Main East Research Articles

Population dynamics during the Acheulean at ~0.8 Ma in East and Southeast Asia: Considering the influence of two geological cataclysms

There is increasing evidence that confirms the existence of the Acheulean or Acheulean-like technology at sites in Southeast and East Asia, especially for its earliest appearance at ~0.8 Ma, and two competing hypotheses have been proposed to interpret its origins. Regardless of whether this technology is due to Acheulean population movements or to independent invention, however, one clear feature of these earlier sites is the significantly low lithic densities and infrequent numbers of Large Cutting Tools (LCTs) (e.g., for sites in the Bose Basin). Various hypotheses have been proposed to account for these low artefact densities. In this paper, we consider the interplay between cataclysmic events in the environment and population dynamics during the Acheulean in the Bose Basin, which has received little attention with regard to ecology. We focus on two sudden penecontemporaneous geological events at ~0.8 Ma: the Australasian tektite fall and the oldest Toba super-eruption, both of which have been well documented in Southeast Asia and the southern part of South China and have been confirmed as causing severe environmental change (e.g., deforestation). We propose that this destruction of the original habitat created a population bottleneck effect for the toolmakers, who very likely occupied the landscape at approximately the same time as the cataclysms. This study broadens our understanding of the regional character of the Acheulean sites in Southeast and East Asia, and it provides an interesting case study that highlights the potential relationship between Acheulean population dynamics and sudden environmental change.

Global C cycle perturbations recorded in marbles: a record of Neoproterozoic Earth history within the Dalradian succession of the Shetland Islands, Scotland

Abstract: The Shetland Islands in Scotland contain a c . 12 km thick, mostly siliciclastic Neoproterozoic succession that experienced deformation and greenschist- to amphibolite-facies metamorphism during the Ordovician–Silurian Caledonian Orogeny. Correlating these rocks with Neoproterozoic successions elsewhere has remained problematic. However, four marble units punctuate the succession; these are, in stratigraphic order, the Weisdale, Whiteness, Girlsta and Laxfirth Limestones, two of which record hallmark C-isotopic excursions diagnostic of Neoproterozoic time. The Whiteness Limestone is lithologically similar to the 635 Ma Marinoan post-glacial cap carbonate sequence and displays a δ 13 C carbonate profile in which values decline from a range of 0 to +2‰ to a nadir of −5‰ and then rise towards and oscillate around 0‰. The Girlsta Limestone is a 700–900 m thick marble unit with values of −9‰ to −11‰ and is interpreted as recording the late Neoproterozoic Shuram–Wonoka event. These correlations permit linking the Shetland succession to Neoproterozoic sections elsewhere and also show that rift-related rocks in Shetland post-date the Shuram–Wonoka event (post c . 600 Ma–pre c . 550 Ma) thereby supporting the concept of a diachronous phase of extensional tectonism, from c . 700 Ma in east–central Laurentia to near the close of the Proterozoic in northeastern Laurentia, prior to the opening of the Iapetus Ocean.

Earliest Acheulian Industry from Peninsular India

Decouverte d'un assemblage de 152 objets lithiques a Bori (Maharashtra, Inde) representant le plus ancien materiel connu de l'Acheuleen du subcontinent indien