Breaking Up Is Hard to Do: Magmatism During Oceanic Arc Breakup, Subduction Reversal, and Cessation
Breaking Up Is Hard to Do: Magmatism During Oceanic Arc Breakup, Subduction Reversal, and Cessation
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DOI：
10.1029/2022gc010663
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发表时间：
2022-11
期刊：
影响因子：
3.7
通讯作者：
J. Gill;E. Todd;K. Hoernle;F. Hauff;A. Price;M. Jackson
中科院分区：
文献类型：
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作者：
J. Gill;E. Todd;K. Hoernle;F. Hauff;A. Price;M. Jackson
在中新世俯冲极性逆转期间，原先连续的维蒂亚兹弧断裂成瓦努阿图和斐济部分。斐济的玄武岩火山活动伴随着断裂，范围从钾玄岩到低钾和玻安岩，随着距离弧的断裂边缘的距离增加，据推测，标志着板片的断裂边缘。断裂玄武岩中板片衍生组分的Sr-Pb-Nd同位素比最接近于太平洋板块上萨摩亚海山链同位素最贫化部分的同位素比，该部分邻近4-8 Ma断裂的地点，并且与周围弧后北斐济和劳盆地扩张段中后续玄武岩的同位素比不同。萨摩亚岛链沿着维蒂亚兹海沟线性构造的俯冲可能控制了极性反转的极限，因此，也控制了双轿车门的开启位置（马丁，2013年）。在断裂之前，斐济火山岩的同位素与路易斯维尔海山链更为相似。
The formerly continuous Vitiaz Arc broke into its Vanuatu and Fijian portions during a reversal of subduction polarity in the Miocene. Basaltic volcanism in Fiji that accompanied the breakup ranged from shoshonitic to low‐K and boninitic with increasing distance from the broken edge of the arc that, presumably, marks the broken edge of the slab. The Sr‐Pb‐Nd isotope ratios of the slab‐derived component in the breakup basalts most closely match those of the isotopically most depleted part of the Samoan seamount chain on the Pacific Plate that was adjacent to the site of breakup at 4–8 Ma, and differ from those of subsequent basalts in spreading segments of the surrounding backarc North Fiji and Lau Basins. Subduction of the Samoan Chain along the Vitiaz Trench Lineament may have controlled the limit of polarity reversal and, hence, where the double saloon doors (Martin, 2013) opened. Prior to breakup, Fijian volcanics were more similar isotopically to the Louisville Seamount Chain.