| The Qinling Orogenic Belt(QOB)is an important part of the Central Orogenic Belt,renowned abundant reserves of Au,Pb–Zn,Hg–Sb and other valuable mineral resources,and represents a prominent research area for gold and polymetallic mineralization both domestically and internationally.The study area is situated in the eastern part of the West Qinling Belt(WQO),at the convergence and inflection parts of the Hehei-Lintan-Liangdang and Zhouqu-Chengxian-Huixian deep arc faults.The metallogenic geological conditions in this region are highly favorable,and the geochemical anomaly is strong,exhibiting immense prospecting potential.In the study area,44 deposits have been discovered,including the Daqiao super-large-scale Au deposit,Anfangba and Liangbianpo medium-scale Au deposits,Yawan large-scale Sb deposit,Zuojia and Taishan medium-scale Sb deposits,as well as several small-scale Au,Sb,Pb–Zn and Cu deposits and ore occurrences.Although significant progress has been made by previous researchers in the field of exploration,geological characteristics,and genetic research of these deposits,there still exist several scientific challenges:(1)There are substantial disagreements regarding the understanding of the genesis and metallogenic mechanisms of typical deposits;(2)Limited attention has been given to studying the key ore-controlling factors and mechanisms that restrict the formation of Au and Sb deposits.Additionally,a systematic summary is lacking concerning the spatio-temporal distribution of regional mineralization as well as ore deposit association;(3)The research on intergrated informational prognosis for Au and Sb deposit is weak,and the future direction for further prospecting remains unclear.These aforementioned issues significantly impede breakthroughs in prospecting.In order to address the aforementioned scientific issues,guided by the theory of intergrated informational prognosis for mineral and based on previous researches,this paper takes Yawan Sb deposit,Daqiao Au deposit,Guojiagou Au polymetallic deposit,and Jinchang Cu–Au deposit as typcal deposits,and investigates the geological characteristics,Indosinian magmatism,sources of ore-forming materials and fluids,and rock-forming and ore-forming ages,to determines the genetic type of these deposits.The ore-controlling factors and mechanism of Au–Sb mineralization are systematically analyzed,the spatio-temporal distribution of mineralization is summarized,and a regional ore-forming model is established.Based on this foundation,comprehensive geological interpretation and extraction of prospecting marker information are conducted using existing aeromagnetic,gravity,geochemistry,and remote sensing data to construct a regional comprehensive information prospecting model.Finally,this paper focuses on intergrated informational location prognosis and delineation of prospect for Au–Sb deposit using the evidence weight model on the MARS platform.The paper has yielded the following results and insights:1.The orebodies of Guojiagou Au polymetallic deposit and Jinchang Cu–Au deposit are located in the contact zone between the magmatite and the marble and tension faults.The ore-forming magmatite is composed of granodiorite and quartz diorite with ages of218-220Ma.They were generated by partial melting of Meso-Proterozoic high-K basaltic lower crust with the addition of mantle-derived melts,which had characteristics of rich water content and high oxygen fugacity.Ore-forming materials originate from magmatic rocks and strata,and the ore-forming fluids are the combination of magmatic water and pore water derived from the strata.These two deposits are skarn type with ore-froming ages of 213-218.1Ma,formed during syn-collision tectonic environment.The orebodies of Daqiao Au deposit and Yawan Sb deposit occurred in the Triassic strata,exhibiting distinct structural ore-controlling characteristics,and Au,Sb mineralization closely associated with silicification.The sources of ore-forming materials and fluids are magmatic rocks and the Triassic strata,and ore-forming fluids are mixed fluids of magmatic water,metamorphic water from Triassic strata,and meteoric water.These two deposits are classified as magmatic hydrothermal type,with ore-froming ages of 220～210 Ma(Daqiao)and 199.9 Ma(Yawan),respectively,formed during the tectonic transition from syn-collision to post-collision environment.2.Based on reduction to the pole,analytic prolongation,horizontal first-order derivative calculation and linear structure(representing physical structural plane)extraction,different heights vertical second-order derivative calculation and circular structure(representing boundary of physical geological bodies)of aeromagnetic and gravity data,this paper constructs a three-dimensional geological structure model,and proposes that the structural framework of the study area consists of NE-and NW-trending structures,a large-scale hidden magmatic pluton with low density and high magnetic characteristics is identified in the southeast of the study area.The Yaoshang-Shixia tectonic belt exhibits lateral trends to the Yawan-Daqiao area.The Au and Sb deposits in the study area are controlled by the NE-trending structures and its intersection with the NW-and NE-structures,occourring in the complex boundary changes of ore-forming geological bodies(low density and high magnetic geological bodies)or internal fault structures.Based on the results of stream sediment geochemical interpretation,the statistical analysis of ore-forming elements reveals that coefficient of variation of Bi,As,Au,Ag,Pb,Zn,Cd,Sb,and Hg et.are all greater than 2,which are the main ore-forming elements,consistent with the characteristics of ore mineral association.According to the results of cluster analysis and factor analysis,ore-forming elements can be divided into 5 combinations,including Au Sb As Bi Ag~2Cu~2Pb~2Zn~2W~2Hg~2(F1),Ag Pb Zn Hg Cd Au~2Mo~2Sb~2(F2),Cu WMo Mn Ag~2Ba~2Cd~2(F3),Sn Cu~2Pb~2Zn~2W~2(F4),and F5Ba Ag~2Cu~2Pb~2Zn~2W~2Hg~2(F5).Combined with the geological characteristics of the deposits,it is determined that Au Sb As Bi and Pb Zn Ag combinations are products of Au and Sb mineralization and Ag polymetallic mineralization in the study area,respectively.Factor load factor of Pb,Zn,Ag,Hg indicates their multi-stage mineralization characteristics.The presence of ore-forming elements Au,Sb anomalies and metallogenic factors F1,F2 anomalies serve as geochemical indicators for Au–Sb prospecting in the study area.The remote sensing interpretation identified one regional main linear structure,two primary linear structures,and a series of general linear structures.Additionally,it refined the selection of 11 optimal remote sensing anomalies.The NE-trending structure and its intersection and complex position control with NW and NE structures,as well as the remote sensing alteration anomaly,serve as key indicators in remote sensing prospecting.3.According to the study of typical deposits and comprehensive information geological interpretation,it has been determined that the Triassic strata,Indosinian magmatism,and faults/physical structural planes are the key ore controlling factors for Au–Sb mineralization in the study area.The lithologic association of ore-bearing surrounding rock determines the genetic type of the deposit(magmatic hydrothermal filling and replacement or skarn type).The Au–Sb metallogenic ages are concentrated in the Late Triassic,with skarn deposits forming earlier than magmatic hydrothermal deposits,and Au deposits forming earlier than Sb deposits.Spatially,Au–Sb deposits are mainly distributed near the contact zone between ore-forming plutons/gravity and magnetic interpreted buried plutons as well as surrounding rock within outer Triassic strata.There are zoning rules observed(Cu–Au near the contact zone of magmatic pluton,Au–Pb–Zn near Triassic strata close to magmatic pluton,and Au–Sb deposits in interrock structure belts/fault structure belts away from magmatic plutons).A regional Au–Sb metallogenic model and Metallogenic prediction model is studied and constructed.4.Based on Mineral Resource Evaluation System platform(MARS),using the evidence weight model,the present study has conducted research on the respective location prediction of Au and Sb deposit.The Triassic strata,the NE-trending line structure of gravity interpretation,the ring structure of gravity interpretation,the intersection site of gravity interpretation,the NE-trending line structure of aeromagnetic interpretation,the ring structure of aeromagnetic interpretation,the intersection site of aeromagnetic interpretation,the anomaly of Au element,the anomaly of F1 and F2mineralization factors,the NE-trending line structure of remote sensing interpretation and the abnormal area of remote sensing alteration are selected as the evidence factors for Au mineralization prediction;The Triassic strata,the NE-trending line structure of gravity interpretation,the NE-trending line structure of aeromagnetic interpretation,the anomaly of Au element,the anomaly of F1 and F2 mineralization factors,the NE-trending line structure of remote sensing interpretation and the abnormal area of remote sensing alteration are selected as the evidence factors for Sb mineralization prediction.Within the study area,4 A–type,7 B–type,3C–type prospects for Au deposit,as well as 3 A–type,7B–type,3 C–type prospects for Sb deposit have been delineated. |
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