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Upper oligocene-miocene deposits of Eastern Amazonia: Implications for the collapse of Neogene carbonate platforms along the coast of northern Brazil
Palaeogeography, Palaeoclimatology, Palaeoecology ( IF 2.6 ) Pub Date : 2021-02-01 , DOI: 10.1016/j.palaeo.2020.110178
Afonso César Rodrigues Nogueira , Kamilla Borges Amorim , Ana Maria Góes , Werner Truckenbrodt , Setembrino Petri , Anna Andressa Evangelista Nogueira , José Bandeira , Joelson Lima Soares , Lohan Barbosa Baía , Manoel Imbiriba Júnior , Isaac Salém Bezerra , Camila C. Ribas , Joel Cracraft

Abstract Mixed carbonate-siliciclastic platforms developed in the onshore and offshore zones of several basins along the Amazonian coast starting in the Palaeocene. The shutdown of Miocene carbonate accumulation in distinct tectonic settings shows different evolutionary histories along the Eastern Amazonian coast. The shutdown has been attributed to the abundant siliciclastic fluvial inflow from the Andean Amazon River during the late Miocene. The combination of previously collected geological information and new stratigraphic data from the Oligocene-Miocene transgressive-regressive Pirabas-Barreiras sequence exposed on the Bragantina Platform of the Eastern Amazonian coast reveals the collapse of the carbonate platform by the Barreiras fan delta deposits during the middle Miocene. The development of the Barreiras fan delta, fed by a cratonic source exposed during the Langhian (15–10 Ma) sea-level fall, was concomitant with the so-called Cratonic Amazon River that preceded the transcontinental Andean Amazon River. The climax of sea-level fall caused the maximum expansion of the Barreiras fan delta, which reached the Marajo and Para-Maranhao basins. The progressive denudation of the region, low fluvial inflow, and extensive Tortonian sea-level fall (11–8 Ma) resulted in the inactivity of the Barreiras Delta. Consequently, the exposure and subsequent intense lateritization of these degraded deposits generated an extensive unconformity that lasted until the deposition of Pleistocene Post-Barreiras sediments.

中文翻译:

亚马逊东部上渐新世-中新世沉积物:对巴西北部海岸新近系碳酸盐岩台地坍塌的影响

摘要 从古新世开始,在亚马逊沿岸几个盆地的陆上和海上区域发育碳酸盐-硅质碎屑混合平台。不同构造环境中中新世碳酸盐沉积的关闭显示了亚马逊东部沿岸不同的进化历史。关闭归因于晚中新世期间来自安第斯亚马逊河的大量硅质碎屑河流流入。之前收集的地质信息和新世-中新世海进-海退 Pirabas-Barreiras 序列的新地层数据相结合,该层序暴露在亚马逊东部海岸 Bragantina 平台上,揭示了中中新世 Barreiras 扇三角洲沉积物对碳酸盐岩台地的坍塌. 巴雷拉斯扇三角洲的发展,由朗格 (Langhian) (15-10 Ma) 海平面下降期间暴露的克拉通源供给,伴随着横贯大陆的安第斯亚马逊河之前的所谓克拉通亚马逊河。海平面下降的高潮导致 Barreiras 扇三角洲的最大扩张,到达 Marajo 和 Para-Maranhao 盆地。该地区的逐渐剥蚀、河流入流量低和托托尼亚海平面大范围下降(11-8 Ma)导致巴雷拉斯三角洲的不活动。因此,这些退化沉积物的暴露和随后的强烈红土化产生了广泛的不整合,一直持续到更新世后巴雷拉斯沉积物的沉积。伴随着横贯大陆的安第斯亚马逊河之前的所谓克拉通亚马逊河。海平面下降的高潮导致 Barreiras 扇三角洲的最大扩张,到达 Marajo 和 Para-Maranhao 盆地。该地区的逐渐剥蚀、河流入流量低和托托尼亚海平面大范围下降(11-8 Ma)导致巴雷拉斯三角洲的不活动。因此,这些退化沉积物的暴露和随后的强烈红土化产生了广泛的不整合,一直持续到更新世后巴雷拉斯沉积物的沉积。伴随着横贯大陆的安第斯亚马逊河之前的所谓克拉通亚马逊河。海平面下降的高潮导致 Barreiras 扇三角洲的最大扩张,到达 Marajo 和 Para-Maranhao 盆地。该地区的逐渐剥蚀、河流入流量低和托托尼亚海平面大范围下降(11-8 Ma)导致巴雷拉斯三角洲的不活动。因此,这些退化沉积物的暴露和随后的强烈红土化产生了广泛的不整合,一直持续到更新世后巴雷拉斯沉积物的沉积。Tortonian 海平面大范围下降(11-8 Ma)导致 Barreiras 三角洲不活动。因此,这些退化沉积物的暴露和随后的强烈红土化产生了广泛的不整合,一直持续到更新世后巴雷拉斯沉积物的沉积。Tortonian 海平面大范围下降(11-8 Ma)导致 Barreiras 三角洲不活动。因此,这些退化沉积物的暴露和随后的强烈红土化产生了广泛的不整合,一直持续到更新世后巴雷拉斯沉积物的沉积。
更新日期:2021-02-01
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