Evolution of the Mazatzal province and the timing of the Mazatzal orogeny: Insights from U-Pb geochronology and geochemistry of igneous and metasedimentary rocks in southern New Mexico
Evolution of the Mazatzal province and the timing of the Mazatzal orogeny: Insights from U-Pb geochronology and geochemistry of igneous and metasedimentary rocks in southern New Mexico
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DOI：
10.1130/b26200.1
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发表时间：
2008-03
影响因子：
4.9
通讯作者：
J. Amato;A. O. Boullion;Antonio M. Serna;A. E. Sanders;G. L. Farmer;G. Gehrels;J. Wooden
中科院分区：
文献类型：
--
作者：
J. Amato;A. O. Boullion;Antonio M. Serna;A. E. Sanders;G. L. Farmer;G. Gehrels;J. Wooden
本文报道了美国新墨西哥州南部古元古代Mazatzal省三个地点的锆石U-Pb年龄、地球化学和Nd同位素资料。这些数据有助于了解1680年至1620年的岩浆活动的源区和构造背景，马扎扎尔造山运动的时间，造山后岩浆活动的性质，元古代板块构造，并提供了亚利桑那州和北方新墨西哥州马扎扎尔子块之间的联系。这些数据表明，一个时期从1680年至1650年的幼年长英质花岗岩类的形成，和后来的事件之间的1646年和1633年，当这些岩石与沉积岩一起变形。没有证据前1680 Ma的岩石或继承锆石观察。岩浆岩的eNd（t）值介于-1.2 ~+4.3之间，大多数介于+2 ~+4之间，表明岩浆岩为幔源或来自同期地壳。Nd同位素和微量元素浓度与典型的弧岩浆作用模式一致。变质沉积岩的碎屑锆石年龄表明，沉积作用至少发生在1646 Ma之前。当地和Yavapai省的来源都促成了碎石。所有样本的年龄都大于ca。1650 Ma的变形，而未变形的斑晶被发现在接触晕的一个以前的1633 Ma辉长岩。在区域上，Mazatzal造山带主要发生在1654年至1643年Ma之间，在一系列岛弧和可能合并在海上的介入盆地的最终增生期间。流纹岩岩浆活动在南部Mazatzal省是同时代的辉长岩侵入体在1633马，这种双峰岩浆活动可能已与弧增生后的伸展过程。
New U-Pb zircon ages, geochemistry, and Nd isotopic data are presented from three localities in the Paleoproterozoic Mazatzal province of southern New Mexico, United States. These data help in understanding the source regions and tectonic setting of magmatism from 1680 to 1620 Ma, the timing of the Mazatzal orogeny, the nature of postorogenic magmatism, Proterozoic plate tectonics, and provide a link between Mazatzal subblocks in Arizona and northern New Mexico. The data indicate a period from 1680 to 1650 Ma in which juvenile felsic granitoids were formed, and a later event between 1646 and 1633 Ma, when these rocks were deformed together with sedimentary rocks. No evidence of pre-1680 Ma rocks or inherited zircons was observed. The igneous rocks have e Nd (t) from –1.2 to +4.3 with most between +2 and +4, suggesting a mantle source or derivation from similar-aged crust. Nd isotope and trace element concentrations are consistent with models for typical arc magmatism. Detrital zircon ages from metasedimentary rocks indicate that sedimentation occurred until at least 1646 Ma. Both local and Yavapai province sources contributed to the detritus. All of the samples older than ca. 1650 Ma are deformed, whereas undeformed porphyroblasts were found in the contact aureole of a previously dated 1633 Ma gabbro. Regionally, the Mazatzal orogeny occurred mainly between 1654 and 1643 Ma, during fi nal accretion of a series of island arcs and intervening basins that may have amalgamated offshore. Rhyolite magmatism in the southern Mazatzal province was coeval with gabbro intrusions at 1633 Ma and this bimodal magmatism may have been related to extensional processes following arc accretion.