Dating the initiation of Piemonte-Liguria Ocean subduction: Lu–Hf garnet chronometry of eclogites from the Theodul Glacier Unit (Zermatt-Saas zone, Switzerland)
Dating the initiation of Piemonte-Liguria Ocean subduction: Lu–Hf garnet chronometry of eclogites from the Theodul Glacier Unit (Zermatt-Saas zone, Switzerland)
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确定皮埃蒙特-利古里亚大洋俯冲起始的年代：Theodul 冰川单元（瑞士采尔马特-萨斯地区）榴辉岩的 LuâHf 石榴石测时法
DOI：
10.1007/s00015-015-0180-5
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发表时间：
2015
影响因子：
3.1
通讯作者：
Bucher
中科院分区：
文献类型：
--
作者：
Sandmann;Miladinova;Fonseca;Froitzheim;Münker;Bucher
阿尔卑斯山脉中西部的奔尼尼克推覆体是在早第三纪奔尼尼克洋闭合后的碰撞带环境中形成的。本研究报告了采自Theodul冰川单元的两个榴辉岩样品的Lu-Hf石榴石全岩年龄分别为56.5 ± 2.7和58.2 ± 1.4 Ma。Theodul冰川单元位于蛇绿岩Zermart-Saas带的结构最上部。石榴石中主要元素Mn、Y和Lu的分布，特别是岩心中Lu的富集，表明年龄记录了压力增加过程中石榴石的快速生长。它们为“古新世恢复阶段”俯冲的继续提供了直接证据，这一阶段通常被认为是一个构造静止期，因为碎屑沉积物沉积减少，缺乏褶皱和逆冲断层，以及大西洋磁异常模式导致的非洲-欧洲会聚停止。在没有非洲-欧洲会聚的情况下，正在进行的俯冲的证据表明，俯冲系统是由作用在下行板片上的重力驱动的，并且俯冲是通过上板的延伸来平衡的。Theodul冰川单元两个样品Lu-Hf年龄的重叠表明，该构造单元代表了一个连贯体。Zermart-Saas带的另一个元素Lago di Lagnana单元的48 Ma Lu-Hf年龄的差异表明，Zermart-Saas带由构造亚单元组成，这些亚单元在大约10 Ma的长时间内达到各自的压力峰值。
The Penninic nappe stack in the Central and Western Alps was formed in a collision zone environment after the closure of the Penninic oceans in the Paleogene. This study reports Lu–Hf garnet-whole rock ages of 56.5 ± 2.7 and 58.2 ± 1.4 Ma for two eclogite samples from the Theodul Glacier Unit, which is inserted within the structurally uppermost parts of the ophiolitic Zermatt-Saas Zone. The distribution of major elements, Mn, Y, and Lu in garnet, and specifically an enrichment of Lu in the cores, indicate that the ages record prograde growth of garnet during pressure increase. They provide direct evidence for the continuation of subduction during the “Paleocene restoration phase”, often regarded as a tectonically quiescent period due to a reduction in clastic sediment deposition, lack of folds and thrusts of this age, and a cessation of Africa–Europe convergence as derived from the magnetic anomaly pattern in the Atlantic Ocean. The evidence for ongoing subduction in the absence of Africa–Europe convergence suggests that the subduction system was driven by gravity acting on the downgoing slab in a rollback setting, and that subduction was balanced by extension of the upper plate. The overlap of the Lu–Hf ages of both samples from the Theodul Glacier Unit show that this tectonic element represents a coherent body. The difference with respect to the 48 Ma Lu–Hf age of the Lago di Cignana Unit, another element of the Zermatt-Saas Zone, shows that the Zermatt-Saas Zone consists of tectonic subunits, which reached their respective pressure peaks over a prolonged period of approximately 10 Ma.
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东阿尔卑斯山 Tauern Window 变质作用的时间：Rb-Sr 年龄和织物形成
影响因子：
3.4
作者：
S. Inger;R. Cliff
通讯作者：
R. Cliff
采尔马特-萨斯蛇绿岩中榴辉岩化年龄的 Sm-Nd 同位素证据
影响因子：
3.4
作者：
S. Bowtell;R. Cliff;A. Barnicoat
通讯作者：
A. Barnicoat
瑞士-意大利阿尔卑斯山西部的地质格架和结构演化
DOI：
10.1007/978-3-0348-9098-4_16
发表时间：
1995
期刊：
Eclogae Geologicae Helvetiae
影响因子：
--
作者：
A. Escher;J. Hunziker;M. Marthaler;H. Masson;M. Sartori;A. Steck
通讯作者：
A. Steck
影响因子：
2.8
作者：
L. Husson;J. Brun;P. Yamato;C. Faccenna
通讯作者：
L. Husson;J. Brun;P. Yamato;C. Faccenna
俯冲系统中的海沟运动、板片几何形状和粘性应力
影响因子：
2.8
作者：
L. Royden;L. Husson
通讯作者：
L. Husson