Large sediment masses are transferred over many hundreds of kilometres along the coast of passive continental margins worldwide. The relevance of such a phenomenon for source-to-sink studies, environmental issues, and coastal management remains largely unperceived. This study traces the paths of volcaniclastic sand along ca 2170 km of the Argentine coast and documents a 760 km long cell of littoral transport extending from the formerly larger Río Colorado delta to the edge of the Río de la Plata mouth. During deglaciation stages and humid periods of the Pleistocene, a much greater sediment volume than today was transferred by the Desaguadero and Colorado rivers from the highest-relief tract of the Andean Cordillera to the Atlantic Ocean. Amphibole-rich sand originally supplied by the Río Desaguadero is being recycled today from Pampean lowlands to feed the beaches along Río de la Plata southern shores, whereas pure quartzose sand of Río Paraná is found only adjacent to its prograding delta. Augite-rich sand supplied by the Río Colorado is dominant along the coast of the Buenos Aires Province, where it mixes locally with coarser-grained quartz-rich detritus recycled in the urbanized Mar del Plata area. Hypersthene-rich sand of the Río Negro is dispersed both north and south of the mouth, where heavy-mineral-rich lag deposits are formed in areas of accelerated erosion and retreating sea cliffs. Changes of mineralogical signatures during long-distance littoral transport are largely ascribed to local supply from coastal erosion or hydrodynamic effects rather than to selective breakdown of labile grains. Whereas the relative abundance of amphibole and pyroxene is largely independent of transport distance, olivine is depleted both in the northern part of the Colorado littoral cell and south of the Río Negro mouth, which is chiefly ascribed to dilution by recycling of Neogene sediments that have undergone early intrastratal dissolution rather than to mechanical loss.

中文翻译：

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从巴塔哥尼亚到拉普拉塔河：安第斯火山碎屑砂沿阿根廷被动边缘的多步长距离沿海输送

大量沉积物沿全球被动大陆边缘海岸转移数百公里。这种现象与源汇研究、环境问题和沿海管理的相关性在很大程度上仍未被意识到。这项研究追踪了火山碎屑砂沿加州的路径阿根廷海岸 2170 公里，记录了 760 公里长的沿海运输单元，从以前较大的科罗拉多河三角洲一直延伸到拉普拉塔河口的边缘。在更新世的冰川消融阶段和潮湿时期，德萨瓜德罗河和科罗拉多河从安第斯山脉的最高地势带转移到大西洋的沉积物量比今天大得多。最初由 Río Desaguadero 提供的富含角闪石的沙子今天从 Pampean 低地被回收，以供给拉普拉塔河 (Río de la Plata) 南岸沿岸的海滩，而巴拉那河 (Río Paraná) 的纯石英沙仅在其进积三角洲附近发现。Río Colorado 提供的富含 Augite 的沙子在布宜诺斯艾利斯省沿岸占主导地位，在那里，它与在城市化的马德普拉塔地区回收的粗粒富含石英的碎屑在当地混合。Río Negro 富含 Hypersthene 的沙子分散在河口的北部和南部，在加速侵蚀和后退的海崖区域形成了富含矿物质的沉积物。长距离沿海运输过程中矿物学特征的变化主要归因于海岸侵蚀或水动力效应的当地供应，而不是不稳定谷物的选择性分解。而角闪石和辉石的相对丰度在很大程度上与运输距离无关，而橄榄石在科罗拉多沿岸细胞的北部和里奥内格罗河口的南部都已枯竭，