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South Asia is rich in Lower Paleolithic Acheulian sites. These have been attributed to the Middle Pleistocene on the basis of a small number of dates, with a few older but disputed age estimates. Here, we report new ages from the excavated site of Attirampakkam, where paleomagnetic measurements and direct (26)Al/(10)Be burial dating of stone artifacts now position the earliest Acheulian levels as no younger than 1.07 million years ago (Ma), with a pooled average age of 1.51 ± 0.07 Ma. These results reveal that, during the Early Pleistocene, India was already occupied by hominins fully conversant with an Acheulian technology including handaxes and cleavers among other artifacts. This implies that a spread of bifacial technologies across Asia occurred earlier than previously accepted.

Diatom genera in many large East African lakes change little throughout the Holocene period suggesting relatively stable ecological conditions and some resilience to environmental change. Ecosystem stability is less common in smaller, more sensitive lakes, such as those within volcanic craters, where external impacts can cause abrupt and rapid fluctuations. A 4100-year diatom and cyanobacteria pigment record from Lake Massoko, a volcanic crater lake in southern Tanzania, is used to illustrate important switches in resource ratios following tephra deposition 1190 years ago. It is hypothesized that the tephra reduced the rate of P diffusion from the sediments and increased the Si:P ratio in the lake. A period of acute change in planktonic diatom communities resulted from the tephra impact and lasted c. 110 years. The magnitude of the change shown by the diatoms and their slow recovery from the tephra may be due in part to a coincident fall in lake level caused by a reduction in regional rainfall. The statistical significance of the tephra impact relative to that of catchment and climate change has been tested using variance partitioning and rate-of-change analysis. Multiproxy indicators show an important period of positive water balance 1700 ago and a relatively dry episode persisting between 1000 and 400 years ago. The lake ecosystem is shown to be highly sensitive to both climate change and tephra deposition.

The large collections of fossil hominid remains from Hadar, Ethiopia, derive from the Afar Triangle of the continental East African Rift. The fossils constitute much of the paratype series of Australopithecus afarensis (Johanson, White, and Coppens, 1978*).Citations for starred (*) references appear in Appendix 2, Publications. The primitive morphology exhibited by these hominids is consistent with their chronologic placement between 3.0 and 4.0 m.y. This paper provides the geographic, historic, stratigraphic, paleoenvironmental, and systematic background for Hadar fossil hominids described in this volume.

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