The first peoples of the Atacama Desert lived among the trees: A 11,600- to 11,200-year-old grove and congregation site.

In deserts, water has been singled out as the most important factor for choosing where to settle, but trees were likely an important part of the landscape for hunter-gatherers beyond merely constituting an economic resource. Yet, this critical aspect has not been considered archaeologically. Here, we present the results of mapping and radiocarbon dating of a truly unique archaeological record.

Description and taxonomic assessment of fossil Cercopithecidae from the Pliocene Galili Formation (Ethiopia).

The Mount Galili Formation in the Afar region, Ethiopia, samples a critical time in hominin evolution, 4.4 to 3.8 Ma, documenting the last appearance of Ardipithecus and the origin of Australopithecus.

Rapid and precise measurement of carbonate clumped isotopes using laser spectroscopy.

Carbonate clumped isotope abundance is an important paleothermometer, but measurement is difficult, slow, and subject to cardinal mass () interferences using isotope ratio mass spectrometry (IRMS). Here, we describe an optical spectroscopic measurement of carbonate clumped isotopes. We have adapted a tunable infrared laser differential absorption spectrometer (TILDAS) system to measure the abundances of four CO isotopologues used for clumped isotope thermometry.

High- and low-latitude forcings drive Atacama Desert rainfall variations over the past 16,000 years.

Late Quaternary precipitation dynamics in the central Andes have been linked to both high- and low-latitude atmospheric teleconnections. We use present-day relationships between fecal pellet diameters from ashy chinchilla rats () and mean annual rainfall to reconstruct the timing and magnitude of pluvials (wet episodes) spanning the past 16,000 years in the Atacama Desert based on 81 C-dated paleomiddens. A transient climate simulation shows that pluvials identified at 15.

Fossil Cercopithecidae from the Early Pliocene Sagantole Formation at Gona, Ethiopia.

The Early Pliocene Sagantole Fm. in the Gona Project area, Afar State, Ethiopia, is noted for discoveries of the early hominin Ardipithecus ramidus. A large series of fossil cercopithecid primates dated to between 4.

Co-occurrence of Acheulian and Oldowan artifacts with cranial fossils from Gona, Afar, Ethiopia.

Although stone tools generally co-occur with early members of the genus , they are rarely found in direct association with hominins. We report that both Acheulian and Oldowan artifacts and crania were found in close association at 1.26 million years (Ma) ago at Busidima North (BSN12), and ca.

Rapid and Precise Analysis of Carbon Dioxide Clumped Isotopic Composition by Tunable Infrared Laser Differential Spectroscopy.

The high precision measurement of doubly substituted ("clumped") isotopologues in CO is a topic of significant interest in isotope geochemistry. Here we describe the performance of a new isotope ratio laser spectrometer using tunable infrared laser differential absorption spectroscopy (TILDAS). The TILDAS instrument has two continuous-wave lasers to simultaneously measure the four isotopologues involved in the CO + COO ⇆ CO + COO exchange reaction.

Ardipithecus ramidus postcrania from the Gona Project area, Afar Regional State, Ethiopia.

Functional analyses of the 4.4 Ma hominin Ardipithecus ramidus postcrania revealed a previously unknown and unpredicted locomotor pattern combining arboreal clambering and a form of terrestrial bipedality. To date, all of the fossil evidence of Ar.

North-south dipole in winter hydroclimate in the western United States during the last deglaciation.

During the termination of the last glacial period the western U.S. experienced exceptionally wet conditions, driven by changes in location and strength of the mid-latitude winter storm track.

Significant Impacts of Increasing Aridity on the Arid Soil Microbiome.

Global deserts occupy one-third of the Earth's surface and contribute significantly to organic carbon storage, a process at risk in dryland ecosystems that are highly vulnerable to climate-driven ecosystem degradation. The forces controlling desert ecosystem degradation rates are poorly understood, particularly with respect to the relevance of the arid-soil microbiome. Here we document correlations between increasing aridity and soil bacterial and archaeal microbiome composition along arid to hyperarid transects traversing the Atacama Desert, Chile.

Late Miocene hominin teeth from the Gona Paleoanthropological Research Project area, Afar, Ethiopia.

Since 2000, significant collections of Latest Miocene hominin fossils have been recovered from Chad, Kenya, and Ethiopia. These fossils have provided a better understanding of earliest hominin biology and context. Here, we describe five hominin teeth from two periods (ca.

A forager-herder trade-off, from broad-spectrum hunting to sheep management at Aşıklı Höyük, Turkey.

Aşıklı Höyük is the earliest known preceramic Neolithic mound site in Central Anatolia. The oldest Levels, 4 and 5, spanning 8,200 to approximately 9,000 cal B.C.

Bomb-curve radiocarbon measurement of recent biologic tissues and applications to wildlife forensics and stable isotope (paleo)ecology.

Above-ground thermonuclear weapons testing from 1952 through 1962 nearly doubled the concentration of radiocarbon ((14)C) in the atmosphere. As a result, organic material formed during or after this period may be radiocarbon-dated using the abrupt rise and steady fall of the atmospheric (14)C concentration known as the bomb-curve. We test the accuracy of accelerator mass spectrometry radiocarbon dating of 29 herbivore and plant tissues collected on known dates between 1905 and 2008 in East Africa.

Life at the hyperarid margin: novel bacterial diversity in arid soils of the Atacama Desert, Chile.

Nearly half the earth's surface is occupied by dryland ecosystems, regions susceptible to reduced states of biological productivity caused by climate fluctuations. Of these regions, arid zones located at the interface between vegetated semiarid regions and biologically unproductive hyperarid zones are considered most vulnerable. The objective of this study was to conduct a deep diversity analysis of bacterial communities in unvegetated arid soils of the Atacama Desert, to characterize community structure and infer the functional potential of these communities based on observed phylogenetic associations.

Woody cover and hominin environments in the past 6 million years.

The role of African savannahs in the evolution of early hominins has been debated for nearly a century. Resolution of this issue has been hindered by difficulty in quantifying the fraction of woody cover in the fossil record. Here we show that the fraction of woody cover in tropical ecosystems can be quantified using stable carbon isotopes in soils.

Comment on the paleoenvironment of Ardipithecus ramidus.

White and colleagues (Research Articles, 2 October 2009, pp. 65-67 and www.sciencemag.

A female Homo erectus pelvis from Gona, Ethiopia.

Analyses of the KNM-WT 15000 Homo erectus juvenile male partial skeleton from Kenya concluded that this species had a tall thin body shape due to specialized locomotor and climatic adaptations. Moreover, it was concluded that H. erectus pelves were obstetrically restricted to birthing a small-brained altricial neonate.

Bacterial community structure in the hyperarid core of the Atacama Desert, Chile.

Soils from the hyperarid Atacama Desert of northern Chile were sampled along an east-west elevational transect (23.75 to 24.70 degrees S) through the driest sector to compare the relative structure of bacterial communities.

Raw material selectivity of the earliest stone toolmakers at Gona, Afar, Ethiopia.

Published evidence of Oldowan stone exploitation generally supports the conclusion that patterns of raw material use were determined by local availability. This is contradicted by the results of systematic studies of raw material availability and use among the earliest known archaeological sites from Gona, Afar, Ethiopia. Artifact assemblages from six Pliocene archaeological sites were compared with six random cobble samples taken from associated conglomerates that record pene-contemporaneous raw material availability.

Early Pliocene hominids from Gona, Ethiopia.

Comparative biomolecular studies suggest that the last common ancestor of humans and chimpanzees, our closest living relatives, lived during the Late Miocene-Early Pliocene. Fossil evidence of Late Miocene-Early Pliocene hominid evolution is rare and limited to a few sites in Ethiopia, Kenya and Chad. Here we report new Early Pliocene hominid discoveries and their palaeoenvironmental context from the fossiliferous deposits of As Duma, Gona Western Margin (GWM), Afar, Ethiopia.

Sourcing sediment using multiple tracers in the catchment of Lake Argyle, Northwestern Australia.

Control of sedimentation in large reservoirs requires soil conservation at the catchment scale. In large, heterogeneous catchments, soil conservation planning needs to be based on sound information, and set within the framework of a sediment budget to ensure that all of the potentially significant sources and sinks are considered. The major sources of sediment reaching the reservoir, Lake Argyle, in tropical northwestern Australia, have been determined by combining measured sediment fluxes in rivers with spatial tracer-based estimates of proportional contributions from tributaries of the main stream entering the lake, the Ord River.