Open AccessOrbitally‐Tuned Sr Isotope Chemostratigraphy for the Late Middle to Late Miocene
Author(s) -
Martin E. E.,
Shackleton N. J.,
Zachos J. C.,
Flower B. P.
Publication year - 1999
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1029/1998pa900008
Subject(s) - geology , chemostratigraphy , paleontology , foraminifera , magnetostratigraphy , isotope , northern hemisphere , late miocene , isotopes of oxygen , isotopes of carbon , paleomagnetism , oceanography , geochemistry , benthic zone , atmospheric sciences , physics , quantum mechanics , structural basin
We present a Sr chemostratigraphic reference section for the late middle to late Miocene (14–5 Ma) from Ocean Drilling Program site 926 on the Ceara Rise. This site combines a precise, orbitally tuned timescale with a high sedimentation rate (15 m/m.y.), continuous deposition, and excellent biostratigraphic control. The Sr isotope curve is based on measurements of cleaned, planktonic foraminifera at 100–200 kyr sample intervals and it illustrates periods of rapid change in 87 Sr/ 86 Sr alternating with periods of little change. Chemostratigraphically‐defined ages for these intervals can be determined within +/−0.8 m.y. and +/−1.6 m.y. respectively. There is excellent correlation with the published curve for site 588 [ Hodell and Woodruff , 1994]; however the curve for site 747 [ Oslick et al. , 1994] exhibits less structure, which may be due to small errors in age estimates related to slow sedimentation rates, high‐latitude fauna and an interval of complicated magnetics. Late Miocene data compare favorably with data from site 758 [ Farrell et al. , 1995].