Michael C. Meyer

Fire As an Engineering Tool of Early Modern Humans

Friendly Fire Hints of the use of more advanced materials by humans, including symbolic marking and jewelry, appear about 75,000 years ago or so in Africa. Brown et al. (p. 859; see the Perspective by Webb and Domanski) now show that these early modern humans were also experimenting with the use of fire for improved processing of materials. Replication experiments and analysis of artifacts suggest that humans in South Africa at this time, and perhaps earlier, systematically heated stone materials, including silcrete to improve its flaking properties in making tools. Early modern humans used fire to improve the fracturing of silcrete in making tools in South Africa 72,000 years ago. The controlled use of fire was a breakthrough adaptation in human evolution. It first provided heat and light and later allowed the physical properties of materials to be manipulated for the production of ceramics and metals. The analysis of tools at multiple sites shows that the source stone materials were systematically manipulated with fire to improve their flaking properties. Heat treatment predominates among silcrete tools at ~72 thousand years ago (ka) and appears as early as 164 ka at Pinnacle Point, on the south coast of South Africa. Heat treatment demands a sophisticated knowledge of fire and an elevated cognitive ability and appears at roughly the same time as widespread evidence for symbolic behavior.

New excavations at the site of Contrebandiers Cave, Morocco

PaleoAnthropology 2012: 145−201.

Permanent human occupation of the central Tibetan Plateau in the early Holocene

The peopling of Tibet The date of the first permanent human occupation of the high Tibetan Plateau has been estimated at about 3600 years ago, when agriculture became established. Meyer et al. used several dating techniques to analyze sediments at a high-altitude site (4270 m) where human handprints and footprints have been found. Their analysis indicates occupation of the plateau 7400 years ago and possibly earlier. These dates are consistent with the genetic history of Tibetans and suggest that a permanent preagricultural peopling of the plateau was enabled by the wetter regional climate at that time. Science, this issue p. 64 The dating of the Chusang site supports the presence, more than 7000 years ago, of a preagricultural community high in Tibet. Current models of the peopling of the higher-elevation zones of the Tibetan Plateau postulate that permanent occupation could only have been facilitated by an agricultural lifeway at ~3.6 thousand calibrated carbon-14 years before present. Here we report a reanalysis of the chronology of the Chusang site, located on the central Tibetan Plateau at an elevation of ~4270 meters above sea level. The minimum age of the site is fixed at ~7.4 thousand years (thorium-230/uranium dating), with a maximum age between ~8.20 and 12.67 thousand calibrated carbon-14 years before present (carbon-14 assays). Travel cost modeling and archaeological data suggest that the site was part of an annual, permanent, preagricultural occupation of the central plateau. These findings challenge current models of the occupation of the Tibetan Plateau.

Speleothems and mountain uplift

Ancient speleothems were recovered from caves that today are situated in a high-alpine cirque landscape at 2500 m altitude at the northern rim of the European Alps. U-Pb ages date speleothem deposition to the early Quaternary (between 2.16 and 2.12 Ma and ca. 2.00 Ma), i.e., well before the onset of major alpine and Northern Hemisphere glaciations. Using a stable isotope–based modeling approach, we quantitatively estimate the paleoelevation of both the caves and their former catchment area, which in turn allows us to calculate rates of rock and surface uplift (and hence erosion) since 2 Ma. We show that for the frontal part of the Alps, rates of rock uplift and erosion were ∼0.75 and ∼0.5 mm/yr, respectively, and further suggest that isostatic uplift of mountain peaks of as much as ∼500 m in response to enhanced glacial erosion occurred during the Quaternary. This study highlights the potential of U-Pb-dated speleothems for reconstructing paleoaltimetry, particularly in calcareous mountain ranges, where a standard thermochronologic assessment of exhumation and erosion is generally not feasible.

Evidence for steady fault-accommodated strain in the High Himalaya: progressive fault rotation of the southern Tibet detachment system in NW Bhutan

Abstract We present fault analyses from the exhumed middle crustal slab of the High Himalaya in eastern Lunana in NW Bhutan. Fault planes from within two-mica, tourma-line-bearing leucogranites, leucogranitic rocks and migmatites indicate a complex brittle fault pattern with two distinct fault groups. A first group of faults (D1) characterized by chlorite, quartz and tourmaline slickenfibres is mainly defined by steeply SSE-dipping oblique-slip normal faults, and by shallowly NNW-dipping normal faults. A second, younger group of faults (D2) characterized by cataclasis products comprises strike-slip faults displaying conjugate patterns and E- and W-dipping conjugate normal faults, all which indicate E-W extension. Cross-cutting relationships amongst the D1 fault group demonstrate that progressively steeper members of the fault group become younger within the NNW-dipping faults and become older within the SSE-dipping faults. These are all post-dated by the D2 fault group. The D1 fault group indicates that the slab experienced ongoing NNW-SSE extension (i.e. flow) via brittle fault accommodation, contemporaneous with fault rotation. This may reflect rotation of the entire upper orogen due to movement over deeply located major ramp structures formed by out-of-sequence thrusting (Kakhtang Thrust) within the High Himalayan Slab of the Bhutan Himalaya.

The evolutionary history of dogs in the Americas

Lineage losses for mans best friend Dogs have been present in North America for at least 9000 years. To better understand how present-day breeds and populations reflect their introduction to the New World, Ní Leathlobhair et al. sequenced the mitochondrial and nuclear genomes of ancient dogs (see the Perspective by Goodman and Karlsson). The earliest New World dogs were not domesticated from North American wolves but likely originated from a Siberian ancestor. Furthermore, these lineages date back to a common ancestor that coincides with the first human migrations across Beringia. This lineage appears to have been mostly replaced by dogs introduced by Europeans, with the primary extant lineage remaining as a canine transmissible venereal tumor. Science, this issue p. 81; see also p. 27 Ancient North American dogs survive primarily as a canine transmissible venereal tumor. Dogs were present in the Americas before the arrival of European colonists, but the origin and fate of these precontact dogs are largely unknown. We sequenced 71 mitochondrial and 7 nuclear genomes from ancient North American and Siberian dogs from time frames spanning ~9000 years. Our analysis indicates that American dogs were not derived from North American wolves. Instead, American dogs form a monophyletic lineage that likely originated in Siberia and dispersed into the Americas alongside people. After the arrival of Europeans, native American dogs almost completely disappeared, leaving a minimal genetic legacy in modern dog populations. The closest detectable extant lineage to precontact American dogs is the canine transmissible venereal tumor, a contagious cancer clone derived from an individual dog that lived up to 8000 years ago.

Post-last glacial maximum settlement of the West Angelas region in the inland Hamersley Plateau, Western Australia

Abstract An excavation and survey program at West Angelas, in the Pilbara region of Western Australia, shows that the poorly watered interior area of the Hamersley Plateau was first occupied soon after the conclusion of the Last Glacial Maximum, and that significant use of this area probably only occurred during the mid to late Holocene. Although current archaeological research shows that Aboriginal groups have occupied areas of the Hamersley Plateau for more than 40,000 years, the permanent and prolonged use of the more marginal or ecologically suboptimal foraging environments of the interior plateau is a comparatively recent development in the region’s long archaeological record.

Identifying extreme pluvials in the last millennia using optical dating of single grains of quartz from shorelines on Australia's largest lake

The filling of Kati Thanda-Lake Eyre (KT-LE), Australia’s ‘inland sea’ has captured scientific and cultural interest for over a century and a half. However, despite the presence of multiple shorelines around the modern playa at or near the modern maximum lake-filling levels, no quantitative estimates of major late-Holocene filling events have ever been documented. We develop a preliminary chronological data set using single-grain optically stimulated luminescence (OSL) on lake shoreline samples in order to determine the timing of large lake-filling events (equivalent to 1974 Common Era (CE) as Australia’s wettest year on record) for KT-LE, Australia’s largest lake basin. Despite quartz grains with very low natural dose luminescence (Ln) signal, we derive palaeodoses from geologically recent deposits (decades to centuries) using standard rejection criteria and highlight no signs of partial bleaching but occasional bioturbation in modern deposits. Major modern filling episodes, such as the1974 and 1949/1950 filling events, are successfully captured in the geochronological record, as are two major lake-filling episodes in 1854 ± 21 CE years and 1598–1654 CE. Two additional periods of potential lake-filling events have been identified at 1.2 ± 0.09 and 1.9 ± 0.14 ka, but stratigraphic control on these events is less robust. These chronostratigraphic records, while discontinuous, provide important hydrological evidence for extreme pluvial events akin to 1974 or 1949/1950, and the approach holds promise for identifying climate extremes and landscape response over the late Holocene.

Response to Comment on “Permanent human occupation of the central Tibetan Plateau in the early Holocene”

Zhang et al. contest that Chusang was part of an annual mobility round that “more likely” included seasonal use of high-elevation environments than permanent use. We show that their probabilistic statement hinges on indefensible claims about hunter-gatherer mobility. In the context of quantitative data from hunter-gatherer ethnography, our travel model shows that seasonal-use models are highly unlikely to explain Chusang.