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Featured researches published by Mark Stephens.


Asian Perspectives | 2005

Past human activity and geomorphological change in a guano-rich tropical cave mouth: initial interpretations of the Late Quaternary Succession in the Great Cave of Niah, Sarawak

Dd Gilbertson; Michael I. Bird; Chris Hunt; Sue McLaren; Richard Mani Banda; Brian Pyatt; James Rose; Mark Stephens

This paper presents initial interpretations of the processes and events responsible for the late Quaternary sequence in the West Mouth of the Great Cave of Niah, in the hot and humid lowland rainforest and swamp forest of Sarawak in Malaysian Borneo. It evaluates the geomorphological context of the site within the known pattern of rapid late Quaternary climate change. Attention is given to the proximity to the sea and the likelihood of humid tropical or cooler drier conditions. The stratigraphic succession is described and four units or lithofacies (2C, 2, 3 and 4) are recognized as being of particular geomorphological and archaeological importance. The key processes operating within the site are the accumulation and subsequent failure and flow of bat and bird guano, hillslope colluviation, and ephemeral stream flow and pond development. Units 2C and 2 contain the critical archaeology, including the Deep Skull from an anatomically modern human, discovered by Tom Harrisson. These were formed by colluviation from a complex cave-mouth rampart and stream flow from within the cave. The stream transported fine-grained sediment to a shallow pond, and both the stream and pond deposits show evidence for prolonged desiccation. Human activity is associated with these surfaces. The human remains and related archaeology are preserved because a mudflow (Unit 3) plowed into and overrode the land surface upon which the humans had lived, resulting in the deformation and burial of the surface and the preservation of the archaeological material. Provisional radiocarbon dates indicate that Units 2C and 2 accumulated from before ca. 45,000 B.P. until ca. 38,000 B.P. Dates bracketing the Deep Skull give this an age of ca. 45,000 B.P. to ca. 43,000 B.P. Overlying the mudflow, Unit 4, a silty diamicton with a relatively high carbonate and organic content, appears to have formed by a mix of natural colluvial and human transport processes, and is associated with human cultural material. Unpublished radiocarbon dates indicate that this deposit formed from before ca. 19,500 B.P. to ca. 8500 B.P. (uncalibrated).This interpretation of the site and its finds has required detailed reconstruction of the changing palaeogeography within and beyond the cave entrance and the nature and rate of geomorphological processes operating within the region, which have been placed within models for rapid Quaternary environmental change. The results suggest that during the earlier period of human presence in the Great Cave of Niah(earlier than ca. 45,000 B.P. until ca. 38,000 B.P.), the climate was episodically wet with much longer periods of relative dryness. During the later period of human occupancy (ca. 19,500 B.P. to ca. 8500 B.P. [uncalibrated]), the evidence is less secure and a slightly moister climate is suggested.


Asian Perspectives | 2005

Micromorphology of Cave Sediments in the Humid Tropics: Niah Cave, Sarawak

Mark Stephens; James Rose; David Gilbertson; Matthew G. Canti

This is the first detailed study of the micromorphology of archaeologically important cave sediments in the Great Cave of Niah, in the humid tropics of Sarawak, Borneo. Micromorphology is used to describe the sediments and post-depositional alteration, reconstruct the palaeoenvironments, and refine the environmental history of late Pleistocene deposits associated with the human remains (the so-called Deep Skull dated to ca. 43,000-42,000 B.P.). Micromorphology provides details of the shape, roundedness, arrangement, and chemistry of grains, aggregates, precipitates, and sedimentary structures that make up the cave sediments. The dominant processes in the West Mouth of the Great Cave of Niah are guano sedimentation, fluvial and shallow pond deposition interrupted by desiccation, mass movement, and chemical weathering. Also important is post-depositional alteration by bioturbation, mineral translocation and reprecipitation, and diagenesis. Micromorphology also provides evidence for short periods of soil development, burnt surfaces, and deposition of small fragments of bone within the sediment. Together this information indicates the fine details of the environment occupied by humans, the scale and effects of the mass movement processes that deformed the beds in which the human remains are preserved, and the taphonomic processes that reworked and redistributed archaeological material within this part of the cave.


Journal of Human Evolution | 2008

Hovk 1 and the Middle and Upper Paleolithic of Armenia: a preliminary framework

Ron Pinhasi; Boris Gasparian; Keith Wilkinson; Richard M. Bailey; Guy Bar-Oz; A.A. Bruch; C. Chataigner; Dirk L. Hoffmann; R. Hovsepyan; Samvel Nahapetyan; A.W.G. Pike; Danielle C. Schreve; Mark Stephens

The territory of present day Armenia is a geographic contact zone between the Near East and the northern Caucasus. Armenian Middle and Upper Paleolithic records are both few and patchy as a result of the historical paucity of systematic archaeological research in the country. Consequently, it is currently difficult to correlate the Armenian Middle and Upper Paleolithic records with those from other neighboring regions. We present new archaeological and chronometric data (luminescence, U-Th, and 14C) from our ongoing research at Hovk 1 Cave in northeast Armenia. We discuss in particular two activity phases in Hovk 1 Cave for which we have outline chronometric data: (1) an early Middle Paleolithic occupational phase, dated by optically stimulated luminescence (OSL) to 104+/-9.8 ka BP(OSL); and (2) a Paleolithic occupational phase characterized by microlithic flakes dated by AMS 14C to 39,109+/-1,324 calibrated years BP(Hulu). The two phases are separated by a hiatus in hominin occupation corresponding to MIS 4 and an episode in early MIS 3. These chronometric data, taken together with the preliminary paleoenvironmental reconstruction of the Hovk 1 Cave and environment, suggest that these activity phases represent short-lived and seasonal use of the cave presumably by small groups of hunters during episodes of mild climate. Neither tool manufacture nor butchery appears to have taken place within the cave, and consequently, the archaeological record included, for the most part, finished tools and blanks. We address the chronology and techno-typological aspects of Hovk 1 lithics in relation to: (1) the Paleolithic records of Armenia, and (2) the broader interregional context of early Middle Paleolithic hominin occupation and the Middle-Upper Paleolithic transition in the Caucasus.


Developments in Quaternary Science | 2011

Palaeoenvironments of Ancient Humans in Britain: The Application of Oxygen and Carbon Isotopes to the Reconstruction of Pleistocene Environments

Ian Candy; Mark Stephens; Jonathan Hancock; Ruth Waghorne

Abstract Stable oxygen and carbon isotopes in continental carbonates are used routinely as palaeoenvironmental proxies in Quaternary sequences. In the British Quaternary record, this approach has been relatively under-utilised despite the abundance of a wide variety of carbonate types, including soil and groundwater precipitates, tufa, freshwater and terrestrial mollusc shells and lacustrine carbonates. As part of the Ancient Human Occupation of Britain project, the potential of this approach for understanding the climates and environments of early humans in Britain has been investigated. These studies involved two stages: (1) the analysis of modern carbonates to understand how the stable isotope composition of these materials record modernenvironmental conditions; and (2) the application of these modern analogue studies to the investigation of carbonates from a number of British interglacial episodes. The application of this technique is discussed with reference to two archaeologically significant periods, the Cromerian Complex and the Hoxnian. These examples highlight the potential for using this technique to understand temperatures in past interglacials. The chapter concludes by discussing the significance of these studies to understanding the environments of human occupation.


The South Pacific Journal of Natural and Applied Sciences | 2014

Temperature trends in Fiji: a clear signal of climate change

Ravind Kumar; Mark Stephens; Tony Weir

This paper analyses trends in temperature in Fiji, using data from more stations (10) and longer periods (52-78 years) than previous studies. All the stations analysed show a statistically significant trend in both maximum and minimum temperature, with increases ranging from 0.08 to 0.23 o C per decade. More recent temperatures show a higher rate of increase, particularly in maximum temperature (0.18 to 0.69 o C per decade from 1989 to 2008). This clear signal of climate change is consistent with that found in previous studies of temperatures in Fiji and other Pacific Islands. Trends in extreme values show an even stronger signal of climate change than that for mean temperatures. Our preliminary analysis of daily maxima at 6 stations indicates that for 4 of them (Suva, Labasa, Vunisea and Rotuma) there has been a tripling in the number of days per year with temperature >32 o C between 1970 and 2008. The correlations between annual mean maximum (minimum) temperature and year are mostly strong: for about half the stations the correlation coefficient exceeds 60% over 50+ years. Trends do not vary systematically with location of station. At all 7 stations for which both trends are available there is no statistically significant difference between the trends in maximum and minimum temperatures.


Journal of Human Evolution | 2007

The 'human revolution' in lowland tropical Southeast Asia: the antiquity and behavior of anatomically modern humans at Niah Cave (Sarawak, Borneo)

Graeme Barker; Huw Barton; Michael I. Bird; Patrick Daly; Ipoi Datan; Alan P. Dykes; Lucy Farr; David Gilbertson; Barbara Harrisson; Chris Hunt; Thomas Higham; Lisa Kealhofer; John Krigbaum; Helen Lewis; Sue McLaren; Victor Paz; A.W.G. Pike; Phil Piper; Brian Pyatt; Ryan Rabett; Tim Reynolds; J. Rose; Garry Rushworth; Mark Stephens; Chris Stringer; Jill Thompson; Chris S. M. Turney


Journal of Archaeological Science | 2008

Shell-gathering from mangroves and the seasonality of the Southeast Asian Monsoon using high-resolution stable isotopic analysis of the tropical estuarine bivalve (Geloina erosa) from the Great Cave of Niah, Sarawak : methods and reconnaissance of molluscs of early Holocene and modern times

Mark Stephens; David P. Mattey; David Gilbertson; Colin V. Murray-Wallace


Sarawak museum journal | 2002

The Niah cave project: The third (2002) season of fieldwork

Graeme Barker; Huw Barton; Michael I. Bird; Franca Cole; Patrick Daly; David Gilbertson; Chris Hunt; John Krigbaum; Cynthia Lampert; Helen Lewis; Lindsay Lloyd-Smith; Jessica Manser; Sue McLaren; Francesco Menotti; Victor Paz; Phil Piper; Brian Pyatt; Ryan Rabett; Tim Reynolds; Mark Stephens; Jill Thompson; Mark Trickett; Paula Whittaker


Journal of Archaeological Science | 2017

Post-depositional alteration of humid tropical cave sediments: Micromorphological research in the Great Cave of Niah, Sarawak, Borneo

Mark Stephens; J. Rose; Dd Gilbertson


Earth Surface Processes and Landforms | 2005

Modern stable isotopic (δ18O, δ2H, δ13C) variation in terrestrial, fluvial, estuarine and marine waters from north-central Sarawak, Malaysian Borneo

Mark Stephens; James Rose

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Chris Hunt

Liverpool John Moores University

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Sue McLaren

University of Leicester

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Brian Pyatt

Nottingham Trent University

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Fb Pyatt

Nottingham Trent University

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