Not logged in
PANGAEA.
Data Publisher for Earth & Environmental Science

Gebregiorgis, Daniel; Deocampo, Daniel M; Longstaffe, Fred J; Simpson, Alexandra M; Ashley, Gail M; Beverly, Emily J; Delaney, Jeremy S; Cuadros, Javier (2020): Relative proportions of smectite and illite, and illite-smectite oxygen-isotope compositions (δ18OI-S) of 39 mudstone samples collected from a lacustrian section at Paleolake Olduvai. PANGAEA, https://doi.org/10.1594/PANGAEA.910866

Always quote above citation when using data! You can download the citation in several formats below.

RIS CitationBibTeX CitationShow MapGoogle Earth

Abstract:
Most clay minerals in sedimentary environments have traditionally been considered to be of detrital origin, but under certain conditions, authigenic clay minerals can form at low temperature through the transformation of precursor clays or as direct precipitates from lake-water. Such clay minerals can hold important information about the prevailing climatic conditions during the time of deposition. We present the first quantitative reconstruction of salinity in paleolake Olduvai based on the oxygen-isotope composition of authigenic clay minerals. We provide a framework illustrating that the isotopic signature of authigenic lacustrine clay minerals is related to the isotopic composition of paleo-waters, and hence to paleosalinity. This new paleosalinity proxy shows that the early Pleistocene East African monsoon was driven by combinations of precession and obliquity forcing, and subsequent changes in tropical SSTs. Such quantitative lacustrine paleosalinity estimates provides a new direction of research for modeling ecosystem change based on an ecologically relevant parameter.
Supplement to:
Gebregiorgis, Daniel; Deocampo, Daniel M; Longstaffe, Fred J; Simpson, Alexandra M; Ashley, Gail M; Beverly, Emily J; Delaney, Jeremy S; Cuadros, Javier (2020): Oxygen Isotopes in Authigenic Clay Minerals: Toward Building a Reliable Salinity Proxy. Geophysical Research Letters, 47(3), e2019GL085576, https://doi.org/10.1029/2019GL085576
Coverage:
Latitude: -2.963083 * Longitude: 35.313583
Date/Time Start: 1999-07-01T00:00:00 * Date/Time End: 1999-07-01T00:00:00
Event(s):
Olduvai-Paleolake * Latitude: -2.963083 * Longitude: 35.313583 * Date/Time: 1999-07-01T00:00:00 * Location: Africa, Tanzania * Method/Device: Sampling by hand (HAND) * Comment: hand-dug trench
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethod/DeviceComment
1Sample IDSample IDGebregiorgis, DanielStandard sample identification numbers (Deocampo et al., 2017, Geology; Gebregiorgis et al., 2020; GRL)
2Age modelAge modelkaGebregiorgis, DanielEstimated ages for 39 mudstone samples from a lacustrian section collected from Paleolake Olduvai
3IlliteIll%Gebregiorgis, DanielIllite percentages determined based on glycolated XRD patterns (See Gebregiorgis et al., 2020, GRL and references therein).
4SmectiteSme%Gebregiorgis, DanielSmectite percentages determined based on glycolated XRD patterns (See Gebregiorgis et al., 2020, GRL and references therein).
5δ18O, illite-smectiteδ18O Ill-Sme‰ SMOWGebregiorgis, Danielillite-smectite oxygen-isotope compositions (δ18OI-S) (VSMOW)
Size:
195 data points

Download Data

Download dataset as tab-delimited text (use the following character encoding: )

View dataset as HTML