Paleomagnetic determinations of vertical-axis tectonic rotations from Late Cretaceous and Paleocene strata of Bolivia

Structural development of the Altiplano during the past 10 m.y. involved crustal thickening and enhanced curvature of the central Andes. Oroclinal bending of 30° explains reasonably the pattern of vertical-axis rotations observed from units with ages 10 to 30 Ma. New paleomagnetic data from Late Cre...

Full description

Saved in:
Bibliographic Details
Published in:Geology (Boulder) 1995-09, Vol.23 (9), p.799-802
Main Authors: Butler, R. F, Richards, D. R, Sempere, T, Marshall, L. G
Format: Article
Language:English
Subjects:
Altiplano
Andes
Bolivia
Cenozoic
Central Andes
characteristic remanent magnetization
clastic rocks
Cretaceous
crustal thickening
dikes
El Molino Formation
Geological time
intrusions
La Palca Bolivia
Laguna Umayo Bolivia
Lake Titicaca
lower Paleocene
Maestrichtian
magnetization
Mesozoic
natural remanent magnetization
oroclines
orogenic belts
orogeny
Paleocene
Paleogene
paleomagnetism
Plate tectonics
red beds
remanent magnetization
rotation
Santa Lucia Formation
sedimentary rocks
Senonian
South America
Stratigraphy
Structural geology
Sucusuma Bolivia
tectonics
Tertiary
Umayo Formation
Upper Cretaceous
vertical orientation
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Structural development of the Altiplano during the past 10 m.y. involved crustal thickening and enhanced curvature of the central Andes. Oroclinal bending of 30° explains reasonably the pattern of vertical-axis rotations observed from units with ages 10 to 30 Ma. New paleomagnetic data from Late Cretaceous through Paleocene strata of southeastern Peru and the Eastern Cordillera of Bolivia document rotations that are also counterclockwise on the north limb of the orocline and clockwise on the south limb. However, the rotations of units with ages 30 to 70 Ma are more variable; nearby areas have undergone differential vertical-axis rotations of up to 60°. These larger rotations that have affected 30-70 Ma units in the central Andes may represent (1) local rotations during late Oligocene to present orogeny, (2) local rotations during Eocene orogeny, and/or (3) oroclinal bending during Eocene orogeny.
ISSN:0091-7613
1943-2682
DOI:10.1130/0091-7613(1995)023<0799:PDOVAT>2.3.CO;2