Premium
Calibration of the Albian/Cenomanian Boundary by Ammonite Biostratigraphy: U.S. Western Interior
Author(s) -
SCOTT Robert W.
Publication year - 2007
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2007.tb01017.x
Subject(s) - ammonite , cenomanian , biostratigraphy , geology , paleontology , boundary (topology) , calibration , radiometric dating , cretaceous , stage (stratigraphy) , statistics , mathematical analysis , mathematics
Calibration of numerical ages to the geological time scale is a long scientific pursuit that requires the integration of multiple data sets. A case study of the Albian/Cenomanian stage boundary, also the Lower/Upper Cretaceous series boundary, illustrates the calibration process. The numerical age of this boundary has shifted from 96 Ma to 99 Ma over a time span of nearly fifty years. Re‐calibration resulted first from improvements in radiometric dating, and later from inferences about ammonite phylogeny, and most recently from radiometric dates of newly discovered volcanic beds interbedded with diagnostic guide fossils. However, the calibration process continues with study of cosmopolitan dinoflagellates.