The present study of field, petrological, exploration well, and seismic data describes backward-dipping duplexes comprised of phyllitic coal and bedding-parallel décollements and thrusts localized along lithological transitions in tectonically thickened Lower Devonian to lowermost Upper Devonian; uppermost Devonian–Mississippian; and uppermost Pennsylvanian–lowermost Permian sedimentary strata of the Wood Bay and/or Wijde Bay and/or Grey Hoek formations; of the Billefjorden Group; and of the Wordiekammen Formation, respectively. The study shows that these structures partially decoupled uppermost Devonian–Permian sedimentary rocks of the Billefjorden and Gipsdalen groups from Lower Devonian to lowermost Upper Devonian rocks of the Andrée Land Group and Mimerdalen Subgroup during early Cenozoic Eurekan deformation in central Spitsbergen. Eurekan strain decoupling along these structures explains differential deformation between Lower Devonian to lowermost Upper Devonian rocks of the Andrée Land Group and/or Mimerdalen Subgroup and overlying uppermost Devonian–Permian sedimentary strata of the Billefjorden and Gipsdalen groups in central–northern Spitsbergen without requiring an episode of (Ellesmerian) contraction in the Late Devonian. Potential formation mechanisms for bedding-parallel décollements and thrusts include shortcut faulting and/or formation as a roof décollement in a fault-bend hanging wall (or ramp) anticline, as an imbricate fan, as an antiformal thrust stack, and/or as fault-propagation folds over reactivated or overprinted basement-seated faults. The interpretation of seismic data in Reindalspasset indicates that Devonian sedimentary rocks of the Andrée Land Group and Mimerdalen Subgroup might be preserved east of the Billefjorden Fault Zone, suggesting that the Billefjorden Fault Zone did not accommodate reverse movement in the Late Devonian. Hence, the thrusting of Proterozoic basement rocks over Lower Devonian sedimentary rocks along the Balliolbreen Fault and fold structures within strata of the Andrée Land Group and Mimerdalen Subgroup in central Spitsbergen may be explained by a combination of down-east Carboniferous normal faulting with associated footwall rotation and exhumation, and subsequent top-west early Cenozoic Eurekan thrusting along the Billefjorden Fault Zone. Finally, the study shows that major east-dipping faults, like the Billefjorden Fault Zone, may consist of several discrete, unconnected (soft-linked and/or stepping) or, most probably, offset fault segments that were reactivated or overprinted to varying degrees during Eurekan deformation due to strain partitioning and/or decoupling along sub-orthogonal NNE-dipping reverse faults.

中文翻译：

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斯瓦尔巴特群岛中部斯匹次卑尔根的早期新生代尤里坎菌株分配和分离

目前对田间，岩石学，勘探井和地震数据的研究描述了向后倾覆的双相岩，其中包括发育性煤和顺层理理的扇形构造，以及在构造上增厚的下泥盆统至最低上泥盆统中沿岩性过渡局限的逆冲。泥盆纪至密西西比最高峰；伍德湾和（或）维德湾（Wijde Bay）和/或格雷霍克（Gray Hoek）地层的宾夕法尼亚州至最低的二叠纪沉积地层；Billefjorden集团的成员；和分别为Wordiekammen组。研究表明，在斯匹次卑尔根中部新生代尤里坎早期变形期间，这些结构使下低泥盆统的Billefjorden组和Gipsdalen组的最高泥盆纪-二叠纪沉积岩部分解耦，再到Andrée土地群和Mimerdalen子群的最低上泥盆纪岩石解耦。沿这些结构的Eurekan应变解耦解释了Andrée土地群和/或Mimerdalen子群的下泥盆纪至最低的上泥盆纪岩石之间的差异，以及Spitsbergen中北部的Billefjorden和Gipsdalen组的上泥盆纪-二叠纪沉积地层之上，而无需发生任何变化。泥盆纪晚期的（Ellesmerian）收缩。平行平行地层理理和推力的潜在形成机制包括捷径断裂和/或在断层弯曲的悬挂壁（或坡道）背斜中作为屋顶错理，形成为扇形扇形，为反形式的推力叠层和/或作为断层。 -传播在重新激活或叠印的地下室带座断层上折叠。对Reindalspasset中地震数据的解释表明，Andrée土地群和Mimerdalen子群的泥盆纪沉积岩可能保存在Billefjorden断裂带以东，这表明Billefjorden断裂带在泥盆纪晚期不适应反向运动。因此，沿着下石炭纪沉积岩沿Balliolbreen断层上冲，以及斯匹次卑尔根中部Andrée土地群和Mimerdalen子群地层内的褶皱构造，可以通过下东石炭纪正断层和相关的底盘旋转来解释。掘尸，随后沿Billefjorden断层带逆时针逆冲推进。最后，研究表明，主要的东倾断层，如Billefjorden断层带，