Abstract We present a multidisciplinary study to decipher the controls of deformation on fluid flow regime in fold and thrust belts using the Lower Pedraforca thrust sheet in the SE Pyrenees as an example. We integrate field-based and petrographic observations and geochemical and geochronological data to differentiate seven types of fractures, eight types of calcite cement (Cc1 to Cc8) and two sets of stylolites during the deformation stretching the studied thrust sheet. During syn-sedimentary hydroplastic normal faulting affecting poorly consolidated Upper Cretaceous and Eocene syn-orogenic sediments, calcite cement did not precipitate. During burial, bed-parallel stylolites formed and Cc1 and Cc2 precipitated from formation waters in a closed palaeohydrological system. During the layer-parallel shortening, Cc3 precipitated from formation waters (~+5.4‰ VSMOW) with 87Sr/86Sr ratios of 0.707922 and at ~70 °C. Cc4 precipitated from formation waters recording different burial conditions, as the up to 4‰ dispersion in δ18O of this cement suggests. Contrarily, during folding and thrusting, Cc5 to Cc7 precipitated in an open palaeohydrological system. Cc6 precipitated from formation waters (~+5‰ VSMOW), with 87Sr/86Sr ratios of 0.707817 and at ~75 °C. These fluids carried hydrocarbons and probably interacted with Upper Triassic evaporites. An 87Sr/86Sr ratio of 0.708230 for Cc5 indicates that formation waters also interacted with clays within continental deposits. During this period, stylolites formed in relation to faulting, and previous hydroplastic normal faults reactivated as reverse and strike-slip faults allowing fluid flow. Cc7 precipitated after Cc6, also from fluids in isotopic disequilibrium with their adjacent host rock. The fluid system continued open during the Oligocene, when Cc8 precipitated in normal faults affecting syn-orogenic conglomerates deposited during the reactivation of the Lower Pedraforca thrust sheet. The influence of deformation on fluid flow observed in the Lower Pedraforca thrust sheet is similar to that observed in other fractured areas worldwide.

中文翻译：

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从水塑性到脆性变形：控制褶皱和推力带中的流体流动。从下 Pedraforca 推力片（SE Pyrenees）获得的见解

摘要 我们提出了一项多学科研究，以东南比利牛斯山脉的下 Pedraforca 逆冲片为例，解读褶皱和逆冲带中流体流动状态的变形控制。我们整合了基于实地和岩相学的观察以及地球化学和地质年代学数据，以在拉伸研究的推力片的变形过程中区分七种类型的裂缝、八种方解石胶结物（Cc1 到 Cc8）和两组缝合线。在影响不牢固的上白垩统和始新世同造山沉积物的同沉积水塑性正断层作用期间，方解石胶结物没有沉淀。在埋藏过程中，在封闭的古水文系统中，形成了平行床层的缝合线，Cc1 和 Cc2 从地层水中沉淀出来。在平行层缩短过程中，Cc3 从地层水中沉淀 (~+5.4‰ VSMOW)，87Sr/86Sr 比率为 0.707922，在~70 °C 下。从记录不同埋藏条件的地层水中沉淀的 Cc4，正如该胶结物在 δ18O 中高达 4‰ 的分散所表明的那样。相反，在折叠和逆冲过程中，Cc5 到 Cc7 在开放的古水文系统中沉淀。Cc6 从地层水中沉淀 (~+5‰ VSMOW)，87Sr/86Sr 比率为 0.707817，温度约为 75 °C。这些流体携带碳氢化合物并可能与上三叠统蒸发岩相互作用。Cc5 的 87Sr/86Sr 比率为 0.708230，表明地层水也与大陆沉积物中的粘土相互作用。在此期间，与断层相关的缝合线形成，先前的水塑性正断层重新激活为反向和走滑断层，允许流体流动。Cc7 在 Cc6 之后沉淀，同样来自与其相邻主岩同位素不平衡的流体。流体系统在渐新世期间继续开放，当时 Cc8 在正断层中沉淀，影响了在下佩德拉福卡逆冲断层重新活动期间沉积的同造砾岩。在下佩德拉福卡冲断层观察到的变形对流体流动的影响与在全球其他裂缝区观察到的相似。