Geodynamics of gold metallogeny in the Shandong Province,NE China: An integrated geological,geophysical and geochemical perspective     

《Gondwana Research》2014,25(3-4):1172-1202

The Shandong Province along the southeastern margin of the North China Craton is the largest gold producing region in China. The nature and extent of gold metallogeny between the Western Shandong (Luxi) and Eastern Shandong (Jiaodong) sectors display marked contrast. In this paper, we synthesize the information on mineralization and magmatism, S–Pb–H–O–C–He–Ar isotopic data of the ores and Sr–Nd–Pb–Hf isotopic data of the Mesozoic plutons from the Shandong region. Combined with the salient regional geophysical data, we discuss the geodynamic setting of the gold mineralization in Shandong. The age data converge to indicate that the peak of gold metallogeny in this region occurred at ca. 120 ± 10 Ma. The mineralization in Luxi area shows links with sources in the Tongjing and Yinan complexes. The ore-forming materials in the Jiaodong area were derived from multiple sources and show clear evidence for crust–mantle mixing. The Moho depth on both sides of the Tan–Lu fault is broadly similar with only a minor variation across the Tan–Lu fault. The LAB (lithosphere–asthenosphere boundary) in the Jiaodong region is shallower than that in the Luxi area. The Tan–Lu fault is identified as a major corridor for asthenosphere upwelling. Geochemical features show that the mantle beneath the Luxi area is mainly of EM1 type, whereas the mantle in the eastern part, close to the Tan–Lu fault shows mixed EM1 and EM2 features. In contrast, the mantle beneath the Jiaodong area is mainly of EM2 type, suggesting the existence of more ancient lithospheric mantle beneath the Luxi area, in comparison to the extensively modified lithospheric mantle and asthenosphere beneath the Jiaodong area. The gold metallogeny in Shandong Province occurred in the geodynamic setting of lithospheric thinning. The differences in the character and intensity of gold mineralization between the Western and Eastern Shandong regions might be a reflection of the contrasting tectonic histories. The Western Shandong region preserves imprints of destruction through the Yangtze plate collision which probably marks the prelude for gold metallogeny in Jiaodong area. Subsequent magmatic input and cratonic destruction through Pacific plate subduction provided the settings for the later widespread mineralization in multiple phases.  相似文献   

招远金矿区水体中硫同位素特征及其对污染来源的指示     

贾晓岑  周建伟  朱恒华  余露  张秋霞  朱越 《水文地质工程地质》2020,47(5):179-188

稳定同位素因其指纹效应已成为分析矿区污染来源的重要技术手段。文章以招远金矿区为例，应用硫同位素联合水化学分析、聚类分析及氢氧同位素分析招远金矿区水污染特征和成因。通过分析可知，矿区内地表水和地下水主要接受大气降水补给，水力联系密切。水化学类型以SO₄—Ca和SO₄—Na型为主，阴离子以SO₄2-为主，地表水和地下水的NO₃-和Cl-在空间上变异性较大。地表水硫酸盐含量普遍偏高，硫酸盐污染较为严重，高值区出现在玲珑金矿、金翅岭金矿和张星镇附近；而地下水高值区都出现在玲珑金矿附近，且SO₄2-浓度沿着径流方向逐渐降低。地表水中硫酸盐δ34S值介于1.8‰~9.8‰，地下水中硫酸盐δ34S值介于2.7‰~9.6‰，地表水和地下水硫酸盐含量受玲珑金矿硫化、玲珑花岗岩和胶东岩群影响明显。在地下水径流途中，有地表水入渗污染地下水的现象。另外，工业废水的排放也是硫酸盐含量升高的主要原因。研究表明:硫同位素在金矿区硫酸盐污染的来源和特征方面有很好的指示作用，是评价矿山开采对地下水污染的有效工具。  相似文献   

山东诸城地区下白垩统一新类型鸟类足迹     

张艳霞  孙业君  陈军  崔卫生  陈树清  王增涛 《地质论评》2024,70(1):2024010011-2024010011

1931年,Mehl报道的来自Dakota Group的Ignotornis mcconnelli是第一个被广泛接受的中生代鸟类足迹。目前,亚洲、北美洲、欧洲、非洲和南美洲都有白垩纪鸟类足迹的报道,尤其以东亚地区最为丰富。山东诸城张祝河湾恐龙足迹点保存了一枚完整的鸟类足迹,本文对该鸟类足迹进行了详细描述与对比。研究认为,该鸟类足迹区别于以往发现的鸟类足迹,根据其形态建立了新种：玲珑诸城鸟足迹Zhuchengornipes exquisitus。玲珑诸城鸟足迹造迹者可能为滨鸟类,形成于干旱气候下的滨浅湖环境。  相似文献   

Hydrothermal alteration associated with Mesozoic granite-hosted gold mineralization at the Sanshandao deposit,Jiaodong Gold Province,China     

《Ore Geology Reviews》2013

The Sanshandao gold deposit (reserves of more than 200 t Au and average grade of 3.96 g/t), located at northwestern edge of the Jiaodong Peninsula, eastern North China Craton, is one of the largest gold deposits in the Jiaodong gold province. In this deposit, disseminated- and stockwork-style ores are hosted in Mesozoic granitoids; mineralization and alteration are largely controlled by the regional Sanshandao–Cangshang fault. Host granitic rocks for the deposit display a complex paragenetic sequence of alteration and mineralization. Activities of the Sanshandao–Cangshang fault created structurally controlled permeability allowing for infiltration of hydrothermal fluids, leading to diffusive K-feldspar alteration on the two fault planes. Later, large scale diffusive sericitization symmetrically developed across the main fault, and partially overprinted the earlier K-feldspar alteration. Following the sericitization, relatively small scale silicification occurred, but now it is only retained in the hanging wall of the main fault. Subsequently, the fault gouge formed as a “barrier layer”, which is impermeable for later fluids to move upward. After that, strong pyrite–sericite–quartz alteration occurred only in the footwall of the main fault, and was accompanied by gold precipitation. The last stage carbonation and quartz-carbonate veins marked the waning of gold-related hydrothermal activity. Mass-balance calculations indicate complex behaviors of different types of elements during fluid–rock interaction. Most major elements were affected by intensive mineral replacement reactions. As expected, the fluid-mobile elements, LILE and LREE, generally show moderate to high mobility. It is notable that even the commonly assumed fluid-immobile elements, such as HREE and HFSE, tend to be changed to various degrees. In addition, Y–Ho, Zr–Hf and Nb–Ta fractionations are observed in altered domains. Studies on alteration assemblages and fluid inclusions suggest that the ore-forming fluids were characterized by low salinity (≤ 8.4 wt.% NaCl equiv.), moderate temperature (300–400 °C), weakly acidic (pH: 3–5), and relatively reducing (log f_O2: ~–28) characteristics. In this type of fluids, gold was most likely transported as Au(HS)₂⁻ complex. With alteration going on, log (a_K⁺/a_H⁺) of fluids generally decreased due to significant formation of secondary K-bearing minerals. In addition, there might be a decrease of f_O2 from pre-gold alteration stage to the main gold mineralization stage, and decrease of f_O2 was probably one of the factors controlling gold precipitation. The Sr and Nd isotopic compositions of hydrothermal minerals, combined with previous H–O and He–Ar isotopic studies, indicate that the hydrothermal fluids were mainly derived from crustal sources (e.g., degassing of felsic magmas and meteoric water), but with involvement of mantle derived components. The gold mineralization event just coincided with reactivation of the North China Craton, as marked by asthenosphere upwelling, voluminous igneous rocks, and high crustal heat flow, which may have provided sufficient heat energy and fluid input required for the formation of the gold deposits.  相似文献   

基于GIS的黄河三角洲地区控制点沉降初步分析          下载免费PDF全文

苏衍坤  孙现申  王历进  李雪莉 《海洋测绘》2010,30(5):32-35

黄河三角洲地区许多控制点存在着不同程度的沉降,个别点年沉降量高达8.01 cm。该三角洲地理环境复杂,控制网复测成本畸高,部分控制点甚至因地形变化而无法复测。为此,在无法应用常规变形分析理论方法的情况下,对该地区建国以来的测绘档案资料进行数据挖掘,利用G IS的空间分析方法,发现了一些用常规方法难以发现的规律,并进行了初步验证,进而对该类地区控制测量的一些现象重新分析,并总结了对建、管、用网的参考意义。  相似文献   

城市与工程测量EDM导线技术标准的分析   总被引：1，自引：0，他引：1  

严伯铎  任晔平 《海洋测绘》2006,26(4):15-20

基于导线测量误差理论与电磁测距(EDM)导线的特性,分析讨论了城市与工程测量EDM导线的各项技术参数,提出了各级EDM导线技术标准的建议,通过计算验证所给出的这些技术指标是合理可靠的。  相似文献   

熔融制样-X射线荧光光谱法测定电气石中12种主次量元素     

夏传波  成学海  张会堂  赵伟  王卿 《岩矿测试》2018,37(1):36-42

电气石是一类含硼的铝硅酸盐矿物,化学成分复杂、化学稳定性强,不易湿法分解,B_2O_3含量较高,导致其主次量元素的同时测定存在一定困难。本文采用熔融法制样,建立了X射线荧光光谱法测定电气石Na_2O、MgO、Al_2O_3、SiO_2、P_2O_5、K_2O、CaO、TiO_2、V_2O_5、Cr_2O_3、MnO、TFe_2O_3等主次量元素的分析方法。样品与四硼酸锂-偏硼酸锂-氟化锂(质量比为4.5∶1∶0.4)混合熔剂的稀释比例为1∶10,消除了粒度效应和矿物效应;在缺少电气石标准物质的情况下,选择土壤、水系沉积物及多种类型的地质标准物质绘制校准曲线,利用含量与电气石类似的标准物质验证准确度,测定结果的相对标准偏差小于4.2%。采用所建方法测定四种不同类型电气石实际样品,测定值与经典化学法基本吻合。本方法解决了电气石不易湿法分解和硼的干扰问题,测定结果准确可靠,与其他方法相比操作简便,分析周期短。  相似文献   

CO2‐Li‐Sr Rich Therapeutic Groundwater in Gounan Village,Yantai, Shandong Province     

SONG Yingxin  Lü Baoping  SONG Mingchun  YANG Dongming  YAO Chunmei 《《地质学报》英文版》2018,92(1):422-423

正Objective The Jiaodong area in Shandong Province of eastern China hosts abundant high-quality groundwater.Most of the mineral water sources in this area,including those in the Laoshan and Kunyu Mountains,occur in Mesozoic granites.The groundwater and mineral waters contain metasilicic acid and strontium but the latter is potable.  相似文献   

MVT矿床中与成矿有关热液方解石的地球化学判据——以青海多才玛超大型铅锌矿床为例          下载免费PDF全文

吴畏  宋玉财  庄亮亮  黄世强  胡戈  黄钢  田力丹  岳龙龙 《岩石矿物学杂志》2023,42(1):47-70

碳酸盐矿物是MVT型铅锌矿床最为常见的热液蚀变矿物,记录了成矿流体特征,其元素或同位素组成对示踪和定位矿体具有一定的指示意义,但由于该类矿床中碳酸盐矿物成因多样,单一的岩相学观察往往难以准确识别与成矿有关和无关的方解石,需要辅以地球化学手段来确定方解石成因。本文利用钻孔编录、岩相学观察、C-O-Sr同位素和原位微量与稀土元素组成分析等手段,探讨了青海多才玛超大型MVT铅锌矿床中与成矿有关和无关两期方解石的矿物化学特征。结果表明,多才玛矿床成矿前方解石(Cal1)空间上与矿体无相关关系,遍布于中二叠统九十道班组灰岩内,阴极发光呈暗棕色至棕黄色,无明显生长环带;成矿期方解石(Cal2)主要产于铅锌矿体内及其上盘围岩中,多呈砂糖粒状-皮壳状充填于围岩裂隙和溶孔内,阴极发光呈暗黄色至亮橙色,常发育生长环带。相对于Cal2, Cal1与围岩的C-O-Sr同位素组成更为接近,这表明水岩反应期间,Cal1组成受围岩影响更大,Cal2组成受影响更小;相比于Cal1,Cal2具有较高的Mn、Fe、Zn、Pb含量和U/Th、V/Cr值以及较低的LREE/HREE值、Mg、Sr含量和弱的Ce负异常,指示成矿...  相似文献   

造山型金矿中富CO_(2)高内压流体包裹体完全均一温度的有效测定实验研究——以东天山玉峰金矿床为例SCIEI北大核心CSCD     

于立栋  李胜虎  张静  何西恒  于学峰  单伟  迟乃杰 《岩石学报》2022,38(1):267-280

形成于中-深成条件下的造山型金矿的成矿流体属于H_(2)O-NaCl-CO_(2)体系,金矿化阶段的石英中发育大量的富CO_(2)流体包裹体。长期以来,用常规冷热台对其进行显微测温热力学研究时,较高的内压力会造成绝大多数CO_(2)充填度>0.4的包裹体在尚未达到完全均一状态前就发生爆裂或泄露,导致所测的完全均一温度值明显偏离真实值,甚至无法测得完全均一温度,这制约了对造山型金矿床成矿条件的认知。针对该问题,本文以东天山玉峰金矿床富金矿石中的H_(2)O-NaCl包裹体(A型)和H_(2)O-NaCl-CO_(2)包裹体(AC型)为研究对象,介绍了利用最新型热液金刚石压腔(HDAC-VT型号)测试富CO_(2)高内压的AC型包裹体完全均一温度的实验流程与结果,并将实验数据与Linkam THMSG600冷热台测得的A型、AC型包裹体的完全均一温度进行了对比分析。实验结果表明,热液金刚石压腔能够有效阻止富CO_(2)流体包裹体在升温过程中发生爆裂、泄露等非弹性体积改变现象的发生,从而获得有效的完全均一温度。同时,本文还提出了一个新的压力-温度拟合线两线相交法,对热液金刚石压腔所测富CO_(2)流体包裹体的完全均一温度数据进行校正,以最大程度上减少外压力造成的影响,获得更为接近真实成矿流体的完全均一温度。基于此,获得玉峰金矿床的成矿温度和成矿压力分别为312~343℃和181~268 MPa。本文的实验研究工作显示了热液金刚石压腔在中-深成造山型金矿富CO_(2)成矿流体的研究领域具有重要应用前景。  相似文献