胶东半岛大磨曲家金矿床成矿流体物理化学条件演化

胶东大磨曲家金矿床流体包裹体包括水溶液包裹体、富CO2包裹体和高盐卤水包裹体3种类型,前两者发育较多,高盐卤水包裹体发育极少。流体包裹体显微测温及盐度、密度、压力估算显示,水溶液包裹体均一温度为98~376℃,据冰点温度估算,盐度为0.53%~8.28%,水溶液包裹体均一压力低于50×105Pa;富CO2包裹体完全均一温度为255~348℃,盐度为2.42%~11.43%,均一压力为1 000×105~2 500×105Pa;富CO2包裹体中CO2均一温度为23.0~32.4℃,指示该类包裹体可能含有数量不等的CH4或H2S。静水压力体制下,根据纯CO2包裹体均一压力估算成矿深度约为1 km。在270℃左右,均一压力从富CO2包裹体到水溶液包裹体急剧降低,指示成矿流体在270℃左右可能发生过一次减压沸腾过程,成矿流体盐度和密度在270℃左右也有显著的变化。因此,沸腾作用及其引起的成矿流体物理化学条件的急剧变化可能是导致大磨曲家金矿床成矿物质沉淀的重要机制。     

胶东大磨曲家金矿床岩石磁组构、构造变形与金矿化

在胶东地区招远-平度断裂带上的大磨曲家金矿区选取了典型的构造区域进行岩石磁组构研究。沿着断裂带在不同构造部位的36个采样点钻取了112个定向岩心样品,所有样品均沿勘探线布置。磁组构研究显示,研究区以弱磁性岩石为主,总体上,胶东群变质岩的磁化率值较高,而玲珑黑云母花岗岩的磁化率值较低,尤以碎裂程度高的强蚀变岩的磁化率值最低;磁化率各向异性方位主要为NE向挤压,磁组构所指示的构造应力场与大磨曲家矿区的区域挤压应力方向是相同的;对具不同程度矿化的81线的Au含量与80线磁组构各向异性度(P值)进行对比研究发现,P值与金品位呈负相关关系;弱矿化糜棱岩中的金矿化在磁面理发育的岩石中较为发育,成矿晚期,Au元素含量随着岩石磁性的减弱而增加,特别是在强应变后弛豫阶段矿液充填于相对张性的石英脉中Au含量最高。     

Decrepitation Thermometry and Compositions of Fluid Inclusions of the Damoqujia Gold Deposit,Jiaodong Gold Province,China:Implications for Metallogeny and Exploration

The recently discovered Damoqujia (大磨曲家) gold deposit is a large shear zone-hosted gold deposit of disseminated sulphides located in the north of the Zhaoping (招平) fault zone, Jiaodong (胶东) gold province, China. In order to distinguish the temperature range of cluster inclusions from different mineralization stages and measure their compositions, 16 fluid inclusions and 5 isotopic geochemistry samples were collected for this study. Corresponding to different mineralization stages, the multirange peaks of quartz decrepitation temperature (250-270, 310-360 and 380-430℃(2) indicate that the activity of ore-forming fluids is characterized by multistage. The ore-forming fluids were predominantly of high-temperature fluid system (HTFS) by CO2-rich, and SO2-4-K type magmatic fluid during the early stage of mineralization and were subsequently affected by low-temperature fluid system (LTFS) of CH4-rich, and Cl--Na /Ca2 type meteoric fluid during the late stage of mineralization. Gold is transferred by Au-HS- complex in the HTFS, and Au-Cl- complex can be more important in the LTFS. The transition of fluids from deeper to shallow environments results in mixing between the HTFS and LTFS, which might be one of the most key reasons for gold precipitation and large-scale mineralization. The ore-forming fluids are characterized by high-temperature, strong-activity, and superimposed mineralization, so that there is a great probability of forming large and rich ore deposit in the Damoqujia gold deposit. The main bodies are preserved and extend toward deeper parts, thereby suggesting a great potential in future.     

山东龙口市大磨曲家金矿地质、地球化学模型浅析

龙口市大磨曲家矿区位于沂沫断裂带东侧，招平成矿带北端，玲珑金矿田特-东风矿床北东段。通过对该区的地质、地球化学的特征研究与分析，得出了该区地质、地球化学模型，指出了该区的找矿方向。     

山东招平断裂带大磨曲家金矿床流体包裹体初步研究

The Damoqujia gold deposit,discovered recently and located in the north of Zhaoping fault zone,is a large altered rock type deposit.In this paper,we report the preliminary research results of the fluid inclusions and discuss its metallogenic implications. The homogenization temperatures of fluid inclusions fall into four ranges:310～350℃,230～270℃,160～200℃and 110～150℃; corresponding to the four stages of hydrothermal ore-forming processes:coarse grain pyrite-milk white quartz stage(Ⅰ),smoky gray Au-bearing quartz-fine grain pyrite stage(Ⅱ),Au-bearing polymetallic sulfide-quartz stage(Ⅲ),and quartz-carbonate stage(Ⅳ). Ore-forming fluid is with low salinity and low density,ranging from 1.4 Wt_(NaCl)% to 13.6 Wt_(NaCl)% and from 0.48g/cm~3 to 1.03g/cm~3 respectively.The inclusions are dominated by H_2O and CO_2 in gaseous compositions,and Na~ and K~ in positive ions,SO_4~(2-)and Cl~- in negative ions of liquid compositions.Au-S complex is the major form for transportation of gold.The pressure varied from 260MPa to 340MPa during the formation of CO_2-bearing inclusions at the early mineralization;the fluids are rich in SO_4~(2-)and Na~ .The pressure is 26-49×10~5 Pa during the formation of the aqueous salt inclusions in late mineralization,the inclusions are rich in CI~-(F~-), Na~ .δ~(18)O_(qurrtz)is 10.64～12.68%o,and the correspondingδ~(18)O_(H_2)O andδD is-5.44～6.47‰and-95.52～-106.48‰respectively.Based on the studies about compositions and hydrogen and oxygen isotopes of inclusions,it is evidenced that ore-forming fluid is magmatic hydrothermal fluid in early period,but affected by meteoric water in late.     

山东龙口大磨曲家金矿床302 脉深部成矿预测

大磨曲家金矿床位于玲珑金矿田北端。区内共产出大小金矿脉23 条,其中302 脉为主要的开采矿脉,含3 个工业矿体。矿体主要产于主断裂面下盘,由黄铁绢英岩化碎裂岩组成,呈似层状或透镜体状。通过对302 脉矿体厚度、金品位及矿脉米克吨值等分析,矿脉在深部自南向北有较好的金矿化显示,是深部隐伏矿体的找矿标志。矿体厚度在垂向变化上显示由74 线到98 线逐渐降低。根据这些找矿标志,在302 脉深部预测5 处找矿靶区。     

胶东大磨曲家金矿床成矿流体成分及稳定同位素研究

通过对大磨曲家金矿床不同类型矿石、蚀变岩中石英单矿物流体包裹体群体气液相成分,探讨金成矿流体由高温到低温流体成分演化与金成矿过程,结果证实:流体包裹体气相成分以H2O为主,其次为CO2,其余为CH4,C2H6,H2S,少量样品检测到少量N2和Ar2.流体包裹体液相成分中,阳离子主要为Na 和K ,Ca2 次之,少数样品检测到Mg抖;阴离子主要为Clˉ和SO42-,Fˉ含量也较高.高温阶段CO2含量缓慢降低,CH4 C2H6总量变化较大;低温阶段CO2含量快速降低,H2S含量缓慢降低,CH4 C2H6总量呈现增加趋势.由高温阶段到低温阶段K 含量降低,Na 含量增加,Ca2 变化不明显;阴离子组成SO42-含量急剧降低,Fˉ含量缓慢增加,Cl-含量快速增加.成矿流体稳定同位素组成δD水(SMOW)为-106.48‰～-95.52‰,δ18O石()(SM()w)为10.64‰～12.68‰,换算与之平衡δ18O水(SMOw)为1.88‰～5.78‰,δ13Cco2(PDB)为-6.264‰～-4.271‰.稳定同位素组成说明大磨曲家金矿床成矿流体可能为深部来源,可能与地幔排气和矿区内煌斑岩岩浆活动有关.     

山东大磨曲家矿区成矿元素多重分形特征

通过矩方法,以无序数据集中不同品位级次内的频率为测度,研究了胶东大磨曲家金矿矿体及玲珑花岗岩、胶东群等近矿围岩的Au、Ag、As等主要成矿元素分布的广义谱曲线（Dq-q）和多重谱曲线（f（α）-α）特征.在权重-0.2≤q≤1.6时,结果显示矿体与近矿围岩中成矿元素品位分布的广义谱和多重谱特征存在明显的区别.矿体中三种成矿元素的广义谱曲线近似直线,而多重谱曲线的宽度较小,显示成矿元素品位级次密集,较为均匀,接近简单分形;近矿围岩中广义谱曲线弯曲明显,多重谱曲线的宽度较大,显示近矿围岩中元素品位级次范围较宽,相对不均匀.同时,矿体中多重谱曲线f（α）的极值所对应的α比近矿围岩中的小,代表最或然子集的品位增加,指示成矿元素在矿体中富集.多重分形分析显示矿体中的成矿元素较近矿围岩中变得更为富集而均匀.     

山东龙口大磨曲家金矿床地质特征及地球化学勘查模型

山东龙口市大磨曲家金矿区位于沂沭断裂带东侧,招平成矿带北端。矿床矿化类型为含金蚀变岩型,矿床经历了热液和表生 2 个成矿期及 5 个成矿阶段,围岩蚀变主要为硅化、绢云母化、钾化等。通过对 302 号脉坑道及钻孔岩心原生岩石地球化学特征研究,提出矿体前缘指示元素组合为 Hg-- As--Sb,近矿或矿体指示元素组合为 Au--Ag--Cu--Pb--Zn,矿体尾晕指示元素组合为 Bi--Co--Ni; 据此,建立了地球化学勘查模型。     

山东龙口大磨曲家金矿深部盲矿预测的构造叠加晕模型

大磨曲家金矿是产于招平主断裂内的蚀变岩型盲矿床，对该矿床的构造叠加晕特征进行了系统研究，建立了金矿深部盲矿预测的构造叠加晕理想模型，并取得了很好的找矿效果。