Volcanic and tectonic features of Shirahama Bank in the northern Ryukyu Arc: Implications for cross-arc volcanism controlled by arc-parallel extension
Volcanic and tectonic features of Shirahama Bank in the northern Ryukyu Arc: Implications for cross-arc volcanism controlled by arc-parallel extension
复制标题
琉球弧北部白滨浅滩的火山和构造特征：弧平行伸展控制的跨弧火山活动的意义
DOI：
10.1016/j.margeo.2021.106623
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发表时间：
2021
期刊：
影响因子：
2.9
通讯作者：
Hiroko Tendo
中科院分区：
文献类型：
--
作者：
H. Minami;Y. Ohara;Hiroko Tendo
白滨滩是位于琉球弧北方的一个未被勘探过的浅海底构造体，其火山作用和构造作用的性质一直以来都没有得到很好的认识。新的高分辨率（5米）水深测量显示，白滨滩在其平顶上有小的火山大厦和洼地，水深为60-150米。这些建筑物有尖的山顶，坡度大于30°。在凹陷内，共59声气泡羽被船载多波束声纳检测到，这表明活跃的火山脱气发生在这个地区。河岸完全被NW-SE至WNW-ESE走向的线性构造分割，而平顶上的火山大厦和洼地未被分割。白滨滩是由多期火山作用形成的。最年轻的火山阶段可能发生在晚更新世期间海平面低位的地表侵蚀和构造变形之后，为北方琉球弧第四纪火山活动的时间提供了限制。观察到该地区弧火山作用的构造控制。在白滨滩及其周围确定的NW-SE至WNW-ESE线性构造被解释为正断层，并形成跨弧地堑构造。白滨滩及周边地区的年轻火山构造和活跃的气泡羽流集中在这些跨弧地堑内，表明琉球弧北方的最新火山活动受~NE-SW向伸展（弧平行或沿弧伸展）的控制。我们的研究结果，结合以往的研究表明，弧平行伸展，这不同于以前已知的弧后伸展在冲绳海槽，在弧火山作用的初始阶段起着重要的作用。
This paper presents volcanic and tectonic features of Shirahama Bank, an unexplored shallow submarine edifice in the northern Ryukyu Arc which was previously poorly mapped, and consequently the nature of its volcanism and tectonism have been poorly understood. New high-resolution (5 m) bathymetry revealed that Shirahama Bank has small volcanic edifices and depressions on its flat top with water depths of 60–150 m. The edifices have pointy summits with steep slopes greater than 30°. Within the depressions, a total of 59 acoustic bubble plumes were detected by shipboard multibeam sonar, suggesting that active volcanic degassing occurs in this region. The bank is dissected entirely by NW–SE to WNW–ESE trending lineaments while the volcanic edifices and depressions on the flat top are undissected. Shirahama Bank was formed by multiple-stages of volcanism. The youngest volcanic stage probably occurred after surface erosion by sea-level low-stand during the late Pleistocene and after tectonic deformation, providing a constraint on the timing of Quaternary volcanism in the northern Ryukyu Arc. Structural control of arc volcanism in the area is observed. The NW–SE to WNW–ESE lineaments identified on and around Shirahama Bank are interpreted as normal faults and form cross-arc graben structures. The young volcanic structures and active bubble plumes at Shirahama Bank and surrounding areas are concentrated within these cross-arc grabens, suggesting that the most recent volcanism is controlled by ~NE–SW extension (arc-parallel or along-arc extension) in the northern Ryukyu Arc. Our results, combined with previous studies, suggest that arc-parallel extension, which differs from the previously known back-arc extension in the Okinawa Trough, plays an important role in arc volcanism during its initial stages.
BRAVOSEIS：南极洲布兰斯菲尔德海峡裂谷和火山活动的地球物理调查
影响因子：
1.8
作者：
Alemendros, J.;Wilcock, W.S.D.;Soule, D.;Teixido, T.;Vizcaino, L.;Ardazaz, O.;Granja-Bruña, J. L.;Martin-Jimenez, D.;Yuan, X.;Heit, B.
通讯作者：
Heit, B.