Early Cretaceous Mineralizations in Ningwu Basin: Insight from Actinolite ³⁹Ar-⁴⁰Ar Laser Dating Results

• 责任者：Ma Fang (Key Laboratory of Orogenic Belts and Crustal Evolution ; Ministry of Education ; School of Earth and Space Sciences ; Peking University ; Beijing 100871 ; China) ; Jiang Shaoyong
• 刊名：Mineral Deposits
• 出版年：2010
• 卷期：29(2)
• 关键词：玢岩铁矿床 ; porphyrite iron deposit ; Ar-40／Ar-39 ; 氩—氩计时 ; Ar-Ar dating ; 江苏 ; Jiangsu Province ; 安徽 ; Anhui Province
• 页码：p.283-289
• 图表：2 illus., 1 table, 19 refs.
• 分类号：1001
• issnNo：ISSN0258-7106
• isbnNo：CN11-1965/P

Actinolite ³⁹Ar-⁴⁰Ar laser fusion technique was employed to determine the metallogenic epochs of the Ningwu porphyrite iron deposits. The ³⁹Ar-⁴⁰Ar isochron ages of the fresh actinolite (dark green) from the Dongshan iron deposit are from 126 to 129 Ma, which agree with the ³⁹Ar-⁴⁰Ar isochron age (127 Ma) of hornblende from the host volcanic rock of Dawangshan Group within the analytical errors, indicating that iron mineralization was associated with the Dawangshan Group volcanic rocks. The ³⁹Ar-⁴⁰Ar spectrum ages of altered actinolite (gray green) from the Washan iron deposit is (114±16) Ma. The two kinds of actinolites were formed at different metallization stages.