What feeds shelf‐edge clinoforms over margins deprived of adjacent land sources? An example from southeastern Brazil,Basin Research

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What feeds shelf‐edge clinoforms over margins deprived of adjacent land sources? An example from southeastern Brazil
Basin Research ( IF 2.8 ) Pub Date : 2020-04-01 , DOI: 10.1111/bre.12397
Uri Schattner ₁ , Francisco José Lobo ₂ , Adrián López‐Quirós ₂ , Jorge Luiz Passos Nascimento ₃ , Michel Michaelovitch Mahiques _{3,

4}

Affiliation

[Ocean bottom currents shape shelf‐edge clinoforms offshore Brazil. , Abstract In southeastern Brazil, the Serra do Mar coastal mountain range blocks the sediment influx from arriving at a ca. 1,500 km long continental margin comprising Santos and Pelotas basins. Despite this deprivation, the margin accumulated a ca. 1 km thick sedimentary succession since the Mid‐Miocene. Examination of seismic reflection and oceanographic data indicates that shelf‐margin clinoform formation exhibits a regional variability, with major sigmoidal clinoforms developed in the transitional area between both basins. Laterally, poorly developed oblique clinoforms constitute isolated depocenters along the shelf margin. The continuous clinoform development in the transitional area is attributed to the major influence on sediment transport patterns of several ocean bottom currents flowing along the margin, such as the Brazil Coastal Current, the Brazil Current and the Intermediate Water Brazil Current. These currents erode, transport and distribute sediments across the shelf break and upper slope from distant sediment sources located either north or south of the study area. The progressive southward strengthening of the Brazil Current could be responsible for a major southward sediment redistribution from the northern Campos Basin, and/or for sediment entrainment from northward‐induced transport by the Brazil Coastal Current, originally derived from the De la Plata Estuary. In the transition between Santos and Pelotas basins, the Intermediate Water Brazil Current splits forming the Santos Bifurcation, allowing for a continuous depositional process and clinoform generation. We suggest that ocean bottom currents may shape other shelf‐edge ‘contouritic clinoforms’ in continental margins mainly constructed by along‐strike sediment transport largely driven by long‐term geostrophic currents.]

中文翻译：

是什么滋养了被剥夺了相邻陆地资源的边缘大陆架边缘的斜面形态？巴西东南部的一个例子

[海底洋流塑造了巴西近海的陆架边缘斜坡。, 摘要在巴西东南部，Serra do Mar 沿海山脉阻止了沉积物流入到达约。1,500 公里长的大陆边缘，包括桑托斯和佩洛塔斯盆地。尽管有这种剥夺，保证金积累了大约。中中新世以来 1 公里厚的沉积层序。地震反射和海洋学数据表明，陆架边缘斜坡地层具有区域变异性，在两个盆地之间的过渡区发育主要的 S 形斜坡。横向上，发育不良的斜斜坡构成了沿陆架边缘的孤立沉积中心。过渡区的连续斜坡发育主要是由于巴西沿岸流、巴西海流和中水巴西海流等沿边缘流动的几种海底海流对沉积物输移模式的主要影响。这些洋流侵蚀、运输和分布来自研究区北部或南部的遥远沉积物源的沉积物穿过陆架断裂和上坡。巴西洋流的逐步向南加强可能是坎波斯盆地北部主要向南沉积物重新分布的原因，和/或由最初源自德拉普拉塔河口的巴西沿海洋流向北诱导输送的沉积物夹带。在桑托斯盆地和佩洛塔斯盆地之间的过渡中，中间水巴西洋流分裂形成桑托斯分岔，允许连续沉积过程和斜面生成。我们认为，海底洋流可能会在大陆边缘形成其他大陆架边缘的“轮廓倾斜的斜岩体”，主要由长期地转洋流驱动的沿走向沉积物迁移构成。]

更新日期：2020-04-01

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