The Piedra Buena Terrace (PBT), situated in the Patagonian continental slope, is swept by the vigorous flow of Antarctic-sourced bottom water masses, and intersected by a considerable submarine canyon system. It thus represents a world-class natural laboratory to investigate the sedimentary dynamics of deep-ocean settings influenced by both, along-slope, and down-slope sedimentary processes. In the framework of the Pampa Azul project, the PBT was surveyed with swath bathymetry and a high-resolution parametric sub-bottom seismic profiler and sampled at several locations with a 7 m long gravity corer. Through the integration of the acoustic data, grain size results from a sediment core and two AMS ¹⁴C ages this work attempts to: (1) describe for the first time the detailed geomorphology of a poorly known region of the Patagonian continental slope; (2) depict the principal sub-surface seismic units, illustrating their internal structure, geometry, and distribution; (3) establish a correlation between sub-surface seismic facies and sediment deposits using the first age constraints for this region; (4) propose a model with the depositional history of the PBT, focusing on the interaction between along-slope and down-slope processes and seafloor morphology. The acquired bathymetric data imaged with unprecedent detail the geomorphology of the southern part of the PBT revealing the presence of a field of kilometric-sized, sub-circular, crater-like depressions, and a submarine canyon. The analyzed seismic sub-bottom profiles showed that the shallow sedimentary structure of the study area is represented by patchy-mounded deposits characterized by three distinctive features: cyclic stacks of two seismic facies (FA and FB), mounded shape, and preferential location northwards the morphological depressions and the submarine canyon. Integration of a seismic sub-bottom profile with one sediment core indicates that the alternation of seismic facies reflects variations in the hydrodynamic conditions. FA is related to a high to moderate energy medium with input of terrigenous material and FB is related to a low energy environment with a limited contribution of sediments from the continent. The patchy distribution, mounded shape and preferential location are associated with hydrodynamic processes occurring between the geomorphological features and the north-flowing Antarctic bottom currents, which result in the deposition of mounded contourites in the northern flank of depressions and hybrid along-slope down-slope deposits northwards a submarine canyon. The ¹⁴C ages constrain the chronological framework of these sediments to the Late-Pleistocene. This is in contrast with previous investigations that have suggested much older ages (Late Miocene) for the sub-surface sediments of PBT. Finally, a conceptual model is here proposed to illustrate the Late Quaternary sediment depositional history of the PBT where the interaction between north-flowing bottom contouritic currents and seafloor relief played an important role in the deposition and preservation of sediments in this area.

位于巴塔哥尼亚大陆坡的Piedra Buena阶地（PBT）被南极来源的底部水团的猛烈吹扫所扫除，并与相当大的海底峡谷系统相交。因此，它代表了世界一流的自然实验室，致力于研究受沿坡和下坡沉积过程影响的深海环境的沉积动力学。在潘帕阿祖尔（Pampa Azul）项目的框架中，对PBT进行了条带测深和高分辨率参数化亚底部地震剖面仪的调查，并在多个位置使用7 m长的重力岩心取样器进行了采样。通过声数据的整合，沉积物芯和两个AMS ¹⁴产生了晶粒尺寸这项工作试图通过C时代：（1）首次描述巴塔哥尼亚大陆斜坡一个鲜为人知的地区的详细地貌；（2）描述主要的地下地震单元，并说明其内部结构，几何形状和分布；（3）利用该地区的第一年龄约束，建立地下地震相与沉积物沉积之间的相关性；（4）提出了一个具有PBT沉积历史的模型，重点是沿斜坡和下坡过程与海床形态之间的相互作用。用前所未有的细节成像的获取的测深数据，详细揭示了PBT南部的地貌，揭示出存在一个千米大小，亚圆形，火山口状凹陷和海底峡谷的区域。分析后的地震亚底剖面表明，研究区的浅层沉积结构以斑块状沉积物为代表，这些沉积物具有三个鲜明的特征：两个地震相（FA和FB）的循环叠层，丘形形状以及北偏北的优先位置。形态上的凹陷和海底峡谷。地震子底部剖面与一个沉积岩心的整合表明，地震相的交替反映了流体动力条件的变化。FA与输入陆源物质的高至中等能量介质有关，而FB与低能环境有关，该大陆的沉积物贡献有限。零散的分布，丘形和优先位置与地貌特征和北向南极洋流之间发生的水动力过程有关，这导致丘陵凹陷侧面北部堆积了丘状轮廓岩，并向海底北面形成了混合的沿斜坡向下坡的沉积物。峡谷。这¹⁴ C年龄将这些沉积物的时间框架限制为晚更新世。这与先前的研究相反，先前的研究表明PBT的地下沉积物年龄要晚得多（中新世晚期）。最后，这里提出了一个概念模型来说明PBT的第四纪晚期沉积沉积历史，其中北流底部轮廓流与海底起伏之间的相互作用在该区域的沉积和沉积中起着重要作用。