The Costa Rican Jurassic to Miocene oceanic complexes: Origin, tectonics and relations
The Costa Rican Jurassic to Miocene oceanic complexes: Origin, tectonics and relations
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DOI：
10.1016/j.jsames.2009.04.010
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发表时间：
2009-12-01
影响因子：
1.8
通讯作者：
Gazel, Esteban
中科院分区：
文献类型：
--
作者：
Denyer, Percy;Gazel, Esteban
哥斯达黎加太平洋沿岸的海洋组合是具有不同构造起源的复杂建筑群的一部分。虽然它们被肢解和破坏，但它们是唯一可用的内陆信息来源，可以破译这一活动边缘的演变。本文描述了六个主要区域:(1)圣埃琳娜半岛，由一个超俯冲带（圣埃琳娜推覆体）构成，它逆冲了一个包括OIB（洋岛玄武岩）部分的阿普提亚-塞诺曼尼亚火成岩-沉积序列（圣罗莎增生杂岩）；(2)尼科亚杂岩，它是一个侏罗纪-白垩纪燧石沉积堆，在CLIP（加勒比大火成岩省）形成期间发生的多次岩浆事件破坏并脱离了原来的基底；(3)具有OIB特征的Tortugal套形成的Tortugal区，周围为Nicoya杂岩露头；(4)由Tulin组至Maastrichtian至下始新统OIB沉积的洋岛和Nicoya杂岩组成的Herradura地块为基底；(5)与Tulin组相关的Quepos地块；(6)由Golfito和Burica地体组成的Osa-Burica地块（地球化学和年代学上与Nicoya杂岩相关）；Rincon地块（早古新世至早始新世增生海山）和中新世Osa-Cano增生杂岩。Santa Rosa增生杂岩和Tortugal套件具有OIB特征，可能没有Galapagos热点地球化学亲和力。这些巧合可以用“本地”白垩纪基底的假设存在来解释，该基底是由这两个地区与加勒比海其他地区共同形成的。哥斯达黎加基底由西北白垩纪末至东南中新世增生的多个CLIP部分和海山组成，形成了太平洋多样的海洋产状，主要与Galapagos热点活动有关。2009爱思唯尔有限公司版权所有。
The occurrences of oceanic assemblages on the Pacific shore of Costa Rica are part of an intricate group of complexes with different tectonic origins. Although they are dismembered and disrupted, they are the only available inland source of information to decipher the evolution of this active margin. Six main regions are described in this paper: (1) Santa Elena Peninsula, constituted by a supra-subduction zone (Santa Elena Nappe), that is overthrusting an igneous-sedimentary Aptian-Cenomanian sequence (Santa Rosa Accretionary Complex), which includes OIB (Ocean Island Basalts) portions, (2) the Nicoya Complex, which is a Jurassic-Cretaceous chert sediment pile disrupted and detached from its original basement by multiple magmatic events that occurred during the formation of the CLIP (Caribbean Large Igneous Province), (3) the Tortugal area formed by the Tortugal Suite with OIB signature and surrounded by Nicoya Complex outcrops, (4) the Herradura Block composed of the Tulin Formation to Maastrichtian to Lower Eocene OIB accreted oceanic island and the Nicoya Complex as basement, (5) Quepos Block correlated with the Tulin Formation, (6) the Osa-Burica Block composed of the Golfito and Burica Terranes (geochemically and chronologically correlated to the Nicoya Complex), Rincon Block (Early Paleocene to Early Eocene accreted seamounts), and the Miocene Osa-Cano Accretionary Complex. The Santa Rosa Accretionary Complex together with the Tortugal Suite have OIB signatures and possibly without Galapagos hotspot geochemical affinity. These coincidences would be explained by the hypothetical existence of an "autochthonous" Cretaceous basement formed by these two regions together with the rest of the Caribbean. Costa Rican basement is constituted by several CLIP portions and seamounts accreted from the end of Cretaceous in the northwest to the Miocene in the southeast, forming the diverse oceanic occurrences of the Pacific, which are mainly connected to the Galapagos hotspot activity. (C) 2009 Elsevier Ltd. All rights reserved.