Neoproterozoic extension and the Central Iapetus Magmatic Province in southern Mexico – New U-Pb ages, Hf-O isotopes and trace element data of zircon from the Chiapas Massif Complex
Neoproterozoic extension and the Central Iapetus Magmatic Province in southern Mexico – New U-Pb ages, Hf-O isotopes and trace element data of zircon from the Chiapas Massif Complex
复制标题
墨西哥南部新元古代伸展和中土卫八岩浆省 â 恰帕斯地块杂岩中锆石的新 U-Pb 年龄、Hf-O 同位素和微量元素数据
DOI：
10.1016/j.gr.2020.06.022
复制
发表时间：
2020
影响因子：
6.1
通讯作者：
Gerdes
中科院分区：
文献类型：
--
作者：
Schmitt;Cisneros de León;González-Guzmán;Gerdes
罗迪尼亚的最终分裂发生在埃迪卡拉纪时期，亚马逊、波罗的海和劳伦西亚漂流分开，形成了伊阿佩托斯洋。伴随着裂谷相关的基性岩墙群的中央Iapetus岩浆省（CIMP）的侵位之间的0.62和0.55 Ga，这是保存在劳伦蒂亚和波罗的海，而没有同时代的基性岩是已知的亚马逊。CIMP延伸到Oaxaquia（墨西哥Rodinia型基底）的第一个证据是在619 ± 9 Ma侵入墨西哥东北部Novillo片麻岩的拉斑玄武岩岩墙。在墨西哥东南部的恰帕斯，化学成分与Novillo岩脉相似的斜长岩和片麻岩侵入。本文提出了一种利用二次离子质谱技术，以接触变质锆石为靶点，用U单键Pb法测定基性岩墙侵入年龄的新方法。在与基性岩脉侵入接触处，温度超过700 °C（锆石中的钛测温法）时，斜长岩中结晶的锆石产生的年龄在615 ± 7 Ma和608 ± 12 Ma之间，反映了岩脉侵入的时间。锆石的化学和同位素（Hf，O）的特征表明，在奥陶纪变质过程中，涉及锆释放Fesingle键钛氧化物，其他阶段的分解和重结晶，流体减轻反应的穿时序列。Oaxaquia麻粒岩的锆石δ 18 O值范围为+6.2‰至+9.8‰，而恰帕斯东南部的Tonian（~0.92 Ga）变质锆石产生的δ 18 O值较低，为+2.0‰至+2.8‰，这是由Tonian重力塌陷期间主要构造边界的再活化所解释的。这些观测增加了CIMP在墨西哥的已知范围，表明新元古代的超级地幔柱在埃迪卡拉纪早期仍然活跃，产生了一个大的火成岩省，延伸到亚马逊河，波罗的海和劳伦特。结果进一步表明，Oaxaquia在北方边缘的亚马逊形成共轭边缘的波罗的海裂谷。
Final fragmentation of Rodinia occurred during the Ediacaran Period as Amazonia, Baltica and Laurentia drifted apart to form the Iapetus Ocean. Accompanying rift-related mafic dyke swarms of the Central Iapetus Magmatic Province (CIMP) were emplaced between 0.62 and 0.55 Ga, which are preserved in Laurentia and Baltica, whereas no coeval mafic rocks are known from Amazonia. First evidence for the CIMP extending into Oaxaquia (Rodinia-type basement of Mexico) was reported as tholeiitic dykes that intruded the Novillo gneiss, NE Mexico, at 619 ± 9 Ma. In Chiapas, SE Mexico, amphibolite dykes that are chemically similar to the Novillo dykes intruded anorthosite and gneiss. In this paper, a new dating approach to obtain mafic dyke intrusion ages is presented by targeting contact metamorphic zircon with the Usingle bondPb method, employing Secondary Ion Mass Spectrometry. Zircon that crystallized in anorthosite at intrusive contacts to mafic dykes and at temperatures exceeding 700 °C (Ti-in-zircon thermometry) yields ages between 615 ± 7 Ma and 608 ± 12 Ma, reflecting the time of dyke intrusion. Zircon chemical and isotopic (Hf, O) characteristics suggest a diachronous sequence of metamorphic processes involving Zr release from Fesingle bondTi oxides, breakdown and recrystallization of other phases, and fluid-mitigated reactions during Ordovician metamorphism. Zircon δ18O values of granulites from Oaxaquia range from +6.2‰ to +9.8‰, whereas Tonian (~0.92 Ga) metamorphic zircon from SE Chiapas yielded low δ18O values from +2.0‰ to +2.8‰ that are explained by the reactivation of major tectonic boundaries during Tonian gravitational collapse. The observations increase the known extent of the CIMP in Mexico, suggesting that a Neoproterozoic superplume was still active during the Early Ediacaran producing a Large Igneous Province that extended over Amazonia, Baltica and Laurentia. The results further suggest that Oaxaquia at the northern edge of Amazonia formed the conjugate margin of Baltica during rifting.
登录
查看更多内容
616 Ma老埃格尔松玄武岩墙群，挪威西南部，与新元古代晚期土卫八洋的张开
DOI：
--
发表时间：
1998
期刊：
The Journal of geology
影响因子：
--
作者：
B. Bingen;D. Demaiffe;O. Breemen
通讯作者：
O. Breemen
墨西哥恰帕斯州格伦维尔地块型斜长岩套：斜长岩及其钛铁矿石的岩浆到多变质演化
DOI：
--
发表时间：
2017
期刊：
影响因子：
--
作者：
A. C. D. León;B. Weber;F. Ortega;Reneé González;R. Maldonado;L. Solari;P. Schaaf;Román Manjarrez
通讯作者：
Román Manjarrez
影响因子：
1.8
作者：
J. Keppie;F. Ortega-Gutiérrez
通讯作者：
J. Keppie;F. Ortega-Gutiérrez
608 Ma 巨神海洋海底开始扩张：瑞典喀里多尼德北部 Sarek Dyke Swarm 的精确年龄
DOI：
--
发表时间：
2001
期刊：
影响因子：
--
作者：
O. Svenningsen
通讯作者：
O. Svenningsen
元古代哥伦比亚与墨西哥南部联系的铅同位素证据
影响因子：
2.6
作者：
J. Ruíz;R. Tosdal;P. Restrepo;G. Murillo
通讯作者：
G. Murillo