SciCombinator

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Concept: Holocene

188

Hunter-gatherers living in Europe during the transition from the late Pleistocene to the Holocene intensified food acquisition by broadening the range of resources exploited to include marine taxa. However, little is known on the nature of this dietary change in the Mediterranean Basin. A key area to investigate this issue is the archipelago of the Ègadi Islands, most of which were connected to Sicily until the early Holocene. The site of Grotta d'Oriente, on the present-day island of Favignana, was occupied by hunter-gatherers when Postglacial environmental changes were taking place (14,000-7,500 cal BP). Here we present the results of AMS radiocarbon dating, palaeogenetic and isotopic analyses undertaken on skeletal remains of the humans buried at Grotta d'Oriente. Analyses of the mitochondrial hypervariable first region of individual Oriente B, which belongs to the HV-1 haplogroup, suggest for the first time on genetic grounds that humans living in Sicily during the early Holocene could have originated from groups that migrated from the Italian Peninsula around the Last Glacial Maximum. Carbon and nitrogen isotope analyses show that the Upper Palaeolithic and Mesolithic hunter-gatherers of Favignana consumed almost exclusively protein from terrestrial game and that there was only a slight increase in marine food consumption from the late Pleistocene to the early Holocene. This dietary change was similar in scale to that at sites on mainland Sicily and in the rest of the Mediterranean, suggesting that the hunter-gatherers of Grotta d'Oriente did not modify their subsistence strategies specifically to adapt to the progressive isolation of Favignana. The limited development of technologies for intensively exploiting marine resources was probably a consequence both of Mediterranean oligotrophy and of the small effective population size of these increasingly isolated human groups, which made innovation less likely and prevented transmission of fitness-enhancing adaptations.

Concepts: Stone Age, Last Glacial Maximum, Isotope, Holocene, Paleolithic, Mediterranean Sea, Human, Pleistocene

181

Extinction of the woolly mammoth in Beringia has long been subject to research and speculation. Here we use a new geo-referenced database of radiocarbon-dated evidence to show that mammoths were abundant in the open-habitat of Marine Isotope Stage 3 (∼45-30 ka). During the Last Glacial Maximum (∼25-20 ka), northern populations declined while those in interior Siberia increased. Northern mammoths increased after the glacial maximum, but declined at and after the Younger Dryas (∼12.9-11.5 ka). Remaining continental mammoths, now concentrated in the north, disappeared in the early Holocene with development of extensive peatlands, wet tundra, birch shrubland and coniferous forest. Long sympatry in Siberia suggests that humans may be best seen as a synergistic cofactor in that extirpation. The extinction of island populations occurred at ∼4 ka. Mammoth extinction was not due to a single cause, but followed a long trajectory in concert with changes in climate, habitat and human presence.

Concepts: Climate, Extinction, Little Ice Age, Younger Dryas, Woolly mammoth, Mammoth, Pleistocene, Holocene

160

Human modification of natural landscapes has influenced surface processes in many settings on Earth. Quantitative data comparing the distribution and behavior of geologic phenomena before and after human arrival are sparse but urgently required to evaluate possible anthropogenic influences on geologic hazards. We conduct field and imagery-based mapping, statistical analysis, and numerical modeling of rockfall boulders triggered by the fatal 2011 Christchurch earthquakes (n = 285) and newly identified prehistoric (Holocene and Pleistocene) boulders (n = 1049). Prehistoric and modern boulders are lithologically equivalent, derived from the same source cliff, and yield consistent power-law frequency-volume distributions. However, a significant population of modern boulders (n = 26) traveled farther downslope (>150 m) than their most-traveled prehistoric counterparts, causing extensive damage to residential dwellings at the foot of the hillslope. Replication of prehistoric boulder distributions using three-dimensional rigid-body numerical models that incorporate lidar-derived digital topography and realistic boulder trajectories and volumes requires the application of a drag coefficient, attributed to moderate to dense slope vegetation, to account for their spatial distribution. Incorporating a spatially variable native forest into the models successfully predicts prehistoric rockfall distributions. Radiocarbon dating provides evidence for 17th to early 20th century deforestation at the study site during Polynesian and European colonization and after emplacement of prehistoric rockfall. Anthropocene deforestation enabled modern rockfalls to exceed the limits of their prehistoric predecessors, highlighting a shift in the geologic expression of rockfalls due to anthropogenic activity. Reforestation of hillslopes by mature native vegetation could help reduce future rockfall hazard.

Concepts: Distribution, Boulder, Erosion, Human, Geologic time scale, Global warming, Holocene, 20th century

133

The earliest cranial surgery (trepanation) has been attested since the Mesolithic period. The meaning of such a practice remains elusive but it is evident that, even in prehistoric times, humans from this period and from the Neolithic period had already achieved a high degree of mastery of surgical techniques practiced on bones. How such mastery was acquired in prehistoric societies remains an open question. The analysis of an almost complete cow cranium found in the Neolithic site of Champ-Durand (France) (3400-3000 BC) presenting a hole in the right frontal bone reveals that this cranium underwent cranial surgery using the same techniques as those used on human crania. If bone surgery on the cow cranium was performed in order to save the animal, Champ-Durant would provide the earliest evidence of veterinary surgical practice. Alternatively, the evidence of surgery on this cranium can also suggest that Neolithic people practiced on domestic animals in order to perfect the technique before applying it to humans.

Concepts: Skull, Meaning of life, Prehistory, Human, Holocene, Paleolithic, Neolithic, Stone Age

108

The late Quaternary megafauna extinction was a severe global-scale event. Two factors, climate change and modern humans, have received broad support as the primary drivers, but their absolute and relative importance remains controversial. To date, focus has been on the extinction chronology of individual or small groups of species, specific geographical regions or macroscale studies at very coarse geographical and taxonomic resolution, limiting the possibility of adequately testing the proposed hypotheses. We present, to our knowledge, the first global analysis of this extinction based on comprehensive country-level data on the geographical distribution of all large mammal species (more than or equal to 10 kg) that have gone globally or continentally extinct between the beginning of the Last Interglacial at 132,000 years BP and the late Holocene 1000 years BP, testing the relative roles played by glacial-interglacial climate change and humans. We show that the severity of extinction is strongly tied to hominin palaeobiogeography, with at most a weak, Eurasia-specific link to climate change. This first species-level macroscale analysis at relatively high geographical resolution provides strong support for modern humans as the primary driver of the worldwide megafauna losses during the late Quaternary.

Concepts: Holocene extinction, Species, Extinction, Mammal, Pleistocene, Human, Holocene, Megafauna

86

The United Nations Framework Convention on Climate Change Paris Agreement of December 2015 aims to maintain the global average warming well below 2°C above the preindustrial level. In the Mediterranean basin, recent pollen-based reconstructions of climate and ecosystem variability over the past 10,000 years provide insights regarding the implications of warming thresholds for biodiversity and land-use potential. We compare scenarios of climate-driven future change in land ecosystems with reconstructed ecosystem dynamics during the past 10,000 years. Only a 1.5°C warming scenario permits ecosystems to remain within the Holocene variability. At or above 2°C of warming, climatic change will generate Mediterranean land ecosystem changes that are unmatched in the Holocene, a period characterized by recurring precipitation deficits rather than temperature anomalies.

Concepts: Sustainability, Mediterranean climate, Weather, Holocene, Lebanon, Climate change, Ecosystem, Climate

84

Time is divided by geologists according to marked shifts in Earth’s state. Recent global environmental changes suggest that Earth may have entered a new human-dominated geological epoch, the Anthropocene. Here we review the historical genesis of the idea and assess anthropogenic signatures in the geological record against the formal requirements for the recognition of a new epoch. The evidence suggests that of the various proposed dates two do appear to conform to the criteria to mark the beginning of the Anthropocene: 1610 and 1964. The formal establishment of an Anthropocene Epoch would mark a fundamental change in the relationship between humans and the Earth system.

Concepts: Modular arithmetic, Geography, Aristotle, Paleontology, Holocene, Earth, Geology, Geologic time scale

71

Surface temperature reconstructions of the past 1500 years suggest that recent warming is unprecedented in that time. Here we provide a broader perspective by reconstructing regional and global temperature anomalies for the past 11,300 years from 73 globally distributed records. Early Holocene (10,000 to 5000 years ago) warmth is followed by ~0.7°C cooling through the middle to late Holocene (<5000 years ago), culminating in the coolest temperatures of the Holocene during the Little Ice Age, about 200 years ago. This cooling is largely associated with ~2°C change in the North Atlantic. Current global temperatures of the past decade have not yet exceeded peak interglacial values but are warmer than during ~75% of the Holocene temperature history. Intergovernmental Panel on Climate Change model projections for 2100 exceed the full distribution of Holocene temperature under all plausible greenhouse gas emission scenarios.

Concepts: Greenhouse gas, Temperature, Solar variation, Interglacial, Climate, Global warming, Climate change, Holocene

65

The nature of inter-group relations among prehistoric hunter-gatherers remains disputed, with arguments in favour and against the existence of warfare before the development of sedentary societies. Here we report on a case of inter-group violence towards a group of hunter-gatherers from Nataruk, west of Lake Turkana, which during the late Pleistocene/early Holocene period extended about 30 km beyond its present-day shore. Ten of the twelve articulated skeletons found at Nataruk show evidence of having died violently at the edge of a lagoon, into which some of the bodies fell. The remains from Nataruk are unique, preserved by the particular conditions of the lagoon with no evidence of deliberate burial. They offer a rare glimpse into the life and death of past foraging people, and evidence that warfare was part of the repertoire of inter-group relations among prehistoric hunter-gatherers.

Concepts: Lake Turkana, Violence against women, Domestic violence, Kenya, War, Life, Holocene, Violence

58

Shamanic belief systems represent the first form of religious practice visible within the global archaeological record. Here we report on the earliest known evidence of shamanic costume: modified red deer crania headdresses from the Early Holocene site of Star Carr (c. 11 kya). More than 90% of the examples from prehistoric Europe come from this one site, establishing it as a place of outstanding shamanistic/cosmological significance. Our work, involving a programme of experimental replication, analysis of macroscopic traces, organic residue analysis and 3D image acquisition, metrology and visualisation, represents the first attempt to understand the manufacturing processes used to create these artefacts. The results produced were unexpected-rather than being carefully crafted objects, elements of their production can only be described as expedient.

Concepts: Manufacturing, Archaeological site, Faith, Holocene, Mesolithic, Archaeology, Religion, Prehistory