Recycling in the subduction factory: Archaean to Permian zircons in the oceanic Cretaceous Caribbean island-arc (Hispaniola)
Recycling in the subduction factory: Archaean to Permian zircons in the oceanic Cretaceous Caribbean island-arc (Hispaniola)
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DOI：
10.1016/j.gr.2017.09.010
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发表时间：
2018-02
影响因子：
6.1
通讯作者：
L. Torró;J. Proenza;Y. Rojas‐Agramonte;A. Garcia‐Casco;Jin-Hui Yang;Yue-heng Yang
中科院分区：
文献类型：
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作者：
L. Torró;J. Proenza;Y. Rojas‐Agramonte;A. Garcia‐Casco;Jin-Hui Yang;Yue-heng Yang
很少有矿物学证据表明大陆和海洋地壳在俯冲带再循环进入地幔。锆石，由于其特殊的鲁棒性，可能是唯一幸存的阶段和最好的矿物示踪剂，这一全球规模的过程。本文结合新的原位U-Pb定年和O和Hf同位素分析的白垩纪（同岩浆）和前白垩纪（继承）从阿尔比安Aptian弧有关的火成岩从多米尼加共和国分离的锆石。白垩纪锆石的O和Hf系统学反映了主要来自幼年源和与演化熔体的变量混合的衍生，正如预期的大洋岛弧。继承锆石U-Pb年龄在256 ~ 2923 Ma之间（n = 219）。大多数研究的继承锆石是二叠纪-石炭纪，峰值约。从矿物包裹体（石英、正长石、白云母、磷灰石）、δ 18 O（6.16 ~ 12.67‰）和εHf（t）（− 11.9 ~ 1.12）值判断，该矿床形成于陆壳中。奥陶纪至元古代的锆石δ 18 O在4.93 ‰至9.21‰之间，εHf（t）在− 19.9至8.5之间，因此与幔源（幼年）岩浆或来自表壳岩熔融的岩浆平衡结晶。太古代锆石δ 18 O介于6.98 ~ 7.94‰之间，εHf（t）介于− 18.5 ~ − 1.6之间，可能反映了母岩浆中表壳物质的贡献。我们认为，弧岩浆拿起继承锆石货物从他们的地幔来源。会计古地理和古构造的限制，墨西哥和哥伦比亚的锆石被确定为潜在的主要（岩浆）和次要（沉积）来源的研究继承锆石。我们设想，继承的锆石被向下运送到地幔下的加勒比板块的碎屑颗粒俯冲的原始加勒比和/或太平洋板块的顶部。
Little mineralogical evidence is left of the recycling of continental and oceanic crust into the mantle at subduction zones. Zircon, because of its exceptional robustness, is probably the only surviving phase and the best mineral tracer of this global-scale process. This article combines new in-situ U-Pb dating and O and Hf isotope analyses on Cretaceous (co-magmatic) and pre-Cretaceous (inherited) zircons separated from Albian-Aptian arc-related igneous rocks from the Dominican Republic. The O and Hf systematics of Cretaceous zircons reflect derivation from predominantly juvenile sources and variable mixing with evolved melts, as expected for an oceanic island-arc. Inherited zircons yield U-Pb ages between 256 and 2923 Ma (n = 219). Most studied inherited zircons are Permian-Carboniferous, peaking at ca. 300 Ma, and formed in continental crust to judge from mineral inclusions (including quartz, orthoclase, muscovite and apatite), δ18O (6.16 to 12.67‰) and εHf(t) (− 11.9 to 1.12) values. Ordovician to Proterozoic zircons yield δ18O between 4.93 and 9.21‰ and εHf(t) between − 19.9 and 8.5 and hence crystallized in equilibrium with either mantle-derived (juvenile) magmas or magmas derived from melting of supracrustal rocks. For Archean zircons, δ18O between 6.98 and 7.94‰ and εHf(t) between − 18.5 and − 1.6 might reflect contribution of supracrustal materials in the parent magmas. We suggest that arc magmas picked up the inherited zircon cargo from their mantle sources. Accounting paleogeographic and paleo-tectonic constraints, Mexican and Colombian terranes are identified as the potential primary (magmatic) and secondary (sedimentary) sources for the studied inherited zircons. We envisage that inherited zircons were transported downward to the mantle beneath the Caribbean plate as detrital grains on top of the subducting Proto-Caribbean and/or Pacific slabs.