Geology, geochemistry, and geochronology of the Dunde iron–zinc ore deposit in western Tianshan, China
Geology, geochemistry, and geochronology of the Dunde iron–zinc ore deposit in western Tianshan, China
复制标题
西天山敦德铁锌矿床地质、地球化学及年代学
DOI：
10.1016/j.oregeorev.2013.08.019
复制
发表时间：
2014-03
影响因子：
3.3
通讯作者：
Tian Jingquan
中科院分区：
文献类型：
--
作者：
Zhao Jun;Zhang Yongping;Li Fengming;Tian Jingquan
东德铁锌矿床（185mt，含铁35%）位于新疆天山造山带，赋存于晚石炭世火山—火山碎屑岩中，以进行夕卡岩形成和逆行蚀变为特征，矿石与侵入岩缺乏明确的空间联系。可识别出四个矽卡岩形成和矿床发育阶段：(1)形成粗长榴石（gr39 ~ 80; ad15 ~ 58）和二长石辉石（di63 ~ 97）的进阶矽卡岩阶段；(2)以磁铁矿为主的逆行矽卡岩期，含少量绿帘石、铁闪辉石、磷灰石、赤铁矿和微量钛矿、尖晶石；(3)硫化物阶段，主要形成砷化物（菱铁矿和毒砂）和硫化物矿物（闪锌矿、磁黄铁矿、黄铁矿、黄铜矿和少量方铅矿）、方解石和微量石英；(4)绿泥石—方解石阶段，以绿泥石、方解石和绢云母的形成为主要特征。硫化物期闪锌矿中有水滴状斑片状的黄铜矿出溶，出溶温度为350 ~ 400℃。因此，早期磁铁矿的结晶温度可能在100 ~ 400℃。方解石中存在丰富的流体包裹体，包括含儿矿物H2O、H2O和纯H2O包裹体。H2O包裹体的均一温度范围为147 ~ 367℃，盐度为2.4 ~ 23.4 wt.% NaCl当量。含儿矿水包裹体均一温度为172 ~ 347℃，盐度为31.9 ~ 33.0% wt.% NaCl当量。使用绿泥石地温计，绿泥石形成的温度被限制在152°C和222°C之间（平均= 194°C）。磁黄铁矿、闪锌矿、黄铁矿和菱铁矿的硫同位素组成δ34S值在3.8‰~ 8.1‰（平均δ34S = 6.8‰）范围窄，表明硫为岩浆成因。锆石LA-ICP-MS U-Pb定年结果表明，英安岩的206pb /238U加权平均年龄为316.0±1.7 Ma。结合以往磁铁矿化闪长岩、闪长岩脉和石榴石夕卡岩的定年结果，推断敦德铁锌矿床形成于晚石炭世，时间为316 Ma，与深部闪长岩侵入有关。晚石炭世，本区构造环境由俯冲碰撞向伸展转变，并伴有深部幔源岩浆基底。铁锌矿床形成后，顿德地区被早二叠世钾长石花岗岩侵入，锆石LA-ICP-MS U-Pb年龄为295.75±0.71 Ma。
The Dunde iron–zinc deposit (185 Mt at 35% Fe), located in the Tianshan orogenic belt, Xinjiang, northwest China, is hosted in late Carboniferous volcanic–volcaniclastic rocks characterized by prograde skarn formation and retrograde alteration, but the ore lacks any clear spatial link with intrusive rocks. Four stages of skarn formation and ore development can be recognized: (1) a prograde skarn stage that formed grossularitic garnet (Gr39–80; Ad15–58) and diposidic pyroxene (Di63–97); (2) a retrograde skarn stage dominated by the formation of magnetite with minor epidote, ferropargasite, apatite, hematite, and trace amounts of titanite and spinel; (3) a sulfide stage dominated by the formation of arsenide (loellingite and arsenopyrite) and sulfide minerals (sphalerite, pyrrhotite, pyrite, chalcopyrite, and minor galena), calcite, and traces of quartz; and (4) a chlorite–calcite stage mainly characterized by the formation of chlorite, calcite, and traces of sericite. Exsolution of droplet-like and patchy chalcopyrite is developed within sphalerite of the sulfide stage, indicating an exsolution temperature of 350–400 °C. As such, the crystallization temperature of early stage magnetite may have been > 400 °C. Abundant fluid inclusions occur in calcite, which include daughter-mineral-bearing H2O, H2O, and pure H2O inclusions. The H2O inclusions have a wide range of homogenization temperatures from 147 °C to 367 °C with salinities of 2.4–23.4 wt.% NaCl equivalent. The daughter-mineral-bearing H2O inclusions have homogenization temperatures from 172 °C to 347 °C with salinities of 31.9–33.0 wt.% NaCl equivalent. Using the chlorite geothermometer, the temperature of chlorite formation is constrained to be between 152 °C and 222 °C (average = 194 °C). Sulfur isotope compositions of pyrrhotite, sphalerite, pyrite, and loellingite have a narrow range of δ34S values from 3.8‰ to 8.1‰ (average δ34S = 6.8‰), suggesting that the sulfur was magmatic-derived. Zircon LA–ICP-MS U–Pb dating of wall rock dacite yields a weighted mean206Pb/238U age of 316.0 ± 1.7 Ma. Combined with previous dating results of magnetite-mineralized diorite stocks, diorite dikes, and garnet skarn, it can be inferred that the Dunde iron–zinc deposit formed in the late Carboniferous after 316 Ma and is genetically related to deep dioritic intrusions. During the late Carboniferous, the tectonic setting of this region changed from subduction–collision to extension, accompanied by mantle-derived magma underplating in deep. After the formation of the iron–zinc ore deposit, the Dunde district was intruded by an early Permian K-feldspar granite that yields a zircon LA–ICP-MS U–Pb age of 295.75 ± 0.71 Ma.
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DOI：
10.1007/978-3-319-78527-1
发表时间：
1973
期刊：
Stable Isotope Geochemistry
影响因子：
--
作者：
J. Hoefs
通讯作者：
J. Hoefs
影响因子：
5.8
作者：
Chen, Huayong;Clark, Alan H.;Moody, Timothy C.
通讯作者：
Moody, Timothy C.
影响因子：
2.6
作者：
Ya. N. Belevtsev
通讯作者：
Ya. N. Belevtsev
影响因子：
3.3
作者：
Jin‐Jie Yu;Yuchuan Chen;J. Mao;F. Pirajno;Chao Duan
通讯作者：
Jin‐Jie Yu;Yuchuan Chen;J. Mao;F. Pirajno;Chao Duan
影响因子：
3
作者：
Bo Wang-;L. Shu;Dominique Cluzel;M. Faure;J. Charvet
通讯作者：
Bo Wang-;L. Shu;Dominique Cluzel;M. Faure;J. Charvet