Seamount‐Volcanic Island Transition and Evolution From Fissural to Central Activity Inferred by the Magnetic Modeling of Salina Island (Tyrrhenian Sea)
Seamount‐Volcanic Island Transition and Evolution From Fissural to Central Activity Inferred by the Magnetic Modeling of Salina Island (Tyrrhenian Sea)
复制标题
萨利纳岛（第勒尼安海）磁力模拟推断海山-火山岛从裂隙到中心活动的转变和演化
DOI：
10.1029/2018jb017113
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Guido Ventura
中科院分区：
文献类型：
--
作者：
L. Cocchi;R. De Ritis;D. Casalbore;C. Romagnoli;F. Lucchi;C. Tranne;Guido Ventura
火山岛代表了早期海底火山活动的后期阶段，并表现出不同的形态，反映了浅层管道系统的几何形状、岩浆输出率、重力不稳定和侵蚀阶段。可以识别两种端元形态：（a）裂谷状细长建筑物和“星状”火山和（b）锥形中央型火山。虽然从早期圆锥形到星形的演变相对众所周知，但相反的情况则较少受到限制，通常缺乏地球物理和地质数据来支持。我们提出了萨利纳火山岛（244-15 ka；风神弧，南第勒尼安海）的磁正向和 3-D 反演模型，以表征其浅层管道系统。检测到的磁源被解释为堤坝和垂直管道的结晶部分。堤坝主要是萨利纳岛近海的特征，而次圆形导管则位于岸上。结果表明，萨利纳的早期主要是海底阶段集中在具有构造意义的薄弱带之后的岩脉上。随着火山活动的进行，地面活动集中在两个主要的锥形成层火山（Monte Fossa delle Felci 和 Monte dei Porri）。在盐沼早期生长过程中，岩脉之间的交叉和火山产物的逐渐加载导致了从早期裂隙玄武岩活动到后来的玄武岩活动到最后的、更进化的中心型火山活动的转变。我们得出的结论是，沿着预先存在的构造结构、岩脉交叉点和与火山堆形成相关的加载过程的侵入调节了火山岛从早期海底阶段到后期地面活动的形态和结构演化。
Volcanic islands represent the later stage of an early submarine volcanic activity and show different morphologies reflecting the geometry of shallow plumbing systems, magma output rate, gravitational instability, and erosive phases. Two end‐member morphologies may be recognized: (a) rift‐like elongated edifices and ‘stellate’ volcanoes and (b) cone‐shaped, central‐type volcanoes. While the evolution from early conical shapes to stellate shapes is relatively well known, the reverse is less constrained, commonly lacking geophysical and geological data to support it. We present magnetic forward and 3‐D inverse models of the volcanic island of Salina (244‐15 ka; Aeolian Arc, Southern Tyrrhenian Sea) to characterize its shallow plumbing system. The detected magnetic sources are interpreted as the crystallized portions of dykes and vertical conduits. The dykes mainly characterize the offshore of Salina Island, whereas subcircular conduits are located onshore. The results show that the early, mainly submarine phases of Salina concentrated along dykes following weakness zones of tectonic significance. As the volcanism proceeded, the subaerial activity focused on two main cone‐shaped stratovolcanoes (Monte Fossa delle Felci and Monte dei Porri). The intersections among dykes and the progressive loading of volcanic products during the early growth of Salina are responsible for the transition from an early fissural basaltic activity to a later, basaltic to a last, more evolved central‐type volcanism. We conclude that intrusions along pre‐existing tectonic structures, dyke intersections, and loading processes related to the formation of a volcanic pile regulate the morphology and structural evolution of volcanic islands from the early, submarine phase to the later subaerial activity.