Upper Cenozoic chronostratigraphy of the southwestern Amazon Basin

Citation
Ke. Campbell et al., Upper Cenozoic chronostratigraphy of the southwestern Amazon Basin, GEOLOGY, 29(7), 2001, pp. 595-598
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
GEOLOGY
ISSN journal
0091-7613 → ACNP
Volume
29
Issue
7
Year of publication
2001
Pages
595 - 598
Database
ISI
SICI code
0091-7613(200107)29:7<595:UCCOTS>2.0.ZU;2-5
Abstract
The lack of numerical age dates for upper Cenozoic strata of the Amazon Bas in has prevented resolution of its geologic history and accurate dating of important paleofaunas. Here we present results of magnetostratigraphy and A r-40/Ar-39 dating of two volcanic ash deposits from the Madre de Dies Forma tion of eastern Peru, The two ash ages, 9.01 +/- 0.28 Ma and 3.12 +/- 0.02 Ma, provide the first numerical age data necessary for accurate interpretat ion of late Tertiary sedimentation in Amazonia and establish approximate ti me constraints for the last major cycle of Cenozoic deposition within the s outhwestern Amazon Basin. The older ash age also provides a minimum age for numerous Amazonian paleofaunas, which allows a more definitive correlation of these paleofaunas with those in other regions of South America.