@article{fdi:010079558,
  title = {{F}luvial terraces as quantitative markers of late {Q}uaternary detachment folding and creeping thrust faulting in the {P}eruvian {H}uallaga basin},
  author = {{V}iveen, {W}. and {B}aby, {P}atrice and {S}anjurjo-{S}anchez, {J}. and {H}urtado-{E}nriquez, {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n the western {H}uallaga basin, located in the {P}eruvian {S}ubandes, a series of nine fluvial terraces with elevations of up to 160 m above current floodplain level (+{FP}) were formed against the {B}iabo anticline. {T}he terraces are progressively more folded with age and terrace elevation and present growth strata, suggesting ongoing folding of the anticline. {O}ptically and {I}nfra{R}ed {S}timulated {L}uminescence ({OSL} and {IRSL}) dating of fluvial terrace sediments yielded ages of 10.8 +/- 0.7 ka for the {T}2, 24.2 +/- 2 ka for the {T}4 and 46 +/- 9 ka for the {T}7 terrace. {U}niform uplift rates of 2 mm a(-1) for the past 46 ka were calculated. {T}errace profiles and two new seismic profiles that cross the {B}iabo anticline longitudinally and transversally were used to calculate shortening rates of 2.6 mm a(-1) for the anticline over the past 46 ka. {O}ur calculations took into account potential contributions of detachment thrusting parallel to the {B}iabo fold and reverse tear faulting perpendicular to the fold tip as visible on the seismic sections. {A}maximumuplift rate of 0.62 mm a(-1) due to reverse thrusting of the {B}ellavista tear fault for the past 46 ka could have contributed to the overall uplift of the {B}ellavista terraces. {B}ased on trigonometric relationships, a reverse fault slip rate of 0.86 mm a(-1) and an age of 137 ka were calculated for this fault. {I}n the eastern part of the {H}uallaga basin, a series of two fluvial terraceswere formed with elevations of 13-15 m and 30 m + {FP} and with {OSL} ages of 6.9 +/- 0.7 ka for {T}1 and 30.2 +/- 3.1 ka for {T}2. {T}he interpretation of a third new seismic profile crossing the study area in combination with field observations and trigonometric relationships shows that the terraceswere formed by a complex system of oblique ramp and strike-slip faulting resulting in uplift and shortening rates of 1 mm a(-1) and 1.96 mm a(-1) between 30.2 ka and 6.9 ka respectively; and uplift and shortening rates of 2 mm a(-1) and 3.70 mm a(-1) from 6.9 ka until the present. {R}everse slip of the {S}hapaja oblique ramp, that was responsible for uplift of the terraces, was calculated at 2.19 mm a(-1) for the period 30.2 to 6.9 ka and 4.15 mm a(-1) from 6.9 ka until the present. {M}easured total slip in combination with the calculated slip rates allowed an age calculation of 181 ka for the {S}hapaja thrust ramp. {O}ur inferences showed that the studied tectonic structures absorb most of the present-day deformation in the {H}uallaga basin. {T}he calculated uplift and shortening rates are compatible with published, present-day crustal movement velocities, and {M}iocene to present shortening rates for various, studied sites of the tropical {S}ubandes and suggest that it is deforming at a relatively uniform rate. {T}he timing of sedimentation of the terrace sediments may have corresponded to periods of increased precipitation which occurred coeval with the {H}einrich events of the {N}orthern {H}emisphere. {T}errace records similar as ours have been described for other, tectonically highly active areas in the tropical {S}ubandes, but not in the tectonically less active {A}mazonian lowlands. {I}t is suggested that uplift rates of at least 1 mm a(-1) are needed to preserve suborbital climate cycles as individual terraces. {T}he tropical {S}ubandes could therefore be a new key area to investigate the interactions between tectonics, suborbital climate forcing and fluvial response during the late {Q}uaternary.},
  keywords = {{A}mazon basin ; {A}ndes ; {F}luvial terraces ; {H}einrich events ; {C}reeping faults ; {OSL} dating ; {PEROU} ; {ANDES} ; {HUALLAGA} {BASSIN}},
  booktitle = {},
  journal = {{G}eomorphology},
  volume = {367},
  numero = {},
  pages = {107315 [23 ]},
  ISSN = {0169-555{X}},
  year = {2020},
  DOI = {10.1016/j.geomorph.2020.107315},
  URL = {https://www.documentation.ird.fr/hor/fdi:010079558},
}