Edge-driven convection melting before the emplacement of the Afar mantle plume head inferred from 40Ar/39Ar dating
Edge-driven convection melting before the emplacement of the Afar mantle plume head inferred from 40Ar/39Ar dating
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根据 40Ar/39Ar 测年推断阿法尔地幔柱头部就位之前的边缘驱动对流熔融
DOI：
10.1029/2022gl102560
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发表时间：
2023
影响因子：
5.2
通讯作者：
Otofuji Yo‐ichiro
中科院分区：
文献类型：
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作者：
Yoshimura Yutaka;Ishizuka Osamu;Yamazaki Toshitsugu;Ahn Hyeon‐Seon;Kidane Tesfaye;Yamamoto Yuhji;Sekimoto Shun;Sano Takashi;Otofuji Yo‐ichiro
埃塞俄比亚-也门洪水玄武岩的空间分区与逐渐降低TiO 2熔岩从阿法尔凹陷附近的边缘。与超高TiO 2（HT 2）熔岩相比，低TiO 2（LT）熔岩的侵位时间和速率知之甚少。我们测量了阿法尔地幔柱头边缘2 km厚LT熔岩序列玄武岩的两个高精度40 Ar/39 Ar年龄，分别为29.63 ± 0.14和30.02 ± 0.22 Ma（2σ）。利用我们的喷发年龄模型，根据我们和以前的40 Ar/39 Ar年龄与古地磁方向，我们估计LT熔岩喷发持续超过Chrons C12 r-C12 n-C11 r。地幔柱头边缘的喷发开始早于地幔柱头轴的侵位。此外，喷发率在边缘低，在轴高。我们估计，LT熔岩是由边缘驱动的对流引起的，是地幔柱-岩石圈相互作用的结果，而不是地幔柱头。
The Ethiopia‐Yemen flood basalts are spatially zoned with progressively lower TiO2lavas from near the Afar depression toward the margins. The timing and rate of emplacement of low TiO2(LT) lavas are poorly known compared with the ultra‐high TiO2(HT2) lavas. We measured two high‐precision40Ar/39Ar ages of 29.63 ± 0.14 and 30.02 ± 0.22 Ma (2σ) from basalts of the 2‐km‐thick LT lava sequence at the Afar plume head margin. Using our eruption age model constructed from our and previous40Ar/39Ar ages with the paleomagnetic directions, we estimate that the LT lava eruption continued over Chrons C12r‐C12n‐C11r. The eruption of the plume head margin started earlier than the plume head axis emplacement in C12n. Also, the eruption rate was low at the margin, high at the axis. We estimate that the LT lavas are induced by the edge‐driven convection, the result of a plume‐lithosphere interaction, not a plume head.