Structure of the accretionary prism, and the evolution of the Paleogene northern Caribbean subduction zone in the region of Camagüey, Cuba
Structure of the accretionary prism, and the evolution of the Paleogene northern Caribbean subduction zone in the region of Camagüey, Cuba
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DOI：
10.1016/j.jsg.2009.06.007
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发表时间：
2009-10
影响因子：
3.1
通讯作者：
D. Hinsbergen;M. Iturralde-Vinent;P. V. Geffen;A. Garcia‐Casco;S. V. Benthem
中科院分区：
文献类型：
--
作者：
D. Hinsbergen;M. Iturralde-Vinent;P. V. Geffen;A. Garcia‐Casco;S. V. Benthem
在古新世至始新世中晚期，北古巴褶皱冲断带中沉积单元的变形历史与加勒比和北美板块之间的主要缩短有关。这导致形成了一个强烈变形的构造堆，从上到下包括一个火山弧推覆体，一个变形的镁铁质-超镁铁质杂岩，其中有中生代蛇绿岩成分和一个蛇纹质混杂岩，其中有沉积岩块（Placetas带）和变质岩;以及由巴哈马地台南部海角的褶皱和逆冲沉积物组成的结构下部单元。在本文中，我们研究的变形历史的沉积单元纳入北古巴褶皱冲断带与此缩短的历史。我们发现，在片理化蛇纹岩混杂岩中的Placetas沉积岩的产状表现出不同的变形方式和强度，以及不同数量的变形阶段。它们在蛇纹岩混杂岩中形成孤立的岩块，并不代表异源镁铁质-超镁铁质杂岩下的连贯推覆体。作为巴哈马地台一部分的雷梅迪奥斯带的变形经历了单一的褶皱和逆冲阶段，垂直于板块接触面缩短。这种褶皱作用发生在始新世中晚期，标志着俯冲和弧-陆碰撞的停止。我们没有发现证据的一个组成部分，在碰撞走滑。火山弧逆冲于镁铁质-超镁铁质杂岩之上，原弧前蛇绿岩缩短。这种缩短可能证明了一段时期的俯冲侵蚀。火山弧的逆冲作用导致了古新世-下始新世塔瓜斯科堆积层的沉积，这可能是该事件的日期。我们表明，仔细分析的复杂变形的古巴褶皱和冲断带可能允许识别俯冲侵蚀和俯冲增生情节。将本文的分析扩展到北方加勒比褶皱冲断带的尺度，可能会提供一种新的独立的地质工具来约束与沿着北方加勒比边缘的俯冲和弧-大陆碰撞相关的地球动力学过程。
The deformation history of sedimentary units incorporated in the North Cuban fold and thrust belt in the Paleocene to middle–late Eocene was associated with major shortening between the Caribbean and North American plates. This led to the formation of an intensely deformed tectonic pile comprising from top to bottom of a volcanic arc nappe, a deformed mafic–ultramafic complex with Mesozoic ophiolite components and a serpentinitic me´lange with blocks of sedimentary (the Placetas belt) and metamorphic rocks; and the structurally lower unit composed of folded and thrusted sediments of the southern promontory of the Bahamas platform. In this paper we study the deformation history of sedimentary units incorporated in the North Cuban fold and thrust belt associated with this shortening history. We find that the occurrences of the Placetas sedimentary rocks within the foliated serpentinite mélange show varying styles and intensity of deformation, and varying number of deformation phases. They form isolated blocks within the serpentinite mélange and do not represent a coherent nappe underlying the allochtonous mafic–ultramafic complex. The deformation of the Remedios belt, part of the Bahamas platform, underwent a single phase of folding and thrusting, with shortening perpendicular to the plate contact. This folding occurred in the middle to late Eocene and marks the arrest of subduction and arc–continent collision. We find no evidence for a component of strike-slip during collision. The volcanic arc is thrusted upon the mafic–ultramafic complex, and the original forearc ophiolite appears to be shortened. This shortening may attest to a period of subduction erosion. Thrusting of the volcanic arc led to deposition of the Paleocene-lower Eocene Taguasco olistostrome which may date this event. We show that careful analysis of the complexly deformed Cuban fold and thrust belt may allow identification of subduction erosion and subduction accretion episodes. Expanding the analysis carried out in this paper to the scale of the northern Caribbean fold and thrust belt may provide a new and independent geological tool to constrain the geodynamic processes associated with subduction and arc–continent collision along the northern Caribbean margin.