Geochronology and physical context of Oldowan site formation at Kanjera South, Kenya

AbstractOldowan sites in primary geological context are rare in the archaeological record. Here we describe the depositional environment of Oldowan occurrences at Kanjera South, Kenya, based on field descriptions and granulometric analysis. Excavations have recovered a large Oldowan artefact sample as well as the oldest substantial sample of archaeological fauna. The deposits at Kanjera South consist of 30 m of fluvial, colluvial and lacustrine sediments. Magneto- and biostratigraphy indicate the Kanjera South Member of the Kanjera Formation was deposited during 2.3–1.92 Ma, with 2.0 Ma being a likely age for the archaeological occurrences. Oldowan artefacts and associated fauna were deposited in the colluvial and alluvial silts and sands of beds KS1–3, in the margins of a lake basin. Field descriptions and granulometric analysis of the sediment fine fraction indicate that sediments from within the main archaeological horizon were emplaced as a combination of tractional and hyperconcentrated flows with limited evidence of debris-flow deposition. This style of deposition is unlikely to significantly erode or disturb the underlying surface, and therefore promotes preservation of surface archaeological accumulations. Hominins were repeatedly attracted to the site locale, and rapid sedimentation, minimal bone weathering and an absence of bone or artefact rounding further indicate that fossils and artefacts were quickly buried.

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Wreck-Site Formation Processes

10.1093/oxfordhb/9780199336005.013.0002 ◽

2012 ◽

Author(s):

Colin Martin

Keyword(s):

Physical Properties ◽

Site Formation ◽

Site Formation Processes ◽

Formation Processes ◽

Natural Processes ◽

Anthropogenic Inputs ◽

Physical Context ◽

Dynamic Phase ◽

Environmental Setting ◽

Essential Prerequisite

The environmental settings within which shipwrecks occur are matters of chance rather than of choice. It is primarily the wreck and not its physical context that is of consequence to nautical archaeologists. No two wreck-site formations are the same, since the complex and interacting variables that constitute the environmental setting, the nature of the ship, and the circumstances of its loss combine to create a set of attributes unique to each site. The dynamic phase, which begins with the event of shipwreck, is characterized by the wreck's status as an environmental anomaly. It is unstable, lacks integration with its surroundings, and is prone to further disintegration and dispersal by external influences. The chemical and physical properties of water cause reactions with the metals. Understanding these natural processes in the context of the distinctively anthropogenic inputs, this article characterizes archaeology as an essential prerequisite to the interpretation of any shipwreck.

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Recent seismic events preserved in lacustrine sediments from the SE Tibetan Plateau

10.5194/egusphere-egu2020-7557 ◽

2020 ◽

Author(s):

Yongbo Wang ◽

Xuezhi Ma ◽

Zhenyu Ni

Keyword(s):

Grain Size ◽

Tibetan Plateau ◽

Sediment Cores ◽

Lacustrine Sediments ◽

Size Composition ◽

Recurrence Time ◽

Seismic Events ◽

Lake Basin ◽

The Tibetan Plateau ◽

Fine Clay

Large earthquakes are regarded as important contributors to long-term erosion rates and considerable hazard to infrastructure and society, which were difficult to track because of the long recurrence time exceeding the time span of historical records. Geological records, especially the continuously accumulated lacustrine sediments, hold the potential to capture signals of prehistoric seismic events, which has been barely reported from the Tibetan Plateau. Here we present lacustrine sediment records recovered from Basom Tso in Southeastern Tibetan Plateau, in which two seismic events were preserved. Sediment lithology, grain size composition, magnetic susceptibility and XRF scanning induced element compositions showed dramatic variations in two turbidite-like sediment segments. Particularly, the grain size showed an abrupt increase at the bottom of the Turbidites which was followed by a fining-up pattern and covered by a fine clay cap, expressing similar sedimentary processes caused by the seiche effect triggered by seismic events. Consistent patterns were recorded in the element contents as well, i.e. obvious bias in the counts of Fe, Zr, Ti, Ca. In addition, scuh pattern were preserved in sediment cores from different part of the lake basin, indicating a basin wide event layer. Finally, according to the dating results from 137Cs and 14C, the two Turbidites were formed around 1950 A.D. and during the late18th/early 19th century respectively. Such information was further confirmed by historical earthquake records that Chayu Earthquake (M=8.6, 1950 A.D.) and Nyingchi Earthquake (M=6.75, 1845 A.D.) have possibly responsible for the slump of underwater sediments and the formation of these two turbidites.

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Subsurface Stone Lines, Stone Zones, Artifact-Manuport Layers, and Biomantles Produced by Bioturbation via Pocket Gophers (Thomomys Bottae)

American Antiquity ◽

10.2307/281712 ◽

1989 ◽

Vol 54 (2) ◽

pp. 370-389 ◽

Cited By ~ 82

Author(s):

Donald L. Johnson

Keyword(s):

Laboratory Tests ◽

Fine Fraction ◽

Archaeological Site ◽

Site Formation ◽

Maximum Diameter ◽

Field Observations ◽

Pocket Gophers ◽

Subsurface Zone ◽

Thomomys Bottae ◽

Gravelly Soil

A prominent subsurface zone (layer) of large stones with diameters greater than 6-7 cm occurs in gravelly soil on colluvial aprons in the Lompoc area of California. The soil is mounded and churned by botta pocket gophers (Thomomys bottae). Sedimentological analyses show that the soil within and above the stone zone—and within the gopher mounds—is relatively homogeneous in fine fraction and forms a biomantle. None of the mounds contained stones with long-axis diameters greater than the maximum diameter of gopher burrows, about 6-7 cm. Larger stones gradually subside and form a stone zone. Both field observations and laboratory tests confirm that gopher bioturbation produces stone zones in coarse gravelly soil. This finding, and similar findings in two other recent studies, have important implications for interpreting archaeological site formation, and for interpreting geologic-pedologic processes inasmuch as artifact layers (and nonartifact layers) in some sites entirely may be due to nonanthropic, nongeologic, postdepositional biological agents.

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Depositional environment of the Fort Member of the Jurasic Jaisalmer Formation, (western Rajasthan,.

Geologica Acta ◽

10.1344/geologicaacta2017.15.3.1 ◽

2017 ◽

Author(s):

F. AHMAD ◽

M.A QUASIM ◽

A.A GHAZNAVI ◽

Z. KHAN ◽

A.H.M AHMAD

Keyword(s):

Standard Deviation ◽

Field Data ◽

Depositional Environment ◽

Wide Spectrum ◽

High Energy ◽

Marine Environments ◽

Inner Shelf ◽

Granulometric Analysis ◽

Textural Parameters

Lithofacies and granulometric analysis were carried out to decipher the depositional environment of the Fort Member of the Jurassic Jaisalmer Formation. Based on field data nine lithofacies have been identified including trough cross-bedded sandstones, planar cross-bedded sandstones, matrix supported conglomerates, thinly bedded siltstone and sandstones, herringbone cross-bedded sandstones, wave rippled sandstones, laminated sandstones, hummocky cross-bedded sandstones, limestones and shales. Granulometric analysis of the sandstones samples has been carried out for their statistical and textural parameters. Bivariant plots of textural parameters such as graphic skewness versus graphic standard deviation and skewness versus standard deviation confirm the high energy (beach) origin of sandstones. These results suggest a wide spectrum of marine environments ranging from inner shelf to upper shoreface for the Fort Member sandstones.

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Radiocarbon Chronology of Late Glacial and Holocene Sedimentation and Water-Level Changes in the Area of the Gościąż Lake Basin

Radiocarbon ◽

10.1017/s0033822200040492 ◽

1994 ◽

Vol 36 (2) ◽

pp. 187-202 ◽

Cited By ~ 8

Author(s):

Anna Pazdur ◽

M. F. Pazdur ◽

Tomasz Goslar ◽

Bogumił Wicik ◽

Maurice Arnold

Keyword(s):

Climate Changes ◽

Global Climate ◽

Lacustrine Sediments ◽

Late Glacial ◽

Lake Basin ◽

Global Climate Changes ◽

Laminated Sediment ◽

Water Level Changes ◽

Late Glacial And Holocene ◽

Radiocarbon Chronology

We obtained 14C ages on samples of lake marl and other sediments from cores taken in Gościąż Lake and its environs. Comparison of 14C dates of bulk samples of laminated sediment with varve chronology and available AMS dates of terrestrial macrofossils indicates a reservoir correction of 2000 ± 120 yr for the basal series of lake sediments. 14C dates obtained on peat layers underlying the oldest lacustrine sediments in Gościąż and other lakes consistently locate the beginning of organogenic sedimentation in this area at ca. 13 ka bp. We distinguished three periods of lacustrine gyttja sedimentation in cores taken in Gościąż and adjacent lakes: 11.8–10.2 ka, 8–7 ka and 2.7–2.1 ka bp. From the 14C dates of lithological boundaries in these cores, we reconstruct a pattern of lake-level changes during the last 12 ka, remarkably similar to Swedish lakes and generally agreeing with available records from European and American lakes. The behavior of Gościąż Lake during the last 12 ka fairly well reflects global climate changes in the temperate zone during the Late Glacial and Holocene periods.

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A multi-proxy lacustrine record of last deglacial–early Holocene environmental variability in the lower Yangtze region from the Chaohu Lake Basin, eastern China

Quaternary Research ◽

10.1017/qua.2017.52 ◽

2017 ◽

Vol 88 (3) ◽

pp. 446-457 ◽

Cited By ~ 1

Author(s):

Houchun Guan ◽

Li Wu ◽

Jinzhe Zhang ◽

Shihao Shen ◽

Dongru Chu ◽

...

Keyword(s):

Lacustrine Sediments ◽

Cold Climate ◽

Early Holocene ◽

Chaohu Lake ◽

Lake Basin ◽

Chaohu Lake Basin ◽

Lower Yangtze Region ◽

Lower Yangtze ◽

The Chaohu Lake Basin ◽

Last Deglacial

AbstractThe Rb, Sr, and Ti content, Rb/Sr ratio, grain size, magnetic susceptibility, and magnetic fabric in sediments of the BZK1 core were utilized to reconstruct the evolution of the climatic environment in the Chaohu Lake Basin between the last deglacial and the early Holocene. Multi-proxy analyses indicate that lacustrine sediments in Chaohu Lake clearly record the Bølling-Allerød interstadial, the Younger Dryas event and dry-cold climate events occurring between 10.7 cal ka BP and 10.5 cal ka BP. At approximately 15.6–14.8 cal ka BP, the waters became deeper and the climate turned cool. The climate subsequently shifted to a relatively humid period and the lake was largest from 14.8 to 12.8 cal ka BP. From 12.8 to 11.7 cal ka BP, the climate abruptly turned dry and cold and the lake shrank to its lowest level. During 11.7–10.7 cal ka BP, the climate became relatively humid but, from approximately 10.7 to 10.5 cal ka BP, suddenly reverted to a dry and cold state. These climatic change records suggest that lacustrine sediments from the Chaohu Lake Basin in the lower Yangtze region responded actively to global climate changes, comparable with the environmental records from stalagmites and other lacustrine sediments in the region.

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KARAKTERISTIK ENDAPAN DANAU RAWA PENING DI MUARA INLET SUNGAI GALEH, KECAMATAN AMBARAWA, KABUPATEN SEMARANG

KURVATEK ◽

10.33579/krvtk.v5i1.1784 ◽

2020 ◽

Vol 5 (1) ◽

pp. 59-67

Author(s):

Setyo Pambudi ◽

Muhammad Fikri Abubakar

Keyword(s):

Shallow Lake ◽

Depositional Environment ◽

River Estuary ◽

Sedimentary Facies ◽

Deep Lake ◽

Scanning Method ◽

Clastic Sediments ◽

Granulometric Analysis ◽

Lacustrine Facies ◽

Current Mechanism

The Galeh River inlet estuary on Lake Rawa Pening is located in Ambarawa District, Semarang Regency. Sampling of Rawa Pening sediment at two points using modern coring methods. The coring results were observed and granulometric analysis was done using lazer scanning method with Master Sizer 2000. Core RWP-01 samples in the form of fine clastic sediments (Sand-Silt), reflecting the inlet river estuary environment in the hydrological lake system which is influenced by the fluvio-lacustrin process and showing characterizer of shallow lake facies. RWP-02 core samples in the form of fine-textured sediments (mud) rich in organic material, reflecting a relatively calm and stable depositional environment, formed by the density current mechanism that characterize the deep lake facies. The development of these sedimentary characters shows changes in sedimentary facies, namely shallow lake facies developing into clastical lake lacustrine into deep lake lacustrine facies.

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Late Pliocene Oldowan excavations at Kanjera South, Kenya

Antiquity ◽

10.1017/s0003598x00089365 ◽

2001 ◽

Vol 75 (290) ◽

pp. 809-810 ◽

Cited By ~ 7

Author(s):

Thomas Plummer ◽

Joseph Ferraro ◽

Peter Ditchfield ◽

Laura Bishop ◽

Richard Potts

Keyword(s):

Site Formation ◽

Site Formation Processes ◽

Formation Processes ◽

Large Mammal ◽

Late Pliocene ◽

Wide Range ◽

Kanjera South ◽

Adaptive Shifts ◽

Innovative Techniques ◽

Stone Artefact

The appearance of Oldowan sites c. 2.5 million years ago signals one of the most important adaptive shifts in human evolution. Large mammal u butchery, stone artefact manufacture and novel transport and discard behaviours led to the accumulation of the first recognized archaeological debris. Although the earliest instances of these behaviours are 2.5 million years ago, most of what we know about Oldowan palaeoecology and behaviour is derived from localities more than half a million years younger, particularly c. 1.8 million-year-old sites from Bed I Olduvai Gorge, Tanzania (Potts 1988). Sites from Kanjera South, Homa Peninsula, southwestern Kenya, yield dense concentrations of artefacts in association with the oldest (c. 2.2 million years) substantial sample of archaeological fauna known thus far from Africa. This study is the first to use a wide range of traditional and innovative techniques to investigate Oldowan hominin behaviour and site formation processes before 2 million years ago.

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Interglacial deposits at Bobbitshole, Ipswich

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1957.0006 ◽

1957 ◽

Vol 241 (676) ◽

pp. 1-31 ◽

Cited By ~ 64

Keyword(s):

Sea Level ◽

Lacustrine Sediments ◽

Interglacial Period ◽

Lake Basin ◽

Sea Level Changes ◽

Last Interglacial ◽

Marsh Vegetation ◽

Sandy Gravel ◽

North West ◽

Plant Remains

The stratigraphy and palaeobotany of fresh-water interglacial deposits at Bobbitshole, Ipswich, Suffolk, have been investigated. The interglacial deposits are shown to occupy a lake basin in a valley cut in the local plateau, which is partly formed by a chalky boulder clay assigned to the Gipping ice advance. In this basin was deposited a series of lacustrine sediments, first silt (probably of aeolian origin), then clay-mud and finally clay. These interglacial sediments are sealed unconformably by sandy gravel, probably deposited under cold conditions. Pollen diagrams and macroscopic plant remains from the interglacial deposits are described. They give evidence of the vegetational and climatic history during the first half of an interglacial period. The succession of pollen zones found is similar to that described from the Eemian (Last) Interglacial in north-west Europe, with which the interglacial is correlated. The Eemian pollen zones b , c , d , e and f which show the succession from birch- to pine- to oak-dominated forest, are all present. An analysis of the very abundant macroscopic plant remains, together with the pollen results, suggests a rapid amelioration of the climate at the beginning of the interglacial period, and in zone f , the final zone represented, there are indications of a summer warmth exceeding that of the present day in the area. The interglacial flora is particularly rich in aquatic plants, and an analysis of the abundance of each species indicates a vegetational succession, as the lake filled with sediment, from open-water to reed-swamp to marsh vegetation. The palaeobotany of the deposits is briefly compared with that of other interglacial deposits in Britain and on the continent. The correlation of the interglacial deposits with the continental Eemian (Last) Interglacial provides confirmation of the correlation of the Gipping ice advance with the Saale Glaciation of northern Germany, and indicates that the covering gravels are of Last Glaciation age. The interglacial deposits are partly below sea-level, and close to the tidal Orwell estuary. The significance of this for local relative land- and sea-level changes in and after the interglacial is discussed.

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Biomarker distributions as indicators for the depositional environment of lacustrine sediments in the Valjevo-Mionica basin (Serbia)

Geochemistry ◽

10.1016/j.chemer.2008.04.003 ◽

2008 ◽

Vol 68 (4) ◽

pp. 395-411 ◽

Cited By ~ 7

Author(s):

Aleksandra Šajnović ◽

Ksenija Stojanović ◽

Branimir Jovančićević ◽

Olga Cvetković

Keyword(s):

Depositional Environment ◽

Lacustrine Sediments

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