Abstract Different phases of the orogen's evolutionary history can be geometrically restored by identifying associated tectonic features in the thrust-and-fold belts in the foreland basin. The geometry and fold styles allow understanding the rate of crustal shortening of the Paraguay Belt Neoproterozoic oroclinal. We suggest that high resolution airborne geophysical data provides critical information to understand the tectonic history of Brasiliano fold belts. Geophysical studies integrated to structural analysis in field mapping may unveil the crustal architecture as well as the sequence of events of rocks exposed in two structural windows of the basement in the region of Planalto da Serra and Nova Xavantina, in the state of Mato Grosso, northern segment of the Paraguay Belt, Central Brazil. The evolutive history of rocks exposed southwards of the Amazonian craton margin represents extensional tectonics followed by the development of a passive margin. It is estimated that the original width of the depositional space was ~350 km during the formation of the hyperextended platform and, after the intense shortening during the Brasiliano orogenesis, the oroclinal was restricted to ~130 km wide, in the post-deformation phase. Planalto da Serra region is characterized by asymmetrical, harmonic folds with thickened hinge zones. They show variable styles between tight and isoclinal and form pairs of EW and NE anticlines and synclines. In Nova Xavantina structural window, the magnetic lineaments mark important lithospheric discontinuities represented by the Campinapolis (CAL) and General Carneiro (GCL) lineaments, which seem to be the deep basement faults that controlled the extension and where the rift axial zone developed. The Transbrasiliano Lineament (TBL) is a major shear zone that controls the secondary lineaments propagation, forming a network of folds and drag faults, with lateral escapes and vertical movement. Between the two main lineaments occurred the deposition of sediments and volcanic successions related to Nova Xavantina Metavolcanosedimentary Sequence representing a marginal ocean basin. The transition from EW trending features of the Paraguay Belt to NE trend Araguaia Belt lies within Nova Xavantina region and is marked by the direct influence of TBL. TBL is evident in the magnetic images, forming a mosaic of different crustal blocks and corresponding to various curvilinear shear zones with unidirectional trend N30-45E. It is composed of mega-sigmoids interlaced with mainly dextral kinematics, within shallow and deep levels. During the Neoproterozoic orogeny, a foreland basin system was formed in response to the flexural subsidence due to the tectonic inversion of the basin. Several depocenters were formed and served as accumulation sites for the deposition of sediments of the Alto Paraguay Group (Raizama, Sepotuba and Diamantino formations). Gravimetric data allowed individualization of the foreland basin system, which is characterized by four discrete depozones (back-bulge, forebulge, foredeep and wedge-top), between the Amazonian Craton and the inner structural zone.

中文翻译：

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基于野外工作和高分辨率航空地球物理数据的结构解释，缩短巴西中部巴拉圭带新元古代口斜弯曲的历史

摘要 通过识别前陆盆地逆冲褶皱带的相关构造特征，可以几何还原造山带演化历史的不同阶段。几何形状和褶皱样式有助于了解巴拉圭带新元古代口斜的地壳缩短率。我们建议高分辨率机载地球物理数据为了解巴西利亚诺褶皱带的构造历史提供关键信息。在野外绘图中与结构分析相结合的地球物理研究可能会揭示地壳结构以及在北部马托格罗索州的 Planalto da Serra 和 Nova Xavantina 地区地下室的两个结构窗口中暴露的岩石的事件序列巴西中部巴拉圭带的一部分。亚马逊克拉通边缘向南出露的岩石的演化历史代表了伸展构造，随后是被动边缘的发展。据估计，在超伸展台地形成期间，沉积空间的原始宽度为~350 km，在巴西造山作用期间强烈缩短后，在变形后阶段，口斜被限制在~130 km宽。Planalto da Serra 地区的特点是不对称、和谐的褶皱和加厚的铰链区。它们在紧斜和等斜之间显示出不同的样式，并形成成对的 EW 和 NE 背斜和向斜。在 Nova Xavantina 构造窗口中，磁线标记了以 Campinapolis (CAL) 和 General Carneiro (GCL) 线为代表的重要岩石圈不连续性，这似乎是控制伸展和裂谷轴带发育的深层基底断层。Transbrasiliano Lineament (TBL) 是一个主要的剪切带，它控制着次生线的传播，形成一个褶皱和拖曳断层网络，具有横向逃逸和垂直运动。在两条主线之间发生了与代表边缘海洋盆地的 Nova Xavantina Metavolcanosedimentary 序列相关的沉积物和火山序列的沉积。巴拉圭带的 EW 向特征向东北向 Araguaia 带的过渡位于 Nova Xavantina 地区，以 TBL 的直接影响为标志。TBL在磁像中很明显，形成了不同地壳块体的镶嵌，对应于具有单向趋势N30-45E的各种曲线剪切带。它由与主要右旋运动学交错的巨型 sigmoids 组成，位于浅层和深层。新元古代造山运动期间，盆地构造反转导致弯曲沉降，形成前陆盆地系统。形成了几个沉积中心，并作为上巴拉圭组（Raizama、Sepotuba 和 Diamantino 地层）沉积物沉积的聚集地。重力数据允许前陆盆地系统的个性化，其特征是亚马逊克拉通和内部构造带之间有四个离散的沉积带（后隆起、前隆起、前深和楔顶）。前陆盆地系统因盆地构造反转导致的弯曲沉降而形成。形成了几个沉积中心，并作为上巴拉圭组（Raizama、Sepotuba 和 Diamantino 地层）沉积物沉积的聚集地。重力数据允许前陆盆地系统的个性化，其特征是亚马逊克拉通和内部构造带之间有四个离散的沉积带（后隆起、前隆起、前深和楔顶）。前陆盆地系统因盆地构造反转导致的弯曲沉降而形成。形成了几个沉积中心，并作为上巴拉圭组（Raizama、Sepotuba 和 Diamantino 地层）沉积物沉积的聚集地。重力数据允许前陆盆地系统的个性化，其特征是亚马逊克拉通和内部构造带之间有四个离散的沉积带（后隆起、前隆起、前深和楔顶）。