Evolution of crustal thickening in the central Andes, Bolivia

Nathan Eichelberger, Nadine McQuarrie, Jamie Ryan, Bobak Karimi, Susan Beck, George Zandt

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Paleoelevation histories from the central Andes in Bolivia have suggested that the geodynamic evolution of the region has been punctuated by periods of large-scale lithospheric removal that drive rapid increases in elevation at the surface. Here, we evaluate viable times and locations of material loss using a map-view reconstruction of the Bolivian orocline displacement field to forward-model predicted crustal thicknesses. Two volumetric models are presented that test assumed pre-deformation crustal thicknesses of 35 km and 40 km. Both models predict that modern crustal thicknesses were achieved first in the northern Eastern Cordillera (EC) by 30-20 Ma but remained below modern in the southern EC until ≤10 Ma. The Altiplano is predicted to have achieved modern crustal thickness after 10 Ma but only with a pre-deformation thickness of 50 km, including 10 km of sediment. At the final stage, the models predict 8-25% regional excess crustal volume compared to modern thickness, largely concentrated in the northern EC. The excess predicted volume from 20 to 0 Ma can be accounted for by: 1) crustal flow to the WC and/or Peru, 2) localized removal of the lower crust, or 3) a combination of the two. Only models with initial crustal thicknesses >35 km predict excess volumes sufficient to account for potential crustal thickness deficits in Peru and allow for lower crustal loss. However, both initial thickness models predict that modern crustal thicknesses were achieved over the same time periods that paleoelevation histories indicate the development of modern elevations. Localized removal of lower crust is only necessary in the northern EC where crustal thickness exceeds modern by 20 Ma, prior to paleoelevation estimates of modern elevations by 15 Ma. In the Altiplano, crustal thicknesses match modern values at 10 Ma and can only exceed modern values by 5 Ma, post-dating when modern elevations were thought to have been established. Collectively, these models predict that the timing of crustal thickening is consistent with paleoelevation data without requiring large-scale removal of lower crust and mantle lithosphere.

Original languageEnglish (US)
Pages (from-to)191-203
Number of pages13
JournalEarth and Planetary Science Letters
Volume426
DOIs
StatePublished - Sep 5 2015

Fingerprint

Bolivia
crustal thickening
crustal thickness
cordillera
Descaling
lower crust
Peru
crusts
Geodynamics
histories
lower mantle
Sediments
history
geodynamics
lithosphere
dating

Keywords

  • Altiplano
  • Andean plateau
  • Crustal flow
  • Crustal thickness
  • Orocline
  • Shortening

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Evolution of crustal thickening in the central Andes, Bolivia. / Eichelberger, Nathan; McQuarrie, Nadine; Ryan, Jamie; Karimi, Bobak; Beck, Susan; Zandt, George.

In: Earth and Planetary Science Letters, Vol. 426, 05.09.2015, p. 191-203.

Research output: Contribution to journalArticle

Eichelberger, Nathan ; McQuarrie, Nadine ; Ryan, Jamie ; Karimi, Bobak ; Beck, Susan ; Zandt, George. / Evolution of crustal thickening in the central Andes, Bolivia. In: Earth and Planetary Science Letters. 2015 ; Vol. 426. pp. 191-203.
@article{1230fcfdabca4cdcb99c0d558097d5cf,
title = "Evolution of crustal thickening in the central Andes, Bolivia",
abstract = "Paleoelevation histories from the central Andes in Bolivia have suggested that the geodynamic evolution of the region has been punctuated by periods of large-scale lithospheric removal that drive rapid increases in elevation at the surface. Here, we evaluate viable times and locations of material loss using a map-view reconstruction of the Bolivian orocline displacement field to forward-model predicted crustal thicknesses. Two volumetric models are presented that test assumed pre-deformation crustal thicknesses of 35 km and 40 km. Both models predict that modern crustal thicknesses were achieved first in the northern Eastern Cordillera (EC) by 30-20 Ma but remained below modern in the southern EC until ≤10 Ma. The Altiplano is predicted to have achieved modern crustal thickness after 10 Ma but only with a pre-deformation thickness of 50 km, including 10 km of sediment. At the final stage, the models predict 8-25{\%} regional excess crustal volume compared to modern thickness, largely concentrated in the northern EC. The excess predicted volume from 20 to 0 Ma can be accounted for by: 1) crustal flow to the WC and/or Peru, 2) localized removal of the lower crust, or 3) a combination of the two. Only models with initial crustal thicknesses >35 km predict excess volumes sufficient to account for potential crustal thickness deficits in Peru and allow for lower crustal loss. However, both initial thickness models predict that modern crustal thicknesses were achieved over the same time periods that paleoelevation histories indicate the development of modern elevations. Localized removal of lower crust is only necessary in the northern EC where crustal thickness exceeds modern by 20 Ma, prior to paleoelevation estimates of modern elevations by 15 Ma. In the Altiplano, crustal thicknesses match modern values at 10 Ma and can only exceed modern values by 5 Ma, post-dating when modern elevations were thought to have been established. Collectively, these models predict that the timing of crustal thickening is consistent with paleoelevation data without requiring large-scale removal of lower crust and mantle lithosphere.",
keywords = "Altiplano, Andean plateau, Crustal flow, Crustal thickness, Orocline, Shortening",
author = "Nathan Eichelberger and Nadine McQuarrie and Jamie Ryan and Bobak Karimi and Susan Beck and George Zandt",
year = "2015",
month = "9",
day = "5",
doi = "10.1016/j.epsl.2015.06.035",
language = "English (US)",
volume = "426",
pages = "191--203",
journal = "Earth and Planetary Sciences Letters",
issn = "0012-821X",
publisher = "Elsevier",

}

TY - JOUR

T1 - Evolution of crustal thickening in the central Andes, Bolivia

AU - Eichelberger, Nathan

AU - McQuarrie, Nadine

AU - Ryan, Jamie

AU - Karimi, Bobak

AU - Beck, Susan

AU - Zandt, George

PY - 2015/9/5

Y1 - 2015/9/5

N2 - Paleoelevation histories from the central Andes in Bolivia have suggested that the geodynamic evolution of the region has been punctuated by periods of large-scale lithospheric removal that drive rapid increases in elevation at the surface. Here, we evaluate viable times and locations of material loss using a map-view reconstruction of the Bolivian orocline displacement field to forward-model predicted crustal thicknesses. Two volumetric models are presented that test assumed pre-deformation crustal thicknesses of 35 km and 40 km. Both models predict that modern crustal thicknesses were achieved first in the northern Eastern Cordillera (EC) by 30-20 Ma but remained below modern in the southern EC until ≤10 Ma. The Altiplano is predicted to have achieved modern crustal thickness after 10 Ma but only with a pre-deformation thickness of 50 km, including 10 km of sediment. At the final stage, the models predict 8-25% regional excess crustal volume compared to modern thickness, largely concentrated in the northern EC. The excess predicted volume from 20 to 0 Ma can be accounted for by: 1) crustal flow to the WC and/or Peru, 2) localized removal of the lower crust, or 3) a combination of the two. Only models with initial crustal thicknesses >35 km predict excess volumes sufficient to account for potential crustal thickness deficits in Peru and allow for lower crustal loss. However, both initial thickness models predict that modern crustal thicknesses were achieved over the same time periods that paleoelevation histories indicate the development of modern elevations. Localized removal of lower crust is only necessary in the northern EC where crustal thickness exceeds modern by 20 Ma, prior to paleoelevation estimates of modern elevations by 15 Ma. In the Altiplano, crustal thicknesses match modern values at 10 Ma and can only exceed modern values by 5 Ma, post-dating when modern elevations were thought to have been established. Collectively, these models predict that the timing of crustal thickening is consistent with paleoelevation data without requiring large-scale removal of lower crust and mantle lithosphere.

AB - Paleoelevation histories from the central Andes in Bolivia have suggested that the geodynamic evolution of the region has been punctuated by periods of large-scale lithospheric removal that drive rapid increases in elevation at the surface. Here, we evaluate viable times and locations of material loss using a map-view reconstruction of the Bolivian orocline displacement field to forward-model predicted crustal thicknesses. Two volumetric models are presented that test assumed pre-deformation crustal thicknesses of 35 km and 40 km. Both models predict that modern crustal thicknesses were achieved first in the northern Eastern Cordillera (EC) by 30-20 Ma but remained below modern in the southern EC until ≤10 Ma. The Altiplano is predicted to have achieved modern crustal thickness after 10 Ma but only with a pre-deformation thickness of 50 km, including 10 km of sediment. At the final stage, the models predict 8-25% regional excess crustal volume compared to modern thickness, largely concentrated in the northern EC. The excess predicted volume from 20 to 0 Ma can be accounted for by: 1) crustal flow to the WC and/or Peru, 2) localized removal of the lower crust, or 3) a combination of the two. Only models with initial crustal thicknesses >35 km predict excess volumes sufficient to account for potential crustal thickness deficits in Peru and allow for lower crustal loss. However, both initial thickness models predict that modern crustal thicknesses were achieved over the same time periods that paleoelevation histories indicate the development of modern elevations. Localized removal of lower crust is only necessary in the northern EC where crustal thickness exceeds modern by 20 Ma, prior to paleoelevation estimates of modern elevations by 15 Ma. In the Altiplano, crustal thicknesses match modern values at 10 Ma and can only exceed modern values by 5 Ma, post-dating when modern elevations were thought to have been established. Collectively, these models predict that the timing of crustal thickening is consistent with paleoelevation data without requiring large-scale removal of lower crust and mantle lithosphere.

KW - Altiplano

KW - Andean plateau

KW - Crustal flow

KW - Crustal thickness

KW - Orocline

KW - Shortening

UR - http://www.scopus.com/inward/record.url?scp=84936867712&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84936867712&partnerID=8YFLogxK

U2 - 10.1016/j.epsl.2015.06.035

DO - 10.1016/j.epsl.2015.06.035

M3 - Article

AN - SCOPUS:84936867712

VL - 426

SP - 191

EP - 203

JO - Earth and Planetary Sciences Letters

JF - Earth and Planetary Sciences Letters

SN - 0012-821X

ER -