| Chronology and Geochemistry of Volcanic Rocks in the Cretaceous Suifenhe Formation in Eastern Heilongjiang, China |
| |
| 作者姓名： | JI Weiqiang XU Wenliang YANG Debin PEI Fuping JIN Ke and LIU Xiaoming College of Earth Sciences Jilin University Changchun Jilin Bureau of Land and Mineral Resources of Jilin Province Changchun Jilin The State Key Laboratory of Continental Dynamics Northwest University Xi 'an Shaanxi |
| |
| 作者单位： | JI Weiqiang，XU Wenliang，YANG Debin，PEI Fuping，JIN Ke and LIU Xiaoming College of Earth Sciences，Jilin University，Changchun，Jilin 130061 Bureau of Land and Mineral Resources of Jilin Province，Changchun，Jilin 130061 The State Key Laboratory of Continental Dynamics，Northwest University，Xi 'an，Shaanxi 710069 |
| |
| 基金项目： | We thank the staff members of the State Key Laboratory of Continental Dynamics, Ma Yuguang and Mao Qian from the Institute of Geology and Geophysics, Chinese Academy Sciences, for their technical supports during analyses. This study is financially supported by the National Natural Science Foundation of China （Grant No. 40672038） and the Special Grant of 0il ＆ Gas Research （XQ-2004-07）. |
| |
| 摘 要： | Zircon U-Pb ages and geochemical data of volcanic rocks in the Suifenhe Formation in eastern Heilongjiang Province are reported, and their petrogenesis is discussed in this paper. The Suifenhe Formation mainly consists of basalt, andesite, and dacite. Zircon from andesite and dacite are euhedral in shape and show typical oscillatory zoning with high Th/U ratios (0.18-0.57), implying its magmatic origin. Zircon U-Pb dating results by laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) indicate that the 206Pb/238U ages of zircons from andesite range within 105-106 Ma, yielding a weighted mean age of 105.5±0.8 Ma (n=14), and that 206Pb/238U ages of zircons from dacite are between 90-96 Ma, yielding a weighted mean age of 93.2±1.3 Ma (n =13). The volcanic rocks from the Suifenhe Formation are subalkaline series and show a calc-alkaline evolutionary trend with SiO2 content of 47.69%-65.47%, MgO contents of 1.42%-6.80% (Mg#= 45-53), and Na2O/K2O ratios of 1.83-3.63. They are characterized by enrichment in large ion lithophile elements (LILE) and light-rare-earth elements (LREE), depletion in heavy rare earth elements (HREE) and high field strength elements (HFSE) (e.g., Nb, Ta, Ti), and low initial 87Sr/86Sr ratios (0.7041-0.7057) and positiveεNd(t) values (039-4.08), implying that they could be derived from a depleted magma source. Taken together, these results suggest that the primary magma of the volcanic rocks might originate from partial melting of the mantle wedge metasomatized by fluids derived from subducted slab under a tectonic setting of active continental margin.
|
| 关 键 词： | 黑龙江东部 白垩纪 绥汾河组 火山岩 年代学 地质化学 |
| 收稿时间： | 4/6/2006 12:00:00 AM |
| 修稿时间： | 2006-10-16 |
Chronology and Geochemistry of Volcanic Rocks in the Cretaceous Suifenhe Formation in Eastern Heilongjiang, China |
| |
| Authors: | JI Weiqiang XU Wenliang YANG Debin PEI Fuping JIN Ke and LIU Xiaoming College of Earth Sciences Jilin University Changchun Jilin Bureau of Land and Mineral Resources of Jilin Province Changchun Jilin The State Key Laboratory of Continental Dynamics Northwest University Xi 'an Shaanxi |
| |
| Abstract: | Zircon U-Pb ages and geochemical data of volcanic rocks in the Suifenhe Formation in eastern Heilongjiang Province are reported, and their petrogenesis is discussed in this paper. The Suifenhe Formation mainly consists of basalt, andesite, and dacite. Zircon from andesite and dacite are euhedral in shape and show typical oscillatory zoning with high Th/U ratios (0.18-0.57), implying its magmatic origin. Zircon U-Pb dating results by laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) indicate that the 206Pb/238U ages of zircons from andesite range within 105-106 Ma, yielding a weighted mean age of 105.5±0.8 Ma (n=14), and that 206Pb/238U ages of zircons from dacite are between 90-96 Ma, yielding a weighted mean age of 93.2±1.3 Ma (n =13). The volcanic rocks from the Suifenhe Formation are subalkaline series and show a calc-alkaline evolutionary trend with SiO2 content of 47.69%-65.47%, MgO contents of 1.42%-6.80% (Mg#= 45-53), and Na2O/K2O ratios of 1.83-3.63. They are characterized by enrichment in large ion lithophile elements (LILE) and lightrare-earth elements (LREE), depletion in heavy rare earth elements (HREE) and high field strength elements (HFSE) (e.g., Nb, Ta, Ti), and low initial 87Sr/86Sr ratios (0.7041-0.7057) and positive εNd(t)values (0.39-4.08), implying that they could be derived from a depleted magma source. Taken together,these results suggest that the primary magma of the volcanic rocks might originate from partial melting of the mantle wedge metasomatized by fluids derived from subducted slab under a tectonic setting of active continental margin. |
| |
| Keywords: | Suifenhe Formation volcanic rocks LA-ICP-MS zircon U-Pb dating geochemistry petrogenesis Cretaceous Heilongjiang Province |
| 本文献已被 CNKI 万方数据 等数据库收录！ |
| 点击此处可从《Acta Geologica Sinica》浏览原始摘要信息 |
| 点击此处可从《Acta Geologica Sinica》下载免费的PDF全文 |
|
