| 李得华,华永成,胡 月.甘肃省德合茂岩体岩石地球化学特征及成矿意义[J].甘肃地质,2025,34(3):8-16 |
| 甘肃省德合茂岩体岩石地球化学特征及成矿意义 |
| GEOCHEMICAL CHARACTERISTICS AND METALLOGENICSIGNIFICANCE OF INTRUSIVE ROCKS IN THEDEHEMA AREA OF GANSU PROVINCE |
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| DOI： |
| 中文关键词: 地球化学特征 构造环境 成岩成矿关系 德合茂地区 西秦岭 |
| 英文关键词:geochemical characteristics tectonic environment petrogenesis and mineraization relationship Dehemao area West Oinling |
| 基金项目:中国地质调查局“甘肃省夏河一合作地区金矿整装勘査区矿产调査与找矿预测”(121201004000160901-60) |
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| 中文摘要: |
| 德合茂岩体位于西秦岭造山带西部,岩性由花岗闪长岩和二长花岗岩组成,形成于印支期。通过岩石地球化学分析,德合茂岩体岩石具高钾钙碱性、过铝质特征,稀土总量低且呈右倾型、轻稀土LREE富集,重稀土亏损LREE/HREE比值介于11.44~14.67之间,(La)N/(Yb)N值范围为16.41~22.11,δEu=0.64~1.03,均值0.8,弱负铕异常。富集大离子亲石元素(LILE)Th、Rb、K等,相对亏损高场强元素(HFSE)P、Nb、Ta、Zr。地球化学特征指示其形成于俯冲相关的火山弧环境,岩浆源于俯冲基性岩部分熔融,并经历有限的分异结晶和地壳混染。岩体侵入与区域断裂构造密切相关,构造-岩浆活动促进了研究区铜、金等矿床成矿,具有一定的成矿潜力。 |
| 英文摘要: |
| The intrusive rocks in the Dehema area of Gansu Province are situated within the westernsegment of the West Qinling Orogenic Belt. The predominant rock types include granodiorite and syenogranite,which were formed during the Indosinian orogenic period. Geochemical analyses reveal that these intrusive rocksexhibit high-potassium calc-alkaline and peraluminous characteristics. They display relatively low total rare earthelement (REE) contents, with a right-inclined distribution pattern characterized by enrichment in light rare earthelements (LREE) and depletion in heavy rare earth elements (HREE ). The LREE/HREE ratio varies between11. 44 and 14. 67, averaging at 13. 23, while the (La)N/(Yb)N ratio ranges from 16. 41 to 22. 11, indicatingsignificant LREE enrichment and moderate fractionation. The δEu values range from 0.64 to 1. 03, with anaverage of 0.8, rellecting a weak negative Eu anomaly. These rocks are enriched in large-ion lithophile elements(LlLE), such as 'T'h, Rb, and K, and show relative depletion in high-field-strength elements (HFSE), includingP, Nb, Ta, and Zr. Based on their geochemical features, these intrusive rocks likely formed in a subductionrelated volcanic arc environment, with magmas originating from partial melting of subducted mafic rocks. Theirlimited differentiation and crustal contamination suggest a close relationship with regional fault structures.Furthermore, contaet metamorphism and hydrothermal alteration processes(e.g., silicification, skarization ) havefaeilitated the mineralization of polymetallic deposits, including copper, gold, and iron, highlighting substantiamineralization potential in this region. |
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