Age of the Batoka basalts, northern Zimbabwe, and the duration of Karoo Large Igneous Province magmatism
Age of the Batoka basalts, northern Zimbabwe, and the duration of Karoo Large Igneous Province magmatism
复制标题
津巴布韦北部巴托卡玄武岩的年龄和卡鲁大火成岩省岩浆作用的持续时间
DOI：
10.1029/2000gc000110
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发表时间：
2001
期刊：
影响因子：
3.7
通讯作者：
C. MacNiocaill
中科院分区：
文献类型：
--
作者：
D. L. Jones;Robert A. Duncan;J. Briden;D. E. Randall;C. MacNiocaill
对维多利亚瀑布以东约40公里的赞比西河峡谷中暴露的Batoka玄武岩的分析表明，它们是高铁、中等高钛、低钾、磷和锆的拉斑岩。40Ar - 39Ar的年龄测定集中在180-179 Ma。所取样的火山岩均具有正常的古磁极，对应的磁极位置为63.9°N, 260.6°E, A95 = 14.9°。在南非、莱索托和纳米比亚，绝大多数Karoo玄武岩在183±1 Ma时被挤压，有些甚至在179 Ma时被挤压[Duncan et al., 1997]。津巴布韦和Lebombo之间的~ 179 Ma岩石的古地磁和地球化学对比支持了年龄差异是真实存在的结论，从而证实了Karoo大火成岩省就位期间的~ 5 Myr的估计。
Analysis of the Batoka Basalts exposed in the Zambezi Gorge some 40 km east of Victoria Falls characterizes them as high Fe, moderately high Ti, and low K, P, and Zr tholeiites. The 40Ar‐39Ar age determinations are tightly clustered at 180–179 Ma. All of the lavas that were sampled have normal paleomagnetic polarity, and the corresponding pole position is 63.9°N, 260.6°E, A95 = 14.9°. In South Africa, Lesotho, and Namibia the vast majority of Karoo basalts were extruded at 183 ± 1 Ma with some as young as 179 Ma [Duncan et al., 1997]. Paleomagnetic and geochemical correlation of the ∼179 Ma rocks between Zimbabwe and Lebombo supports the conclusion that the age difference is real and hence confirms the estimate of ∼5 Myr for the duration of emplacement of the Karoo Large Igneous Province.