The Olduvai Gorge Coring Project: Drilling high resolution palaeoclimatic and palaeoenvironmental archives to constrain hominin evolution

Abstract Dark organic-rich layers (sapropels) have accumulated in Mediterranean sediments since the Miocene due to deep-sea dysoxia and enhanced carbon burial at times of intensified North African run-off during ‘Green’ Sahara Periods (GSPs). The existence of orbital precession-dominated Saharan aridity/humidity cycles is well known, but lack of long-term, high-resolution records hinders understanding of their precise relationships with environmental and hominin evolution. Here we present continuous, high-resolution geochemical and environmental magnetic records for the Eastern Mediterranean that span the past 5.2 million years, which reveal that organic burial in sapropels intensified 3.2 Myr ago. We deduce that fluvial terrigenous sediment inputs during GSPs doubled abruptly at this time, whereas monsoon run-off intensity remained relatively constant. We attribute the increase in sediment mobilisation to an abrupt non-linear North African landscape response associated with a major increase in arid:humid contrasts between GSPs and intervening dry periods. This likely limited hominin (and other animal) inhabitation of, and migration through, the Sahara region to GSPs only.

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Geochemical “fingerprints” for Olduvai Gorge Bed II tuffs and implications for the Oldowan–Acheulean transition

Quaternary Research ◽

10.1016/j.yqres.2015.10.005 ◽

2016 ◽

Vol 85 (1) ◽

pp. 147-158 ◽

Cited By ~ 28

Author(s):

Lindsay J. McHenry ◽

Jackson K. Njau ◽

Ignacio de la Torre ◽

Michael C. Pante

Keyword(s):

High Resolution ◽

Electron Probe Microanalysis ◽

Mineral Assemblage ◽

Electron Probe ◽

Early Pleistocene ◽

Olduvai Gorge ◽

Critical Part ◽

Homo Habilis ◽

Arid Conditions ◽

Stratigraphic Position

Bed II is a critical part of early Pleistocene Olduvai Gorge, Tanzania. Its deposits include transitions from humid to more arid conditions (with associated faunal changes), from Homo habilis to erectus, and from Oldowan to Acheulean technology. Bed II (~ 1.8–1.2 Ma) is stratigraphically and environmentally complex, with facies changes, faulting, and unconformities, making site-to-site correlation over the ~ 20 km of exposure difficult. Bed II tuffs are thinner, less evenly preserved, and more reworked than those of Bed I. Five marker tuffs (Tuffs IIA–IID, Bird Print Tuff (BPT)), plus local tephra, were collected from multiple sites and characterized using stratigraphic position, mineral assemblage, and electron probe microanalysis of phenocryst (feldspar, hornblende, augite, titanomagnetite) and glass (where available) composition. Lowermost Bed II tuffs are dominantly nephelinitic, Middle Bed II tuffs (BPT, Tuff IIC) have basaltic components, and upper Bed II Tuff IID is trachytic. The BPT and Tuff IID are identified widely using phenocryst compositions (high-Ca plagioclase and high-Ti hornblende, respectively), though IID was originally (Hay, 1976) misidentified as Tuff IIC at Loc 91 (SHK Annexe) in the Side Gorge. This work helps establish a high-resolution basin-wide paleolandscape context for the Oldowan–Acheulean transition and helps link hominin, faunal and archaeological records.

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PALEOECOLOGICAL RESPONSES TO LACUSTRINE VARIABILITY IN OLDUVAI GORGE, TANZANIA AND ITS IMPLICATIONS ON HOMININ EVOLUTION

10.1130/abs/2019am-335402 ◽

2019 ◽

Author(s):

Danielle M. Peltier ◽

◽

Edward W. Herrmann ◽

Jackson K. Njau

Keyword(s):

Olduvai Gorge ◽

Hominin Evolution

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Use of single-grain geochemistry of cryptic tuffs and volcaniclastic sandstones improves the tephrostratigraphic framework of Olduvai Gorge, Tanzania

Quaternary Research ◽

10.1016/j.yqres.2013.05.006 ◽

2013 ◽

Vol 80 (2) ◽

pp. 235-249 ◽

Cited By ~ 7

Author(s):

Lindsay J. McHenry ◽

Harald Stollhofen ◽

Ian G. Stanistreet

Keyword(s):

High Resolution ◽

Olduvai Gorge ◽

Equivalent Material ◽

Geochemical Composition ◽

Single Grain ◽

Mineral Compositions ◽

Land Surfaces ◽

Potential Tool

Single-grain geochemical composition of volcaniclastic sandstones can be a potential tool to improve correlations of mixed pyroclastic/epiclastic deposits. To test this, trachytic tuffs of the paleoanthropologically important FLK, FLK N, and FLK NN sites of Pleistocene Olduvai Gorge Bed I (Tanzania) are used as an established tephrostratigraphic framework against which to test volcaniclastic sandstone correlations. Fluvio-lacustrine sandstones and tuff samples were collected from eight archeological trenches between Tuffs IB and ID across a 500-m transect, including Leakey's famous Zinjanthropus (FLK) and OH 7/OH 8 (FLK NN) sites. A previously Tephrostratigraphy unknown, thin, fine, mineralogically unique, black trachyandesitic fallout ash was discovered below Tuff IC. Compositions of individual augite, feldspar and titanomagnetite grains from sandstones between Tuffs IB and IC reveal some IB-equivalent material, and a new compositional assemblage distinct from the sandwiching marker tuffs. Mineral compositions of the “tripartite” volcaniclastic sandstone between Tuffs IC and ID are similar to ID. Volcaniclastic sandstone grain fingerprints further refine correlations between fluvio-lacustrine sections within the area, providing support for proposed high-resolution stratigraphic reconstruction of the Zinjanthropus and OH 7/OH 8 land surfaces. This method might be applied to other sections where pyroclastic particles are admixed but distinct tuffs are not preserved.

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Microbial biomarkers reveal a hydrothermally active landscape at Olduvai Gorge at the dawn of the Acheulean, 1.7 Ma

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2004532117 ◽

2020 ◽

Vol 117 (40) ◽

pp. 24720-24728

Author(s):

Ainara Sistiaga ◽

Fatima Husain ◽

David Uribelarrea ◽

David M. Martín-Perea ◽

Troy Ferland ◽

...

Keyword(s):

Molecular Structures ◽

Lipid Biomarkers ◽

Olduvai Gorge ◽

Edible Plants ◽

Hominin Evolution ◽

Microbial Biomarkers ◽

Dynamic Landscape ◽

Ancient Plants ◽

The Impact ◽

The Relationship

Landscape-scale reconstructions of ancient environments within the cradle of humanity may reveal insights into the relationship between early hominins and the changing resources around them. Many studies of Olduvai Gorge during Pliocene–Pleistocene times have revealed the presence of precession-driven wet–dry cycles atop a general aridification trend, though may underestimate the impact of local-scale conditions on early hominins, who likely experienced a varied and more dynamic landscape. Fossil lipid biomarkers from ancient plants and microbes encode information about their surroundings via their molecular structures and composition, and thus can shed light on past environments. Here, we employ fossil lipid biomarkers to study the paleolandscape at Olduvai Gorge at the emergence of the Acheulean technology, 1.7 Ma, through the Lower Augitic Sandstones layer. In the context of the expansion of savanna grasslands, our results represent a resource-rich mosaic ecosystem populated by groundwater-fed rivers, aquatic plants, angiosperm shrublands, and edible plants. Evidence of a geothermally active landscape is reported via an unusual biomarker distribution consistent with the presence of hydrothermal features seen today at Yellowstone National Park. The study of hydrothermalism in ancient settings and its impact on hominin evolution has not been addressed before, although the association of thermal springs in the proximity of archaeological sites documented here can also be found at other localities. The hydrothermal features and resources present at Olduvai Gorge may have allowed early hominins to thermally process edible plants and meat, supporting the possibility of a prefire stage of human evolution.

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Observations of the spatial structure of interstellar hydrogen

Symposium - International Astronomical Union ◽

10.1017/s007418090010066x ◽

1967 ◽

Vol 31 ◽

pp. 45-46

Author(s):

Carl Heiles

Keyword(s):

High Resolution ◽

Spatial Structure ◽

Velocity Dispersion ◽

Temperature Variations

High-resolution 21-cm line observations in a region aroundlII= 120°,b11= +15°, have revealed four types of structure in the interstellar hydrogen: a smooth background, large sheets of density 2 atoms cm-3, clouds occurring mostly in groups, and ‘Cloudlets’ of a few solar masses and a few parsecs in size; the velocity dispersion in the Cloudlets is only 1 km/sec. Strong temperature variations in the gas are in evidence.

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Combining integrated systems-biology approaches with intervention-based experimental design provides a higher-resolution path forward for microbiome research

Behavioral and Brain Sciences ◽

10.1017/s0140525x18002911 ◽

2019 ◽

Vol 42 ◽

Author(s):

J. Alfredo Blakeley-Ruiz ◽

Carlee S. McClintock ◽

Ralph Lydic ◽

Helen A. Baghdoyan ◽

James J. Choo ◽

...

Keyword(s):

Systems Biology ◽

High Resolution ◽

Experimental Design ◽

Integrated Systems ◽

Microbiome Research ◽

Constructive Criticism

Abstract The Hooks et al. review of microbiota-gut-brain (MGB) literature provides a constructive criticism of the general approaches encompassing MGB research. This commentary extends their review by: (a) highlighting capabilities of advanced systems-biology “-omics” techniques for microbiome research and (b) recommending that combining these high-resolution techniques with intervention-based experimental design may be the path forward for future MGB research.

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Very High Resolution Analysis of the Dynamics of a Coronal Plasmoid

International Astronomical Union Colloquium ◽

10.1017/s0252921100026117 ◽

1994 ◽

Vol 144 ◽

pp. 593-596

Author(s):

O. Bouchard ◽

S. Koutchmy ◽

L. November ◽

J.-C. Vial ◽

J. B. Zirker

Keyword(s):

High Resolution ◽

Solar Eclipse ◽

Total Solar Eclipse ◽

Field Of View ◽

Small Field ◽

High Resolution Analysis ◽

Ccd Observations ◽

Resolution Analysis ◽

Very High ◽

Small Field Of View

AbstractWe present the results of the analysis of a movie taken over a small field of view in the intermediate corona at a spatial resolution of 0.5“, a temporal resolution of 1 s and a spectral passband of 7 nm. These CCD observations were made at the prime focus of the 3.6 m aperture CFHT telescope during the 1991 total solar eclipse.

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FeXIV Line Emission Polarization of the July 11, 1991 Solar Corona

International Astronomical Union Colloquium ◽

10.1017/s0252921100026002 ◽

1994 ◽

Vol 144 ◽

pp. 541-547

Author(s):

J. Sýkora ◽

J. Rybák ◽

P. Ambrož

Keyword(s):

High Resolution ◽

Solar Corona ◽

Emission Line ◽

Solar Eclipse ◽

White Light ◽

Preliminary Analysis ◽

Line Emission ◽

Total Solar Eclipse ◽

Degree Of Polarization ◽

High Resolution Images

AbstractHigh resolution images, obtained during July 11, 1991 total solar eclipse, allowed us to estimate the degree of solar corona polarization in the light of FeXIV 530.3 nm emission line and in the white light, as well. Very preliminary analysis reveals remarkable differences in the degree of polarization for both sets of data, particularly as for level of polarization and its distribution around the Sun’s limb.

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