This work focuses on the structural setting of a small area of the Murge Plateau, southern Italy, exposing Turonian bauxites and encompassing Upper Cretaceous carbonates of the Apulian Platform. By combining field geological and structural mapping with mineralogical and petrographic investigations of representative rock samples, we document the control exerted by Late Cretaceous, syn-sedimentary, high-angle faults and dilational fissures striking ca. N105E, N135E, N170E, and N45E. Altogether, these structural elements formed a few km-long, transtensional fault system along which karst-related shafts, dissolution caves, and sinkholes developed. Karst processes first affected the topmost limestone beds of the Valanginian-Cenomanian Bari Fm. Then, during Turonian, in a continental setting, cycles of terrigenous sediment deposition and weathering localized in the karst-related cavities, dilational fissures, and at the top of down-dropped fault blocks. Weathering of the Al–Si rich sediments formed bauxites made up of kaolinite, boehmite, goethite, hematite, and anatase mineral phases. The relative enrichment in kaolinite with respect to boehmite documented for the breccia and conglomerate matrix topping the bauxites is interpreted as due to lower degrees of weathering. Differently, the individual bauxite beds do not show any internal significant variation in terms of their mineral assemblages, but form angular unconformities due to syn-sedimentary faulting. The subsequent marine transgression also occurred under the influence of active tectonics, as displayed by growth folds at the bottom of the Conacian-Early Campanian Altamura Fm. The overall results of this study are in agreement with those previously reported for nearby areas of the Murge Plateau exposing Santonian limestone rocks of the Altamura Fm. Accordingly, we infer that Late Cretaceous transtensional faulting of the Apulian Platform was due to a far field stress state, likely associated to the orogenic processes that involved the northern edge of the Adriatic micro-plate.

这项工作的重点是意大利南部Murge高原的一小部分区域的结构环境，该区域暴露了土伦的铝土矿，并涵盖了Apulian平台的上白垩统碳酸盐岩。通过结合野外地质和结构测绘与代表性岩石样品的矿物学和岩石学研究，我们记录了晚白垩世，同沉积，高角度断层和扩张裂隙引起的控制作用。N105E，N135E，N170E和N45E。这些结构要素总共形成了几公里长的张性断层系统，沿着该系统形成了与岩溶有关的竖井，溶蚀洞和塌陷。喀斯特地貌过程首先影响到了瓦朗基尼-西诺曼尼亚巴里Fm的最上层石灰岩床。然后，在土伦时期，在大陆环境中，陆源性沉积物沉积和风化的周期局限在与喀斯特有关的空洞，膨胀裂缝和下垂断块的顶部。富铝硅沉积物的风化形成了铝土矿，铝土矿由高岭石，勃姆石，针铁矿，赤铁矿和锐钛矿矿物相组成。在角砾岩和铝土矿之上的角砾岩和砾岩基质中，高岭石相对于勃姆石的相对富集被认为是由于风化程度较低。不同的是，各个铝土矿床在矿物组合方面没有表现出任何内部显着变化，而是由于同沉积的断层而形成了角不整合。随后的海侵也发生在活动构造的影响下，如科纳西－早坎帕尼亚阿尔塔穆拉火山底部的生长褶皱所显示。这项研究的总体结果与先前报道的Murge高原附近地区暴露于Altamura Fm的Santonian石灰石岩石的结果一致。因此，我们推断阿普利亚平台的晚白垩世张性断层是由于远场应力状态，可能与涉及亚得里亚海微板块北缘的造山过程有关。