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Reconciling along-strike disparity in slip displacement of the San Andreas fault, central California, USA
GSA Bulletin ( IF 4.9 ) Pub Date : 2021-07-01 , DOI: 10.1130/b35681.1
Jared T. Gooley 1 , Glenn R. Sharman 2 , Stephan A. Graham 1
Affiliation  

The correlation of the ca. 23 Ma Pinnacles and Neenach volcanic complexes provides the most robust estimate on the timing and magnitude of Neogene right-lateral displacement on the San Andreas strike-slip fault system (California, United States). Displacement of ∼315 km has been applied rigorously along the plate margin to guide reconstruction of offset paleogeographic features. We present new detrital zircon U-Pb geochronology from the La Honda and western San Joaquin basins to document sediment provenance and reevaluate compositional constraints on a hypothesized key cross-fault tie (i.e., Castle Rock–Recruit Pass submarine fan system). Whereas the Upper Oligocene–Lower Miocene Vaqueros Formation of the La Honda basin was likely recycled from or shared a similar southern Sierra Nevada–western Mojave source with the underlying Eocene stratigraphy, we found that the Temblor Formation of the central Temblor Range (e.g., Recruit Pass submarine fan) was derived directly from Late Cretaceous northern Salinian basement. Furthermore, the Carneros Sandstone of the northern Temblor Range had a central Sierra Nevada batholith source that was likely recycled during early Miocene unroofing of the underlying stratigraphy. Conversely, strata of the southwest San Joaquin basin have provenance characteristics that match more closely with those of the La Honda basin.Our data preclude a contiguous Castle Rock–Recruit Pass submarine fan system across the San Andreas fault. These relationships are resolved by restoring the ca. 105–100 Ma basement of the northernmost Salinian block an additional ∼45 km or greater farther south relative to the Sierra Nevada batholith during late Oligocene–early Miocene time. Inconsistency in displacement along the San Andreas fault with the coeval correlation of the Pinnacles–Neenach volcanic complex is reconciled by postdepositional Miocene–Quaternary off-fault NW-SE structural shortening via major thrusts and/or transrotation of the Tehachapi block, in combination with extension of the northern Salinian block. This additional displacement reduces the need for pre–28 Ma slip on the San Andreas or predecessor faults to resolve Cretaceous through Eocene cross-fault relationships and reconciles an early Miocene discrepancy with Pacific–North America relative plate motion. This study highlights the fact that displacement histories of major strike-slip faults are divergent across changing structural domains, and recognition of slip disparities can constrain the magnitude of deformation.

中文翻译:

调和美国加利福尼亚州中部圣安德烈亚斯断层滑动位移的沿走向差异

的相关性。23 Ma Pinnacles 和 Neenach 火山复合体对圣安德烈亚斯走滑断层系统(美国加利福尼亚州)上新近纪右侧位移的时间和幅度提供了最可靠的估计。约 315 公里的位移已沿板块边缘严格应用,以指导偏移古地理特征的重建。我们提出了来自 La Honda 和西部 San Joaquin 盆地的新碎屑锆石 U-Pb 年代学,以记录沉积物来源并重新评估假设的关键交叉断层连接(即 Castle Rock-Recruit Pass 海底扇系统)的成分限制。而 La Honda 盆地的上渐新世 – 下中新世 Vaqueros 组可能是从类似的内华达山脉南部 – 莫哈韦西部的源头回收或共享的,其下伏始新世地层,我们发现中央 Temblor 山脉(例如 Recruit Pass 海底扇)的 Temblor 组直接来自晚白垩世北部萨利尼亚基底。此外,Temblor 山脉北部的 Carneros 砂岩有一个中央内华达山脉的基岩源,它可能在下伏地层早期中新世揭顶过程中被回收利用。相反,圣华金盆地西南部的地层具有与拉本田盆地更接近的物源特征。我们的数据排除了跨越圣安德烈亚斯断层的连续 Castle Rock-Recruit Pass 海底扇系统。这些关系通过恢复 ca 来解决。在渐新世晚期 - 中新世早期,最北端的萨利尼亚地块的 105-100 Ma 基底相对于内华达山脉岩基向南额外约 45 公里或更远。沿着圣安德烈亚斯断层的位移与尖峰石阵-尼纳赫火山复合体的同时期相关性的不一致通过沉积后中新世-第四纪断层 NW-SE 构造缩短通过特哈查比块的主要逆冲断层和/或转转结合伸展来协调北萨利尼亚地块。这种额外的位移减少了圣安德烈亚斯或前身断层上 28 Ma 之前的滑移的需要,以通过始新世交叉断层关系解决白垩纪,并调和中新世早期差异与太平洋-北美相对板块运动。这项研究强调了一个事实,即主要走滑断层的位移历史在不断变化的构造域中是不同的,并且对滑动差异的识别可以限制变形的幅度。
更新日期:2021-06-30
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