TY - JOUR

T1 - Larger benthic foraminifera from the Middle Eocene to Oligocene of Tanzania

AU - Cotton, Laura J.

AU - Pearson, Paul N.

PY - 2012

Y1 - 2012

N2 - Larger benthic foraminifera (LBF) are common and diverse throughout the Paleogene sediments of southern Tanzania, but have previously been little studied. A recent programme of onshore drilling known as the Tanzania Drilling Project has recovered large proportion of this succession for palaeoclimatic and palaeontological study. The sediment is largely a hemipelagic clay with secondary gravity sediment flow limestones and calcarenites. LBF occur concentrated in the secondary beds and are present in some clay horizons. Planktonic foraminiferal, nannofossil and, in some cases, stable isotope studies of the clays allow the larger benthic foraminiferal ranges to be tied to global stratigraphy. Here we use nine of these drill sites to examine the LBF from the Middle Eocene to Oligocene. Within this interval several global turnover events of long-ranging and widespread LBF genera are known to occur. However, problems with biostratigraphy mean the exact timing and therefore mechanisms remain uncertain. Our study shows that ranges of Tanzanian LBF genera are within known global ranges. Additionally, there is a change in the LBF assemblage with a number of local first and last occurrences of genera during the Bartonian, which may have potential links to the onset of the Mid Eocene Climatic Optimum.

AB - Larger benthic foraminifera (LBF) are common and diverse throughout the Paleogene sediments of southern Tanzania, but have previously been little studied. A recent programme of onshore drilling known as the Tanzania Drilling Project has recovered large proportion of this succession for palaeoclimatic and palaeontological study. The sediment is largely a hemipelagic clay with secondary gravity sediment flow limestones and calcarenites. LBF occur concentrated in the secondary beds and are present in some clay horizons. Planktonic foraminiferal, nannofossil and, in some cases, stable isotope studies of the clays allow the larger benthic foraminiferal ranges to be tied to global stratigraphy. Here we use nine of these drill sites to examine the LBF from the Middle Eocene to Oligocene. Within this interval several global turnover events of long-ranging and widespread LBF genera are known to occur. However, problems with biostratigraphy mean the exact timing and therefore mechanisms remain uncertain. Our study shows that ranges of Tanzanian LBF genera are within known global ranges. Additionally, there is a change in the LBF assemblage with a number of local first and last occurrences of genera during the Bartonian, which may have potential links to the onset of the Mid Eocene Climatic Optimum.

KW - Eocene

KW - Larger foraminifera

KW - MECO

KW - Oligocene

KW - Tanzania

M3 - Journal article

AN - SCOPUS:84863575720

VL - 105

SP - 189

EP - 199

JO - Austrian Journal of Earth Sciences

JF - Austrian Journal of Earth Sciences

SN - 0251-7493

IS - 1

ER -