachment fault developed between the Proterozoic Jingshan Group metamorphic complex and the northeastern margin of the basin. Our field work shows that the distribution of the Pengjiakuang gold deposit was controlled by the detachment fault. Moreover, the Fayunkuang, Guocheng and Liaoshang gold deposits also occurr in the periphery of the basin, and their features are similar to Pengjiakuang gold deposit. The study of geological geochemistry of the gold deposits has shown: ①three-type gold deposit was situated in the Jiaodong area, including altered rock type (Jiaojia type), quartz vein type (Linglong type) and breccia type (Pengjiakuang type); the ore-forming materials and fluid for Pengjiakuang type gold deposit shows multiple source; ②the ore materials of Jiaojia and Linglong type deposits are mainly from deep source. The author has studied geological-geochemical dynamics of three types deposits in Jiaodong area. The study of tectonic dynamics shows that ore-forming structure differential stress values of Pengjiakuang gold deposit is 100 * 10~6～130 * 10~6 Pa, and that of Jiaojia gold deposit is 100 * 10~5～194 * 10~6 Pa. Dynamics of hydrothermal ore-forming fluid has also been studied in this paper. Author applies Bernoulli equation to dynamic model of hydrothermal fluid motion in brittle fracture and cracks (quartz vein type gold mineralization), and applies Darcy law to dynamic model of hydro thermal fluid motion in porous medium (altered rock type gold mineralization). Author does daring try in order to study quantitativly transport mechanism of hydrothermal ore-forming fluid in this paper. The study of fluid inclusions and crystal dynamics shows that reaction system of hydrothermal ore-forming includes three types, as follows: ore-forming reaction, controlling reaction and buffer controlling reaction. They depend on each other, controlling each other, which form a organic system. Further research shown that formation of ore shoots was controlled by coincidence processes of tectonic dynamic condition and thermodynamic evolution. This paper has summaried reginoal metallogenic laws and seted up metallogenic(dynamics) models for Jiaodong gold ore belt.

内蒙古黄岗矿集区与锡矿化有关的花岗岩成因研究

Muanggang-Dajing area located in the south end of Dahinggan Mts is the only discovered tin-polymetallic minerzalization belt and the only tectonic magmaism zone with middle-upper grade tin-ore deposites in North China. Tin mineralization in this area is believed tn related to Yanshannian granites which is different from those in South China tin belt. Through geochemical study of these granites on the base of fieldworks , thin section observation, major and trace elements as well as isotopic composision determination, the isochronic sequence and petrogenetic series for the granites have been determined. Hi light ing on the petrogenesis of earlier Yanshannian of MOmarh granites, two groups granites with different Neodymium isotopic features have been distinguished. Both belonging to hi-K calc-alkalinic series, their nature of source rocks and.magma processing were restricted, we argue for that the two groups have get the isotopic differences from their sources-middle and later proterozoic juvenial crustal via mantle underplating. From then on , there is a pre-enrichment of tin in this area. The partial melting from a F rich soruses can dissolve and carry more tin from the same some due to the de-connection of melt, which supply the mineralization fluids after a thoroughly evolement.

新疆准噶尔A型花岗岩的年代学和地球化学研究

新疆北部地区属于中亚造山带的关键部位，有独特的构造岩浆活动和成矿作用，自二十世纪八十年代早期以来一直是国内外地质研究的热点地区之一。准噶尔盆地两侧大面积出露的A型花岗岩及相关矿床是该区的重要研究对象。尽管已有的研究积累了一定成果，但对一些关键问题，特别是对于A型花岗岩形成时代和成因的认识还存在较大争议。另一方面，传统观点认为锡矿床主要与演化的过铝质S型花岗岩有关，但在东准噶尔卡拉麦里构造带，多个中小型锡矿床产于A型花岗岩体内或岩体与围岩的接触带附近，花岗岩与锡矿的成因联系有待深入研究。 本论文以准噶尔盆地两侧的三条A型花岗岩带（包括东准噶尔的卡拉麦里和乌伦古河A型花岗岩带、西准噶尔的达拉布特A型花岗岩带）为研究对象，对其中的一些A型花岗岩体开展了详细的年代学和地球化学研究，并以这些资料为基础，探讨了A型花岗岩的岩石成因及其构造和成矿意义。概括起来，主要得到以下结论性认识： （1）锆石U-Pb年代学结果显示，卡拉麦里铝质和碱性A型花岗岩都形成于302~310Ma左右；乌伦古河碱性A型花岗岩形成于305~320Ma，而铝质A型花岗岩形成于270~280Ma；西准噶尔达拉布特铝质A型花岗岩形成于295~305Ma。这些高精度的同位素年龄资料进一步确证了准噶尔地区大面积发育的A型花岗岩是该区后碰撞阶段的岩浆作用产物。 （2）三个构造带的碱性花岗岩和碱长花岗岩都具有典型A型花岗岩的矿物学和地球化学特征。在主量元素上它们富硅、富碱、低铝、贫钙镁，在微量元素上它们明显富集Rb、K、Th等大离子亲石元素及Zr、Hf等高场强元素和稀土元素而亏损Ba、Sr、Eu。根据地球化学组成，苏吉泉黑云母碱长花岗岩是典型的铝质A型花岗岩，而不是前人提出的S型花岗岩。 （3）三个构造带的A型花岗岩均有较高的正Nd(T)值和大于成岩年龄的两阶段Nd同位素模式年龄，它们的地质特征和地球化学组成难以用幔源岩浆高度分异的成岩模式解释。这些A型花岗岩的岩浆很可能是花岗闪长质岩浆分异结晶作用的产物，而花岗闪长质岩浆则起源于具亏损地幔同位素组成的玄武质洋壳和少量陆壳物质的部分熔融。 （4）东准噶尔早二叠世A型花岗岩的发育表明该区后碰撞阶段的花岗岩浆作用持续时间较长（约60Ma），这些花岗岩与晚石炭世A型花岗岩在地球化学组成上的差异揭示了东准噶尔乃至新疆北部在早二叠世的陆壳垂向生长。 （5）萨惹什克锡矿石中辉钼矿的Re-Os同位素年龄值（307Ma）与赋矿的萨北碱性花岗岩中锆石的U-Pb年龄值（306Ma）有很好的一致性，而且辉钼矿的Re含量低，表明成矿物质可能主要源于地壳。时间和物源的证据反映该区A型花岗岩与锡矿床具有密切的成因联系。

花岗岩-LiF-NaF-H_2O体系液相不混溶的实验研究

Liquid segregation phenomena have been found and explained in the F(Li)-rich granites in south China by Wang Linakui et al. (1979; 1983). A number of experimental investigations into the liquid immiscibilities in the granites systems have been carried out (Anfilogov et al., 1983; Glyuk et al., 1971; Glyuk et al., 1973a; 1973b; kovalenko, 1978; Wang Liangkui et al., 1987). Nevertheless, the detailed scenarios of the liquid immiscibilities in the granitic magmas are much less understood. This experimental study is amide to get access to this problem. Starting materials are biotite granite +LiF(3-10%)+NaF(3-10%)+H_2O(30%). The experimental results have shown that the liquid immiscibilities of melts of different compositions occur at 1 kbar and 840 ℃ when 5wt% (LiF + NaF) are added to the granite samples. three kinds of glasses indicating of three types of coexisting immiscible melts have been observed: light blue matrix glass, melanocratic glass balls and leucocratic glass balls. It is interesting that we have observed various kinds of textures as follows: spherulitic texture, droplets, flow bands, swirls. All these textures can be comparable to those in the natural granitic bodies. Electron microprobe data suggest that these different kinds of glasses are of different chemical compositions respectively; matrix glasses are F-poor silicate melts; melanocratic balls correspond to F-rich silicate melts; and leucocratic balls are the melts consisting mainly of fluorides. Raman spectrometric data have indicated that different glasses have different melt structures. TFM Diagrams at 1000 * 10~5 Pa have been plotted, in which two miscible gaps are found. One of the two gaps corresponds to the immiscibility between F - poor silicate melt and F-rich silicate melt, another to that between the silicate melt and fluoride melt. The experiments at different pressures have suggested that the decreases in pressures are favorable to the liquid immiscibility. Several reversal experiments have indicated that the equilibria in different runs have been achieved. We have applied the experimental results to explain the field evidence of immiscibilities in some of granites associated with W-Sn-Nb-Ta mineralization. These field phenomena include flow structure, globular structures,mineralized globular patche and glass inclusions in topaz. We believe that the liquid immiscibility (liquid segregation) is a possible way of generation of F(Li)-rich granites. During the evolution of the granitic magmas, the contents of Li, F, H_2O and ore-forming elements in the magmas become higher and higher. The granites formed in the extensional tectonic settings commonly bear higher abundences of the above-mentioned elements. the pressures of the granitic magmas are relatively lower during the processes of their emplacements and cooling. The late-staged magmas will produce liquid immiscibilities, leading to the production of several coexisting immiscible melts with different chemical compositions. The flow of immiscible consisting magmas will produce F(Li)-rich granites. It is also considered that liquid immiscibilities are of great significance in the production of rare metal granites. The ore-forming processes and magmatic crystallization and metasomatic processes can be occur at the same time. The mineralisations of rare metals are related to both magmatic and hydrothermal processes.