Unconformity development in retroarc foreland basins: implications for the geodynamics of Andean-type margins
Unconformity development in retroarc foreland basins: implications for the geodynamics of Andean-type margins
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DOI：
10.1144/jgs2020-263
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发表时间：
2021-12-01
影响因子：
2.7
通讯作者：
Horton, Brian K.
中科院分区：
文献类型：
--
作者：
Horton, Brian K.
前陆盆地的不整合面可能是由盆地、邻近的褶皱逆冲带或更广泛的汇聚边缘中的构造过程产生的。前陆盆地不整合面代表从高适应性到非沉积或侵蚀条件的转变，其中沉降的中断阻止了沉积物的净积累。本研究通过考虑南美洲西部安第斯山脉的现代和古代例子，探讨了长期不整合面（> 1-20 myr）和浓缩地层剖面的成因。这些案例研究强调了安第斯型弧后前陆环境中可容纳性减少和间断发展的潜在地球动力学机制，包括：（1）缩短引起的锋面逆冲带和近前陆抬升； (2) 宽阔、低起伏的弯曲前隆起的生长和推进； (3) 前陆基底块的隆起； (4) 构造静止，伴有区域均衡回弹； (5) 斜收敛时推力加载和弯曲沉降结束； (6) 由于海平面、气候、侵蚀或运输的变化导致住宿或沉积物供应减少； (7) 平板俯冲过程中的盆地隆升； (8) 与板片窗口形成、板片断裂、板内（面内）应力升高或相关地幔过程相关的动态隆升。这些对比机制可以根据空间分布、构造背景、地层位置、古环境条件以及不整合面和浓缩剖面的持续时间来区分。
Unconformities in foreland basins may be generated by tectonic processes that operate in the basin, the adjacent fold-thrust belt or the broader convergent margin. Foreland basin unconformities represent shifts from high accommodation to non-depositional or erosional conditions in which the interruption of subsidence precludes the net accumulation of sediment. This study explores the genesis of long-duration unconformities (> 1-20 myr) and condensed stratigraphic sections by considering modern and ancient examples from the Andes of western South America. These case studies highlight the potential geodynamic mechanisms of accommodation reduction and hiatus development in Andean-type retroarc foreland settings, including: (1) shortening-induced uplift in the frontal thrust belt and proximal foreland; (2) the growth and advance of a broad, low-relief flexural forebulge; (3) the uplift of intraforeland basement blocks; (4) tectonic quiescence with regional isostatic rebound; (5) the end of thrust loading and flexural subsidence during oblique convergence; (6) diminished accommodation or sediment supply due to changes in sea-level, climate, erosion or transport; (7) basinwide uplift during flat-slab subduction; and (8) dynamic uplift associated with slab window formation, slab break-off, elevated intraplate (in-plane) stress, or related mantle process. These contrasting mechanisms can be distinguished on the basis of the spatial distribution, structural context, stratigraphic position, palaeoenvironmental conditions, and duration of unconformities and condensed sections.