@article{fdi:010076525,
  title = {{G}eomorphologic and glacial evolution of the {C}achapoal and southern {M}aipo catchments in the {A}ndean {P}rincipal {C}ordillera, {C}entral {C}hile (34 degrees-35 degrees {S})},
  author = {{C}harrier, {R}. and {I}turrizaga, {L}. and {C}arretier, {S}{\'e}bastien and {R}egard, {V}.},
  editor = {},
  language = {{ENG}},
  abstract = {{W}e present here a reconstruction of the post late {M}iocene landscape evolution of the western slope of the {A}ndean {C}ordillera {P}rincipal near 34 degrees 20' {S}. {W}e base our analysis on the available geological information, a morphological characterization of the landform assemblages in the {C}achapoal and southern {M}aipo catchments, and the first {B}e-10 exposure ages for moraines in this area. {T}he {C}achapoal drainage basin is characterized by a variety of morphological features, like an elevated low-relief surface, volcanoes and lava flows on valley slopes, {U}-shaped valley sections, roches moutonnees, and large glaciated areas. {D}ifferent kinds of deposits have been included in the study, such as moraines, lacustrine and landslide deposits, and a well-developed system of fluvial terraces in the more distal part of the {C}achapoal catchment. {L}andslides are mostly developed on rocks of the late {E}ocene-early {M}iocene {A}banico {F}ormation. and are less frequent in outcrops of the overlying, early to middle {M}iocene {F}arellones {F}ormation. {W}e estimate that the lowest end moraine in the {C}achapoal catchment is located next to the locality {B}ocatoma {C}hacayes (similar to 950 m altitude), though covered by a major landslide. {N}o evidence exist for glacial deposits further down stream in this region. {L}ateral moraine ridges of the {C}achapoal {G}lacier at {L}os {C}errillos yielded {B}e-10 exposure ages of 20.3 +/- 2.9 and 21.9 +/- 5.3 ka that indicate they are associated with the {L}ast {G}lacial {M}aximum ({LGM}). {H}olocene moraines exist next to all glacier tongues. {O}f particular interest in this region is the 12 km-long debris-covered {C}achapoal {G}lacier, the longest valley glacier in the central {C}hilean {A}ndes, and its distal and proximal moraine deposits. {T}wo lateral moraines adjacent to the present-day {C}achapoal {G}lacier yielded exposure average ages of 13.5 +/- 2.4 ka for the external ridge, indicating the {Y}ounger {D}ryas, and 3.8 +/- 0.8 ka for the internal ridge, an age that coincides with the 4.2 ka global climatic event that marks the beginning of the {M}eghalayan {A}ge, at the end of the {H}olocene. {T}he large size of this moraine on both sides of the ice tongue indicates the great development of the glacier at that time. {S}ome of these ages coincide with ages obtained further north in the {M}aipo drainage basin, at the latitude of {S}antiago, and in the eastern flank of the cordillera, however, no pre-{LGM} deposits were found here, unlike the other mentioned regions. {T}his difference together with the much lower altitude of the {LGM} moraine deposits in the study region suggests that the {C}achapoal catchment is a transition zone to a more humid region further south, and indicates the great need for further reconnaissance and dating of glacial deposits in this {A}ndean region. {O}ur analysis of the geomorphological evolution is consistent with incision start for the {C}achapoal {V}alley in latest {M}iocene. {I}n this process, glacier incision was apparently not much effective until mid-{P}leistocene time, when volcanism was active in the higher regions of the mountain range covering areas not yet incised, whereas in the western {P}rincipal {C}ordillera lavas flowed in deeply incised valleys. {P}leistocene glaciers deepened and shaped the already incised valleys, which are presently mostly occupied by rivers.},
  keywords = {{P}ost-{M}iocene landscape evolution ; {B}e-10 exposure ages ; {LGM} ; {Y}ounger ; {D}ryas ; {C}achapoal drainage basin ; {P}rincipal {C}ordillera ; {C}entral {A}ndes ; {C}hile ; {CHILI} ; {ANDES}},
  booktitle = {},
  journal = {{A}ndean {G}eology},
  volume = {46},
  numero = {2},
  pages = {240--278},
  ISSN = {0718-7106},
  year = {2019},
  DOI = {10.5027/andgeo{V}46n2-3108},
  URL = {https://www.documentation.ird.fr/hor/fdi:010076525},
}