Alluvial sedimentation and tectonostratigraphic evolution in a narrow extensional zigzag basin margin (northern Teruel Basin, Spain)

作者：Lope Ezquerro,Aránzazu Luzón,Jose L.Simón,Carlos L.Liesa

摘要：The northern part of the eastern margin of the extensional Neogene Teruel Basin(central-eastern Spain)consists of a non-linear,zigzag fault zone made of alternating ca.2 km long,NNW-SSE trending segments and shorter NNESSW ones.Good outcrop conditions made possible a comprehensive integrated stratigraphic and structural study,especially focused on coarse clastic sediments deposited along the basin margin.Well-exposed stratal relationships with boundary faults,allowed the analysis of tectonic influence on sedimentation.Synsedimentary deformation includes growth faulting,rollover anticlines,and monoclines and associated onlap stratal terminations,angular unconformities,and other complex growth strata geometries.One of them is the onlap-over-rollover bed arrangement described here for the first time,which reveals the competition between tectonic subsidence and sedimentary supply.Both,the structural inheritance(dense Mesozoic fracture grid)and the dominant,nearly‘multidirectional’(σ1 vertical,σ2≈σ3),Pliocene extensional regime withσ3 close to E-W,are considered to have controlled the margin structure and evolution.Tectono-stratigraphic evolution includes:(i)reactivation of inherited NNW-SSE faults and development of W-SW-directed small alluvial fans(SAF)while NNE-SSW segments acted as gentle relay ramp zones;(ii)progressive activation of NNE-SSW faults and development of NW-directed very small alluvial fans(VSAF);during stages i and ii sediments were trapped close to the margin,avoiding widespread progradation;(iii)linking of NNW-SSE and NNE-SSW structural segments,overall basin sinking and widespread alluvial progradation;(iv)fault activity attenuation and alluvial retrogradation.The particular structure and kinematic evolution of this margin controlled alluvial system patterns.Size of alluvial fans,directly set up at the border faults,was conditioned by the narrowness of the margin,small catchment areas,and proximity between faults,which prevented the development of large alluvial fans.The size of the rel

發文機構：Departamento de Ciencias de la Tierra

關鍵詞：EXTENSIONALBASINALLUVIALfanStratalSTACKINGpatternStructuralinheritanceFaultlinkage

分類號： TV1[水利工程]