【摘要】：老撾爬奔金礦床產(chǎn)出于昌都—思茅—南邦陸塊二疊系沉積巖地層中,是一個(gè)以灰?guī)r為容礦圍巖的中低溫?zé)嵋航鸬V床。礦體主要賦存于二疊紀(jì)灰?guī)r中,嚴(yán)格受地層和構(gòu)造破碎帶及片理化帶控制,呈層狀、似層狀和囊狀產(chǎn)出。本文在對爬奔地區(qū)金礦床地質(zhì)特征和主要控礦因素研究基礎(chǔ)之上,分析該礦流體包裹體、碳氧同位素以及微量元素分布特征與礦化關(guān)系,取得主要成果和認(rèn)識為：1、確認(rèn)了本區(qū)主要的含礦建造為二疊紀(jì)灰?guī)r(內(nèi)源碎屑沉積巖),為成礦提供了物質(zhì)基礎(chǔ),成礦流體在灰?guī)r地層內(nèi)的斷裂和裂隙中發(fā)生循環(huán)對流使金的活化,遷移,沉淀,富集成礦。2、研究區(qū)內(nèi)北東向斷裂帶為其成礦與控礦的主要因素,并經(jīng)過后期多次的疊加改造形成爬奔金礦。斷裂帶不僅是本區(qū)的導(dǎo)礦構(gòu)造,也為成礦提供其就位的空間。3、區(qū)域化探結(jié)果顯示As、Hg、Sb、Ti等元素組合異常,礦物組合上出現(xiàn)雄黃、雌黃、毒砂、辰砂、絹云母等一系列典型的低溫?zé)嵋旱V物組合,說明熱液溫度較低。還可見少量閃鋅礦、方鉛礦、黃銅礦、黃鐵礦等,以此確定為礦熱液為中—低溫巖漿期后流體,這也與包裹體測溫結(jié)果一致(120°～340°)。4、根據(jù)爬奔金礦地質(zhì)地球化學(xué)分析結(jié)果可以認(rèn)為,礦床成礦流體總體具中低溫、多期段的特點(diǎn)。金礦成礦存在2期：第一期溫度較高,大于300℃；第二期160～240℃流體包裹體較高溫階段鹽度變化范圍為(1.22～2.55)wt%,平均值為1.77wt%,較低溫階段鹽度變化范圍為(4.17～16.7)wt%,平均值為7.64wt%,總體鹽度較低,說明其成礦流體主要為巖漿期后熱液,同時(shí)伴隨著大氣水熱液的存在,可能為混合熱液。礦石方解石碳氧同位素13Cv-PDB(‰)值分布在-4.5--5.2之間,18Ov-SMOW(‰)值分布于20.0-20.8之間,礦區(qū)樣品同位素組成特征相對集中,表明其成因單一,為同成因。綜上所述,爬奔金礦成因可認(rèn)為是受斷裂控制,成礦物質(zhì)來源于圍巖,斷裂活動(dòng)為成礦主要?jiǎng)恿C(jī)制。因此,爬奔金礦是受斷裂控制的巖漿熱液體系加古大氣降水混合作用而形成的中低溫?zé)嵋航淮涮畹V床。
[Abstract]:The Changdu-Simao-Nanbang gold deposit, which occurs in the Permian sedimentary strata of Changdu-Simao-Nanbang block, is a medium-low temperature hydrothermal gold deposit with limestone as its host rock. The orebodies mainly occur in Permian limestone and are strictly controlled by stratigraphic and structural fracture zones and sheet physical and chemical zones. They are stratiform, stratiform and cystic. On the basis of the study of geological characteristics and main ore-controlling factors of the gold deposit, the relationship between mineralization and fluid inclusions, carbon and oxygen isotopes, and the distribution of trace elements in the deposit is analyzed in this paper. The main achievements and understanding are: 1. It is confirmed that the main ore-bearing formations in this area are Permian limestone (endogenous clastic sedimentary rocks), which provides a material basis for mineralization. The circulation convection of ore-forming fluid in the faults and fissures of limestone strata causes gold to be activated, migrated, precipitated and enriched. The north-east fault zone in the study area is the main factor of metallogenic and ore-controlling. And after a number of late superposition transformation of the formation of the climbing gold deposit. The fault zone is not only the ore-conducting structure in this area, but also provides the space for metallogeny. The results of regional geochemical exploration show that the element assemblages, such as the assemblage of Asae Hgfen, Sbnti, and so on, are abnormal, and the mineral assemblages appear realgar, arsenopyrite, cinnabar, etc. A series of typical low temperature hydrothermal mineral assemblages, such as sericite, indicate that the hydrothermal temperature is relatively low. A small amount of sphalerite, galena, chalcopyrite, pyrite and so on can also be found. It is also consistent with the results of inclusion temperature measurement (120 擄~ 340 擄) .4.According to the geological and geochemical analysis of the Cepong gold deposit, it can be concluded that the ore-forming fluid of the deposit is generally of the characteristics of middle and low temperature and multi-stage. There are two stages of gold mineralization: the first stage is higher than 300 鈩，

本文編號：2140680