Birth of a plate boundary at ca. 12 Ma in the Ancestral Cascades arc, Walker Lane belt of California and Nevada
Birth of a plate boundary at ca. 12 Ma in the Ancestral Cascades arc, Walker Lane belt of California and Nevada
复制标题
板块边界的诞生在大约。
作者：
C. Busby
加州东部和内华达州西部的步行者莱恩带是加州湾扭张裂谷的最北延伸，这里大陆破裂过程尚未完成，可以在陆地上研究裂谷的启动。GPS和地震震源机制研究表明，步行者车道带目前容纳西北-东南方向的运动之间的塞拉内华达州微板块和北美板块，但裂缝的启动时间和性质仍不清楚。我提出了一个模型的板块边缘规模启动的加州湾和步行者巷transstensional裂缝在约。12 Ma;在这两个裂谷的本地化是由在俯冲相关弧的轴进行扩展，由于板卷回滚的热弱化，并在弧的热弱化加强了对厚的白垩纪岩基岩石圈配置文件在其西部边缘的向沟迁移的前体弧失速。在加州湾，由于法拉隆板块的停滞，裂谷很快就成功了，但步行者巷张性裂谷一直在沿着喀斯喀特弧的轴线，沿着门多西诺三联点向北伸展。我推断，板块边缘规模的步行者巷转换是由一个异常大，体积庞大的转换拉张弧火山中心的发展，约。11.5-9 Ma Sierra Crest-Little步行者弧火山中心。我发现，在这个大中新世弧火山中心的断层的风格密切匹配的第四纪扭张结构的中央步行者巷，它所在的地方，它不同于南部和北方的步行者巷结构。这表明，从东西向盆地和山脉伸展到西北向东南向步行者巷转换的时间转变比大多数工作者推断的要早。我还总结了新的数据，这些数据表明，中部的内华达州山脉前缘（从长谷到太浩盆地）正好位于步行者巷带内，而不是像以前的工作者推断的那样位于它的西边。步行者巷张扭作用的前端以位于张扭作用阶跃处的大型弧形火山中心为标志，这些火山中心包括约1000米的火山岩。11.5-9 Ma Sierra Crest-Little步行者火山中心;在其北部，约1000年。6.3- 4.8Ma的Ebbetts Pass火山中心和北部的Lassen活火山中心。在它的尾流中，大型裂谷火山中心位于张扭的台阶或弯曲处，包括长谷和科索火山区。我预测，
The Walker Lane belt of eastern California and western Nevada is the northernmost extension of the Gulf of California transtensional rift, where the process of continental rupture has not yet been completed, and rift initiation can be studied on land. GPS and earthquake focal mechanism studies demonstrate that the Walker Lane belt currently accommodates NW-SE–directed movement between the Sierra Nevada microplate and the North American plate, but the timing and nature of rift initiation remains unclear. I present a model for plate-margin-scale initiation of the Gulf of California and Walker Lane transtensional rifts at ca. 12 Ma; localization of rifting in both was initiated by thermal weakening in the axis of a subduction-related arc undergoing extension due to slab rollback, and thermal weakening in the arc was enhanced by stalling of the trenchward-migrating precursor arc against a thick Cretaceous batholithic lithospheric profile on its western margin. Rifting succeeded very quickly in the Gulf of California, due to stalling of Farallon slabs, but the Walker Lane transtensional rift has been unzipping northward along the axis of the Cascades arc, following the Mendocino triple junction. I infer that plate-margin-scale Walker Lane transtension was signaled by the development of an unusually large and voluminous transtensional arc volcanic center, the ca. 11.5–9 Ma Sierra Crest–Little Walker arc volcanic center. I show that the style of faulting in this large Miocene arc volcanic center closely matches that of Quaternary transtensional structures in the central Walker Lane, where it lies, and that it differs from southern and northern Walker Lane structures. This indicates that the temporal transition from E-W Basin and Range extension to NW-SE Walker Lane transtension occurred earlier than most workers have inferred. I also summarize new data which show that the central Sierra Nevada range front (from Long Valley to the Tahoe Basin) lies squarely within the Walker Lane belt, not to the west of it as previous workers have inferred. The leading tip of Walker Lane transtension is marked by large arc volcanic centers sited in transtensional stepovers; these include the ca. 11.5–9 Ma Sierra Crest–Little Walker volcanic center; north of that, the ca. 6.3–4.8 Ma Ebbetts Pass volcanic center; and north of that, the active Lassen volcanic center. In its wake, large rift volcanic centers are sited on transtensional stepovers or bends; these include the Long Valley and Coso volcanic fields. I predict that any
影响因子：
4.2
作者：
P. Ballato;D. Stockli;Mohammad Reza Ghassemi;A. Landgraf;M. Strecker;J. Hassanzadeh;A. Friedrich;S. Tabatabaei
通讯作者：
P. Ballato;D. Stockli;Mohammad Reza Ghassemi;A. Landgraf;M. Strecker;J. Hassanzadeh;A. Friedrich;S. Tabatabaei
影响因子：
2.9
作者：
C. Plattner;R. Malservisi;K. Furlong;R. Govers
通讯作者：
C. Plattner;R. Malservisi;K. Furlong;R. Govers