Quantification of three‐dimensional folding using fluvial terraces: A case study from the Mushi anticline, northern margin of the Chinese Pamir

Fold deformation in three dimensions involves shortening, uplift, and lateral growth. Fluvial terraces represent strain markers that have been widely applied to constrain a fold's shortening and uplift. For the lateral growth, however, the utility of fluvial terraces has been commonly ignored. Situated along northern margin of Chinese Pamir, the Mushi anticline preserves, along its northern flank, flights of passively deformed fluvial terraces that can be used to constrain three‐dimensional folding history, especially lateral growth. The Mushi anticline is a geometrically simple fault‐tip fold with a total shortening of 740 ± 110 m and rock uplift of ~1300 m. Geologic and geomorphic mapping and dGPS surveys reveal that terrace surfaces perpendicular to the fold's strike display increased rotation with age, implying the fold grows by progressive limb rotation. We use a pure‐shear fault‐tip fold model to estimate a uniform shortening rate of 1.5 + 1.3/−0.5 mm/a and a rock‐uplift rate of 2.3 + 2.1/−0.8 mm/a. Parallel to the fold's strike, longitudinal profiles of terrace surfaces also display age‐dependent increases in slopes. We present a new model to distinguish lateral growth mechanisms (lateral lengthening and/or rotation above a fixed tip). This model indicates that eastward lengthening of the Mushi anticline ceased by at least ~134 ka and its lateral growth has been dominated by rotation. Our study confirms that terrace deformation along a fold's strike not only can constrain the lateral lengthening rate but can serve to quantify the magnitude and rate of lateral rotation: attributes that are commonly difficult to define when relying on other geomorphic criteria.

[1]  Jie Chen,et al.  Equivalency of geologic and geodetic rates in contractional orogens: New insights from the Pamir Frontal Thrust , 2012 .

[2]  J. Malavieille,et al.  Experimental modelling of orogenic wedges: A review , 2012 .

[3]  R. Anderson,et al.  Tectonic Geomorphology: Burbank/Tectonic Geomorphology , 2011 .

[4]  Jie Chen,et al.  Late Miocene-Pliocene deceleration of dextral slip between Pamir and Tarim: Implications for Pamir orogenesis , 2011 .

[5]  D. Burbank,et al.  Kinematic implications of consequent channels on growing folds , 2011 .

[6]  Jie Li,et al.  GPS velocity field for the Tien Shan and surrounding regions , 2010 .

[7]  S. Read,et al.  Along‐strike growth of the Ostler fault, New Zealand: Consequences for drainage deflection above active thrusts , 2010 .

[8]  J. Avouac,et al.  The Neogene Xiyu Formation, a diachronous prograding gravel wedge at front of the Tianshan: Climatic and tectonic implications , 2009 .

[9]  Jie Chen,et al.  Temporal constraints and pulsed Late Cenozoic deformation during the structural disruption of the active Kashi foreland, northwest China , 2008 .

[10]  Isabelle Manighetti,et al.  Incremental growth of normal faults: Insights from a laser-equipped analog experiment , 2008 .

[11]  F. Graveleau,et al.  Analogue modelling of the interaction between tectonics, erosion and sedimentation in foreland thrust belts , 2008 .

[12]  Jie Chen,et al.  Chronology and tectonic controls of Late Tertiary deposition in the southwestern Tian Shan foreland, NW China , 2007 .

[13]  A. Replumaz,et al.  Modeling the evolution of continental subduction processes in the Pamir–Hindu Kush region , 2007 .

[14]  J. Avouac,et al.  Kinematic analysis of the Pakuashan fault tip fold, west central Taiwan: Shortening rate and age of folding inception , 2007 .

[15]  Jie Chen,et al.  Quantification of growth and lateral propagation of the Kashi anticline, southwest Chinese Tian Shan , 2007 .

[16]  J. Avouac,et al.  Kinematics of fault‐related folding derived from a sandbox experiment , 2007 .

[17]  J. Suppe,et al.  Mechanisms of active folding of the landscape (southern Tian Shan, China) , 2007 .

[18]  S. Read,et al.  Geomorphic constraints on listric thrust faulting: Implications for active deformation in the Mackenzie Basin, South Island, New Zealand , 2007 .

[19]  J. Avouac,et al.  Modeling the shortening history of a fault tip fold using structural and geomorphic records of deformation , 2007 .

[20]  A. Wintle,et al.  A new OSL chronology for dust accumulation in the last 130,000 yr for the Chinese Loess Plateau , 2007, Quaternary Research.

[21]  Jie Chen,et al.  Late Oligocene–Early Miocene initiation of shortening in the Southwestern Chinese Tian Shan: Implications for Neogene shortening rate variations , 2006 .

[22]  Jie Chen,et al.  Kinematic models of fluvial terraces over active detachment folds : Constraints on the growth mechanism of the Kashi-Atushi fold system, Chinese Tian Shan , 2006 .

[23]  J. Jackson,et al.  Combining geomorphic observations with in situ cosmogenic isotope measurements to study anticline growth and fault propagation in Central Otago, New Zealand , 2006 .

[24]  E. Fielding,et al.  Growth of South Rough Ridge, Central Otago, New Zealand: using in situ cosmogenic isotopes and geomorphology to study an active, blind reverse fault , 2005 .

[25]  Jie Chen,et al.  Detachment folding in the Southwestern Tian Shan -Tarim foreland, China: shortening estimates and rates , 2004 .

[26]  G. Simpson.  Role of river incision in enhancing deformation , 2004 .

[27]  Guangjian Wu,et al.  A 900 k.y. record of strath terrace formation during glacial-interglacial transitions in northwest China , 2003 .

[28]  P. Molnar,et al.  Late Quaternary slip rates across the central Tien Shan, Kyrgyzstan, central Asia , 2002 .

[29]  R. Anderson,et al.  Numerical modeling of fluvial strath-terrace formation in response to oscillating climate , 2002 .

[30]  Jie Chen,et al.  Magnetochronology of the Upper Cenozoic strata in the Southwestern Chinese Tian Shan: rates of Pleistocene folding and thrusting , 2002 .

[31]  C. Doubre,et al.  Slip accumulation and lateral propagation of active normal faults in Afar , 2001 .

[32]  Jérôme Lavé,et al.  Active folding of fluvial terraces across the Siwaliks Hills, Himalayas of central Nepal , 2000 .

[33]  Bertrand Meyer,et al.  Growth folding and active thrusting in the Montello region, Veneto, northern Italy , 2000 .

[34]  E. Keller,et al.  Geomorphic criteria to determine direction of lateral propagation of reverse faulting and folding , 1999 .

[35]  Douglas W. Burbank,et al.  Partitioning of intermontane basins by thrust‐related folding, Tien Shan, Kyrgyzstan , 1999 .

[36]  J. Angelier,et al.  Morphotectonic evidence from lateral propagation of an active frontal fold; Pakuashan anticline, foothills of Taiwan , 1998 .

[37]  T. Rockwell,et al.  Active tectonics at Wheeler Ridge, southern San Joaquin Valley, California , 1998 .

[38]  T. Harrison,et al.  Late Cenozoic tectonic evolution of the southern Chinese Tian Shan , 1998 .

[39]  F. Storti,et al.  Growth stratal architectures associated to decollement folds and fault-propagation folds. Inferences on fold kinematics , 1997 .

[40]  E. Sobel,et al.  Thrusting and exhumation around the margins of the western Tarim basin during the India‐Asia collision , 1997 .

[41]  P. Talling,et al.  Geomorphic evidence for tear faults accommodating lateral propagation of an active fault-bend fold, Wheeler Ridge, California , 1997 .

[42]  James Jackson,et al.  The structural evolution of active fault and fold systems in central Otago, New Zealand: evidence revealed by drainage patterns , 1996 .

[43]  B. Burchfiel,et al.  Quaternary Climate Change and the Formation of River Terraces across Growing Anticlines on the North Flank of the Tien Shan, China , 1994, The Journal of Geology.

[44]  H. Perroud,et al.  Paleomagnetism of Cretaceous red beds from Tadzhikistan and Cenozoic deformation due to India-Eurasia collision , 1994 .

[45]  J. Epard,et al.  Excess Area and Depth to Detachment , 1993 .

[46]  Peter Molnar,et al.  Geological and Geophysical Evidence for Deep Subduction of Continental Crust Beneath the Pamir , 1993 .

[47]  W. Lettis,et al.  Quaternary fold deformation associated with blind thrust faulting, Los Angeles Basin, California , 1993 .

[48]  M. Summerfield.  Tectonic geomorphology , 1991 .

[49]  T. Rockwell,et al.  Quaternary rate of folding of the Ventura Avenue anticline, western Transverse Ranges, southern California , 1988 .

[50]  E. Cowgill.  Cenozoic right-slip faulting along the eastern margin of the Pamir salient, northwestern China , 2010 .

[51]  K. Scharer,et al.  Kinematic models of fl uvial terraces over active detachment folds : Constraints on the growth mechanism of the Kashi-Atushi fold system , Chinese , 2006 .

[52]  C. Jie.  QUATERNARY DETACHMENT FOLDING OF THE MINGYAOLE ANTICLINE,SOUTHWESTERN TIAN SHAN , 2005 .

[53]  J. Chenc,et al.  Detachment folding in the Southwestern Tian Shan – Tarim foreland , China : shortening estimates and rates , 2004 .

[54]  X. An.  The Kinematics Characters of The Thrust-fold Belts Western Front Regions in Southern Tianshan ,China , 2000 .

[55]  George T. Chou,et al.  Rates of folding and faulting determined from growth strata , 1992 .