Shallow structure and active tectonism of an offshore continental back-arc spreading system: the Taupo Volcanic Zone, New Zealand
Shallow structure and active tectonism of an offshore continental back-arc spreading system: the Taupo Volcanic Zone, New Zealand
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近海大陆弧后扩张系统的浅层结构和活动构造：新西兰陶波火山带
DOI：
10.1016/0025-3227(92)90021-9
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
I. Wright
中科院分区：
文献类型：
--
作者：
I. Wright
陶波火山带（TVZ）是新西兰次大陆内主要的活火山构造结构，标志着与希库兰吉板块边界边缘的太平洋和澳大利亚板块会聚相关的第四纪弧后扩张和钙碱性火山活动带，新西兰北岛。新的测深，浅层地震反射，磁异常，格洛丽亚数据在这里首次准确地定义了TVZ的鲜为人知的海上部分的范围，结构和构造。这些数据显示，近一半的人。40 km宽的TVZ位于海上，向东北方向延伸约150 km，到达36°45′S。海上TVZ的东南和西北边界具有重要的构造和水深特征，包括向内的正断层带（分别为白色岛和陶朗加断层带）。沿沿着海上TVZ的长度确定了三个基本平行的构造形态单元。它们由东南向西北包括一个正面的非火山地堑、一个火山脊和一个火山“弧后”地堑。这些单元相对于希库兰吉俯冲边缘的空间位置不是简单的“弧”和“弧后”关系。在近海TVZ内的构造作用，虽然普遍，从西北向东南增加，使最高的延伸和沉降的非火山地堑的区域发生在火山脊的前面。地球物理数据还表明，弧前腹地的块体可能沿沿着其东南边缘构造消融到离岸TVZ中。南部的Havre海槽和北方TVZ向左偏移45-50 km。它们重叠了40公里，在方向上相差约40公里。七度。这两种伸展状态之间的右旋位移由一系列右旋斜向梯形“书架”断层提供。海上TVZ内的伸展构造的方向也是右旋的，与边界断层的区域030°走向成10°-15°，并且与根据大地测量和地震学数据确定的最大伸展轴一致。
The Taupo Volcanic Zone (TVZ), the predominant active volcano-tectonic structure within the New Zealand sub-continent, marks the zone of Quaternary back-arc spreading and calc-alkaline volcanism associated with the convergence of the Pacific and Australian plates at the Hikurangi plate-boundary margin, North Island, New Zealand. New bathymetric, shallow seismic reflection, magnetic anomaly, and GLORIA data presented here accurately define for the first time the extent, structure and tectonism of the poorly known offshore portion of the TVZ. These data show that nearly half of the entire ca. 40 km wide TVZ lies offshore, extending northeast for some 150 km seaward to 36°45′S.The southeastern and northwestern boundaries of the offshore TVZ are significant tectonic and bathymetric features, which comprise inward facing normal fault zone (the White Island and Tauranga Fault Zones, respectively). Three, essentially parallel, tectono-morphological units are identified along the length of the offshore TVZ. They comprise (from southeast to northwest) a frontal non-volcanic graben, a volcanic ridge, and a volcanic “back-arc” graben. The spatial position of these units with respect to the Hikurangi subduction margin is not a simple “arc” and “back-arc” relationship. Tectonism within the offshore TVZ, although pervasive, increases from northwest to southeast, so that the area of highest extension and subsidence of the non-volcanic graben occurs in front of the volcanic ridge. Geophysical data also suggest the possible tectonic ablation of blocks of the forearc hinterland into the offshore TVZ along its southeastern margin.The southern Havre Trough and northern TVZ are offset sinistrally by 45–50 km. They overlap by 40 km, and differ in orientation by ca. 7°. Dextral displacement between these two extensional regimes is accomodated by a series of dextrally oblique anden-échelon“bookshelf” faults. The orientation of extensional structures within the offshore TVZ is also dextrally oblique, by 10°–15° to the regional 030° trend of the bounding faults, and agree with axes of maximum extension determined elsewhere from geodetic and seismological data.