中国地质
中國地質
중국지질
CHINESE GEOLOGY
2014年
4期
1242-1252
,共11页
吴涛涛%赵东芳%邵军%鲍庆中%王宏博
吳濤濤%趙東芳%邵軍%鮑慶中%王宏博
오도도%조동방%소군%포경중%왕굉박
铅锌银矿床%地球化学%LA-ICP-MS锆石U-Pb测年%矿床成因%比利亚谷
鉛鋅銀礦床%地毬化學%LA-ICP-MS鋯石U-Pb測年%礦床成因%比利亞穀
연자은광상%지구화학%LA-ICP-MS고석U-Pb측년%광상성인%비리아곡
lead-zinc-silver deposit%geochemistry%LA-ICP-MS zircon U-Pb dating%genesis%Biliyagu
比利亚谷铅锌银矿位于海拉尔-根河中生代火山盆地北西缘地区。该矿床赋存于上侏罗统满克头鄂博组酸性火山岩中,受北西向断裂构造控制,主矿体呈脉状产出。赋矿围岩流纹质火山角砾熔岩LA-ICP-MS锆石U-Pb测年结果表明,其成岩时代为(159.2±1.8) Ma,并依据赋矿围岩与成矿的关系推测成矿时代为晚侏罗世。矿床赋矿围岩流纹质火山角砾熔岩和流纹岩的主量元素具有富硅(68.31%~77.18%)、富钾(3.39%~4.28%)、低钠(0.14%~0.18%)、高铝(11.74%~14.93%)的特征,属高钾钙碱性系列;岩石REE总量较低(93.65×10-6~98.94×10-6),以轻稀土相对富集、轻稀土和重稀土分异明显、弱的Ce负异常和Eu负异常为特征;结合岩石具有亏损Sr、高度富集轻稀土等特征认为火山岩产于板内,与其有关的岩浆可能来源于上地幔,并混染了壳源物质。综合本次研究和区域构造演化特征,初步认为矿床形成于鄂霍次克板块剪刀式闭合时期的拉张伸展环境。
比利亞穀鉛鋅銀礦位于海拉爾-根河中生代火山盆地北西緣地區。該礦床賦存于上侏囉統滿剋頭鄂博組痠性火山巖中,受北西嚮斷裂構造控製,主礦體呈脈狀產齣。賦礦圍巖流紋質火山角礫鎔巖LA-ICP-MS鋯石U-Pb測年結果錶明,其成巖時代為(159.2±1.8) Ma,併依據賦礦圍巖與成礦的關繫推測成礦時代為晚侏囉世。礦床賦礦圍巖流紋質火山角礫鎔巖和流紋巖的主量元素具有富硅(68.31%~77.18%)、富鉀(3.39%~4.28%)、低鈉(0.14%~0.18%)、高鋁(11.74%~14.93%)的特徵,屬高鉀鈣堿性繫列;巖石REE總量較低(93.65×10-6~98.94×10-6),以輕稀土相對富集、輕稀土和重稀土分異明顯、弱的Ce負異常和Eu負異常為特徵;結閤巖石具有虧損Sr、高度富集輕稀土等特徵認為火山巖產于闆內,與其有關的巖漿可能來源于上地幔,併混染瞭殼源物質。綜閤本次研究和區域構造縯化特徵,初步認為礦床形成于鄂霍次剋闆塊剪刀式閉閤時期的拉張伸展環境。
비리아곡연자은광위우해랍이-근하중생대화산분지북서연지구。해광상부존우상주라통만극두악박조산성화산암중,수북서향단렬구조공제,주광체정맥상산출。부광위암류문질화산각력용암LA-ICP-MS고석U-Pb측년결과표명,기성암시대위(159.2±1.8) Ma,병의거부광위암여성광적관계추측성광시대위만주라세。광상부광위암류문질화산각력용암화류문암적주량원소구유부규(68.31%~77.18%)、부갑(3.39%~4.28%)、저납(0.14%~0.18%)、고려(11.74%~14.93%)적특정,속고갑개감성계렬;암석REE총량교저(93.65×10-6~98.94×10-6),이경희토상대부집、경희토화중희토분이명현、약적Ce부이상화Eu부이상위특정;결합암석구유우손Sr、고도부집경희토등특정인위화산암산우판내,여기유관적암장가능래원우상지만,병혼염료각원물질。종합본차연구화구역구조연화특정,초보인위광상형성우악곽차극판괴전도식폐합시기적랍장신전배경。
Located in the northwest of Hailar-Genhe Mesozoic volcanic basin, the Biliyagu lead-zinc-silver deposit occurs in the Upper Jurassic Manketouebo Formation acidic volcanic rocks and is controlled by the NW-trending faults, with the orebodies being mainly of vein type. LA-ICP-MS zircon U-Pb dating of rhyolitic volcanic breccia lava indicates that its age is (159.2 ± 1.8) Ma. Based on the relationship between the rock and the mineralization, the authors hold that the deposit was formed in late Jurassic. Major element geochemistry of rhyolitic volcanic breccia lava and rhyolite is characterized by high SiO2 (68.31%-77.18%), potassium (3.39%-4.28%), and aluminum (11.74%-14.93%) and low sodium (0.14%-0.18%), suggesting high potassium calc-alkaline series. The REE content of rocks is low (93.65 × 10-6-98.94 × 10-6), and has characteristics of high LREE and LREE/HREE ratios as well as weak Ce negative anomaly and Eu negative anomaly. Combined with the features of the rocks such as the loss of the Sr and the obvious enrichment of LREE, it is inferred that the volcanic rocks originated from the plate. The magma of rocks might have been derived from the upper mantle and mixed with crustal materials. Combining this study with regional tectonic evolution characteristics, the authors hold that the deposit was formed during the closure period of Okhotsk plate in a tensile extension environment.