Abstract The Plio-Pleistocene Calvello-Anzi Basin (CAB) represents a synorogenic shallow marine to alluvial succession deposited during the late phase of the Apennine Orogenic event. While the stratigraphy and sedimentary cycles are well known, the precise role and timing of the tectonic phases affecting this area are unclear. In this paper we report the major findings from a study aimed at unraveling the signatures of the Plio-Quaternary tectonic events affecting the CAB and this portion of the Southern Apennines by using a field integrated approach characterized by facies analysis, structural surveying, and basin architecture. The CAB is located in the axial portion of the Southern Apennine chain and has a roughly E-W orientation which is at a high angle with respect the main NW-SE striking regional tectonic structures controlling the foreland-directed migration of the compression. In the study area, an approximately 1,200-meter-thick package of Zanclean (early-middle Pliocene) to Santernian (middle Pleistocene) shelf, shallow marine, and alluvial deposits accumulated during the late stages of the Apennine orogenic evolution. Within the CAB deposits we recognize two main depositional motifs which roughly correspond to previously established regional cycles that are genetically linked to two corresponding tectonic phases of the Southern Apennine chain. Our results reveal how these two main tectonic phases played a primary role in controlling the depositional architecture, facies, depocenter distribution, and the basin shape throughout the CAB's lifespan. In the proposed model, during the first depositional stage (Zanclean), the CAB formed as a wedge-top basin, controlled by the subsurface propagation of NW-SE-trending thrusts related to the main NE-SW directed shortening of the Apennines. This stage is recorded in the basal units of the CAB infill by progressive unconformities, the development of syn-tectonic shallow marine sedimentary wedges along a high gradient tectonically controlled depositional surface, and a marked SE migration of the main depocenter. During the second depositional stage (upper Piacenzian to Santernian), the CAB was controlled by a series of roughly E-W-trending normal faults which crosscut the preexisting compressional structural fabric. Syndepositional activity along these faults played a direct role in creating an E-W oriented tectonic depression and controlling the accommodation space for the upper portion of the CAB infill. This second stage is marked by two points of evidence. The first point is revealed by a southwestward migration of the CAB depocenter driven by ~90-degree rotation from a roughly NW-SE elongated pattern to roughly elongated W-E transverse to the Pliocene regional structural fabric. This depocenter drift also coincides with an abrupt change in depositional regime from shallow marine to continental sedimentation. The second and most important point of evidence is the presence of several basin-bounding extensional fault zones which cut the lower Pliocene basin-fill units. We relate these features to the middle upper Pleistocene transition to along-strike extension, widely reported in the Southern Apennines, which is related to the overall extensional regime that is acting on the chain also at present. Data from this study provide additional insight into the evolution of the Southern Apennine chain, the formation of the Plio-Pleistocene CAB, and the debated role of Quaternary tectonics on the basin's development during the post-collision orogenic phases. Given the proximity of the study area with several oil fields and considering that hydrocarbon traps in Southern Apennines are Plio-Quaternary in age, the constraints provided on the timing and the style of the regional deformation may improve the definitions of hydrocarbon traps in the buried Apulian platform.

中文翻译：

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意大利南部亚平宁山脉上新世-更新世构造事件的沉积学和地层特征：卡尔维洛-安兹盆地案例研究

摘要 上新-更新世卡尔维洛-安兹盆地 (CAB) 代表了亚平宁造山活动晚期沉积的同生浅海到冲积层序。虽然地层和沉积旋回众所周知，但影响该地区的构造阶段的确切作用和时间尚不清楚。在本文中，我们报告了一项研究的主要发现，该研究旨在通过使用以相分析、构造测量和盆地结构为特征的现场综合方法，揭示影响 CAB 和南亚平宁山脉这一部分的上新-第四纪构造事件的特征. CAB 位于南亚平宁链的轴向部分，大致呈 EW 方向，与控制前陆方向的压缩迁移的主要 NW-SE 区域构造结构呈大角度。在研究区，在亚平宁造山带演化的晚期阶段积累了约 1,200 米厚的 Zanclean（上新世中早期）至 Santernian（中更新世）陆架、浅海和冲积沉积物。在 CAB 矿床中，我们识别出两个主要的沉积基序，它们大致对应于先前建立的区域旋回，这些旋回在遗传上与南亚平宁链的两个相应构造阶段有关。我们的研究结果揭示了这两个主要构造阶段如何在 CAB 的整个生命周期中在控制沉积结构、相、沉积中心分布和盆地形状方面发挥主要作用。在提议的模型中，在第一沉积阶段（Zanclean），CAB 形成为楔形顶部盆地，由与亚平宁山脉主要 NE-SW 定向缩短相关的 NW-SE 向逆推力的地下传播控制。这一阶段记录在 CAB 填充的基底单元中，包括渐进的不整合面、沿高梯度构造控制的沉积表面的同构造浅海沉积楔的发展以及主要沉积中心的显着 SE 迁移。在第二沉积阶段（上皮亚琴阶到桑特尔阶），CAB 由一系列大致 EW 走向的正断层控制，这些断层横切了先前存在的压缩结构结构。沿这些断层的同沉积活动在形成 EW 取向的构造凹陷和控制 CAB 填充物上部的容纳空间方面发挥了直接作用。第二阶段有两个证据点。第一点是通过大约 90 度旋转驱动的 CAB 沉积中心向西南迁移，从大致 NW-SE 细长模式到横向于上新世区域结构结构的大致细长 WE。这种沉积中心漂移也与沉积制度从浅海沉积到大陆沉积的突然变化相吻合。第二个也是最重要的证据是几个盆地边界伸展断层带的存在，这些断层带切割了下上新世盆地填充单元。我们将这些特征与中更新世向沿走向伸展的过渡联系起来，在南亚平宁山脉广泛报道，这与目前作用于链的整体伸展制度有关。这项研究的数据提供了对南亚平宁链演化、上新世 CAB 的形成以及第四纪构造在碰撞后造山阶段期间盆地发展的争论作用的更多见解。鉴于研究区靠近多个油田，并考虑到亚平宁山脉南部的油气圈闭年龄为上新-第四纪，