Arabia-Eurasia continental collision: Insights from late Tertiary foreland-basin evolution in the Alborz Mountains, northern Iran
Arabia-Eurasia continental collision: Insights from late Tertiary foreland-basin evolution in the Alborz Mountains, northern Iran
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DOI：
10.1130/b30091.1
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发表时间：
2011-01-01
影响因子：
4.9
通讯作者：
Tabatabaei, Saeid H.
中科院分区：
文献类型：
--
作者：
Ballato, Paolo;Uba, Cornelius E.;Tabatabaei, Saeid H.
人们对 15-20 m.y 的滞后时间知之甚少。存在于始新世晚期至渐新世早期的阿拉伯-欧亚大陆初始碰撞与早中新世晚期跨越碰撞带的构造和沉积过程的加速之间。厄尔布尔士山脉（伊朗北部）的孔德盆地、埃万基盆地和塞姆南盆地的始新世晚期至中新世-上新世碎屑岩和浅海沉积岩为追踪该造山带在碰撞过程框架内的演化提供了可能性。 36Ma后不久，海底火山碎屑沉积物向浅海蒸发岩和陆地沉积物的转变发生，这与沉积物来源、地层倾斜和侵蚀剥落的逆转有关。这些事件发生在俯冲弧岩浆作用终止之后，并标志着从伸展状态向收缩状态的转变，以响应大陆碰撞与拉伸阿拉伯岩石圈俯冲的开始。碰撞的早期阶段产生了与浅前陆盆地相关的地形起伏，表明缩短和构造载荷以较低的速率发生。从早中新世（17.5 Ma）开始，由于前陆盆地的启动而发生了弯曲沉降。快速的沉积物积累速度和侵蚀性的无顶趋势表明，中新世早期缩短的速度加快。我们认为，大陆碰撞开始（36 Ma）和区域变形加速（20-17.5 Ma）之间的滞后时间反映了两阶段碰撞过程，首先是拉伸岩石圈的“软”碰撞，然后是未拉伸的阿拉伯大陆岩石圈到达俯冲带后的“硬”碰撞。
A poorly understood lag time of 15-20 m.y. exists between the initial Arabia-Eurasia continental collision in late Eocene to early Oligocene time and the acceleration of tectonic and sedimentary processes across the collision zone in the early to late Miocene. The late Eocene to Miocene-Pliocene clastic and shallow-marine sedimentary rocks of the Kond, Eyvanekey, and Semnan Basins in the Alborz Mountains (northern Iran) offer the possibility to track the evolution of this orogen in the framework of collision processes. A transition from volcaniclastic submarine deposits to shallow-marine evaporites and terrestrial sediments occurred shortly after 36 Ma in association with reversals in sediment provenance, strata tilting, and erosional unroofing. These events followed the termination of subduction arc magmatism and marked a changeover from an extensional to a contractional regime in response to initiation of continental collision with the subduction of stretched Arabian lithosphere. This early stage of collision produced topographic relief associated with shallow foreland basins, suggesting that shortening and tectonic loading occurred at low rates. Starting from the early Miocene (17.5 Ma), flexural subsidence in response to foreland basin initiation occurred. Fast sediment accumulation rates and erosional unroofing trends point to acceleration of shortening by the early Miocene. We suggest that the lag time between the initiation of continental collision (36 Ma) and the acceleration of regional deformation (20-17.5 Ma) reflects a two-stage collision process, involving the "soft" collision of stretched lithosphere at first and "hard" collision following the arrival of unstretched Arabian continental litho sphere in the subduction zone.