Besiedlung Amerikas: solutréische Hypothese, Beringia, oder Südpazifik?

Und ein neuer Datierungsversuch eisfreier Korridore für Beringia, dem Zuweg für die Besiedlung des amerikanischen Festlandes (hier anhand genetischer Untersuchungen zum Bison)

Heintzmann et. al., Bison phylogeography constrains dispersal and viability of the Ice Free Corridor in western Canada
http://www.pnas.org/content/early/2016/06/01/1601077113.full.pdf

Als Konsequenz wird eine (zweite), postglaziale Besiedlungswelle mit erneuter Öffnung des Korridors ab ca. 13.000 BP angenommen.

"Consequences of the Postglacial Corridor Chronology for North American Human Prehistory. The expansion of bison into the corridor region provides proxy evidence for when this route was viable for human populations and, in doing so, allows further refinement of New World human settlement scenarios. Human genetic and archaeological evidence indicate that eastern Beringia and parts of the Americas well south of the ice sheets were populated by 14,000 cal y BP, suggesting that migration out of Beringia probably began more than 15,000 cal y BP ago (15, 34–36). Our chronology for the opening of the postglacial corridor indicates that a fully habitable corridor connected Beringia and interior North America by ∼13,000 cal y BP. This timing precludes the postglacial corridor as a southward route for initial human dispersal into the Americas, the corollary being that the first indigenous peoples leaving Beringia probably took a coastal route or potentially moved through western North America before glacial coalescence (37, 38).
We find that a bison belonging to the northern clade (2a) reached the Edmonton area by 13,000 cal y BP. It is therefore possible that established northern human populations also reached the central corridor by this time. Evidence from the archaeological record supports this hypothesis. For example, Alaskan archaeological sites including Swan Point, Mead, Broken Mammoth, Tuluaq, and Dry Creek, which were occupied from ∼14,000 to 11,500 cal y BP, fea- ture a variety of projectile technologies, sometimes associated with microblade industries (39). Similar microblade technologies are present at Vermilion Lakes (Banff National Park) and Charlie Lake Cave by ∼11,500 cal y BP (28, 40, 41). In addition, human genetic data from Upward Sun River, Alaska, show founding New World mitochondrial haplotypes B2 and C1b in Alaska at ∼11,500 cal y BP. Small, isolated groups of people may therefore have continued to disperse from Beringia to interior North America well after the corridor region opened (14, 16, 41, 42)."
 
Und ergänzend die Besiedlungsmodelle:

Amick: Evolving views on the Pleistocene colonization of North America

http://s3.amazonaws.com/academia.ed...=Evolving_views_on_the_Pleistocene_coloni.pdf

Wobei zum genetischen Puzzle der postglazialen Besiedlung über Beringia die Pre-Clovis-Besiedlung im Süden passen muss:

Halligan: Pre-Clovis occupation 14,550 years ago at the Page-Ladson site, Florida, and the peopling of the Americas
http://advances.sciencemag.org/content/advances/2/5/e1600375.full.pdf


Und ganz aktuell Skoglund/Reich: A genomic view of the peopling of the Americas
http://www.biorxiv.org/content/biorxiv/early/2016/06/15/058966.full.pdf

"Introduction
The peopling of the Americas represented the culmination of a Late Pleistocene expansion of anatomically modern humans out of Africa. Archaeological evidence indicates that groups subsisting on hunting lived in extreme northeast Siberia (71°N) by at least 28,000 years ago [1]. Human groups adapted to the mammoth steppe habitat were thus poised to enter Beringia—the landmass between Alaska and Eurasia that is now submerged—by this time [2,3]. The path from Beringia to the more temperate parts of the American continents, however, was blocked by the merged Laurentide and Cordilleran ice sheets that covered northern North America until the end of the Last Glacial Maximum. The ice retreated from parts of the Pacific coast ~16,000 years ago, raising the possibility of a coastal migration after this time, and within a few thousand years a habitable corridor through the center of the continent opened between the two ice sheets [4]. The first unambiguous evidence of modern humans in the Americas dates to between 14,000 and 15,000 years ago [5-8], and was likely the consequence of migration from Beringia."
 
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Und weitere Annäherung an die Besiedlungshistorie, diesmal über erste menschliche Nutzung von Feuer auf den California Channel Islands:


"Recent studies have suggested that the first arrival of humans in the Americas during the end of the last Ice Age is associated with marked anthropogenic influences on landscape; in particular, with the use of fire which, would have given even small populations the ability to have broad impacts on the landscape. Understanding the impact of these early people is complicated by the dramatic changes in climate occurring with the shift from glacial to interglacial conditions. Despite these difficulties, we here attempt to test the extent of anthropogenic influence using the California Channel Islands as a smaller, landscape-scale test bed. These islands are famous for the discovery of the ‘Arlington Springs Man’, which are some of the earliest human remains in the Americas. A unifying sedimentary charcoal record is presented from Arlington Canyon, Santa Rosa Island, based on over 20 detailed sedimentary sections from eight key localities. Radiocarbon dating was based on thin, fragile, long fragments of charcoal in order to avoid the ‘inbuilt’ age problem. Radiocarbon dating of 49 such fragments has allowed inferences regarding the fire and landscape history of the Canyon ca 19–11 ka BP. A significant period of charcoal deposition is identified approximately 14–12.5 ka BP and bears remarkable closeness to an estimated age range of the first human arrival on the islands."

Was wiederum heißen würde, dass der Mensch dem Bison bei der Beringia-Öffnung 1000 Jahre "vorauslief":yes:
Hardiman et. al.: Fire history on the California Channel Islands spanning human arrival in the Americas
https://www.researchgate.net/profil...e_Americas/links/5743ec0508ae298602f0f774.pdf
 
Hier eine Zusammenstellung der nachgewiesenen frühesten südamerikanischen Besiedlungen, die pre-Solutreen, aber nach Öffnung des Eisschildes Beringia datieren.

Würde dieses Zeitfenster relevant sein, wäre die kontinentale Besiedlung, zB nach der Küstenlinien-Hypothese, binnen weniger Jahrtausende erfolgt.

"The Arroyo Seco 2 site contains a rich archaeological record, exceptional for South Amer- ica, to explain the expansion of Homo sapiens into the Americas and their interaction with extinct Pleistocene mammals. The following paper provides a detailed overview of material remains found in the earliest cultural episodes at this multi-component site, dated between ca. 12,170 14 C yrs B.P. (ca. 14,064 cal yrs B.P.) and 11,180 14 C yrs B.P. (ca. 13,068 cal yrs B.P.). Evidence of early occupations includes the presence of lithic tools, a concentration of Pleistocene species remains, human-induced fractured animal bones, and a selection of skeletal parts of extinct fauna. The occurrence of hunter-gatherersin the Southern Cone at ca. 14,000 cal yrs B.P. is added to the growing list of American sites that indicate a human occupation earlier than the Clovis dispersal episode, but posterior to the onset of the deglaciation of the Last Glacial Maximum (LGM) in the North America."
PLOS ONE: The Arrival of Homo sapiens into the Southern Cone at 14,000 Years Ago
 
Hier im Thema wurde mehrfach - spekulativ mit dem Erreichen von Amerika - die austronesische Expansion angesprochen.

Das ist derzeit nicht der Stand der Forschung, siehe verlinkte Publikationen.
Allerdings gibt es kein eigenes Thema zur austronesischen Expansion. Deswegen erfolgt hier die Verlinkung zum neusten Aufsatz in der nature.

Dieser weist die "slow-boat"-Hypothese für die Besiedlung Polynesiens zurück, und analysiert zT direkt Besiedlungswellen von Ostasien aus, mit nachfolgenden Überschichtungen durch die austronesische Expansion.
https://www.sciencedaily.com/releases/2016/10/161003130908.htm

Artikel:
"Abstract:
The appearance of people associated with the Lapita culture in the South Pacific around 3,000 years ago1 marked the beginning of the last major human dispersal to unpopulated lands. However, the relationship of these pioneers to the long-established Papuan people of the New Guinea region is unclear. Here we present genome-wide ancient DNA data from three individuals from Vanuatu (about 3,100–2,700 years before present) and one from Tonga (about 2,700–2,300 years before present), and analyse them with data from 778 present-day East Asians and Oceanians. Today, indigenous people of the South Pacific harbour a mixture of ancestry from Papuans and a population of East Asian origin that no longer exists in unmixed form, but is a match to the ancient individuals. Most analyses have interpreted the minimum of twenty-five per cent Papuan ancestry in the region today as evidence that the first humans to reach Remote Oceania, including Polynesia, were derived from population mixtures near New Guinea, before their further expansion into Remote Oceania2, 3, 4, 5. However, our finding that the ancient individuals had little to no Papuan ancestry implies that later human population movements spread Papuan ancestry through the South Pacific after the first peopling of the islands."
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature19844.html
 
Was ich in diesem Zusammenhang darstellen wollte, ist, dass sich seitdem niemand ernsthaft mit der NW-Route von Westsibirien nach Beringia befasst hat, obwohl die mindestens genauso wahrscheinlich und möglich gewesen wäre wie die über den N-Atlantik.

Da stehen dann aber noch einige Lesestunden aus. Hier ein paar Tipps:

Zur Beringia- und Beringia-standstill-Hypothese findet nun ein Kongress statt:
https://aaas.confex.com/aaas/2017/webprogram/Session15339.html

Big-Data kombiniert mit Linguistik, wir hatten das in einem anderen Thema der vergleichenden Sprachforschung, scheint auch wieder eine Rolle zu spielen, neben den Humangenetikern und Archäologen.
https://phys.org/news/2017-02-linguist-big-migration-americas.html
Linguist's 'big data' research supports waves of migration into the Americas

Vielleicht bringt er Lac/Luc neue Erleuchtung nach dem Lesen von Fester.:D
 
Vielleicht sollten wir 'Stand der Wissenschaft' und 'öffentlich bekannt' unterscheiden. Dann könnte man eine konsistente Wortwahl fordern. In Zeiten, da von Lügenpresse die Rede ist, ist so etwas ja geradezu eine Bestätigung der Idioten. Da muss man mal beginnen, ein Bewusstsein bei den Informationsvermittlern zu schaffen.

In diesem Fall kann man zudem, zumindest nach meiner Empfindung, von bewusster Lüge ausgehen. Das andere, die mangelnde Recherche wäre noch beunruhigender.
 
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Ich würde das nicht so hoch hängen, nicht in diese Liga.

Hier geht es erstmal um dreiste Werbung, die Sendung zu pushen.
Wobei ich einiges nicht nachvollziehen kann. Wieso wird die leicht verfügbare Information über die Sachlage - ohne Zweifel nicht minder "spannend" - nicht vermittelt? Wird das ohne Übertreibung quotenseitig als suboptimal angesehen? Wer entscheidet das?

Ist hier aber off-topic.
 
Funde in Brasilien 30000 B.C.

Hallo


Der entsprechende frz. Archäologe hat aber sehr sauber methodisch gearbeitet. Was ich so mitbekommen habe, ist seine Datierung von 25000-30000 durchaus plausibel und schwer zu erschüttern. Einzig, man hat in dem Areal bisher keine Knochenfunde, respektive Zähne gefunden. Außerdem war das Klima vor 30000 Jahren dort angenehmer mit zahlreicher Flaora uind Fauna, also für Menschen sehr gut geigent, anders als heute, wo das Gebiet eine "Buschsteppe" ist, wenig Vegetatation und wenig Wasser.


mfg
schwedenmann
 
Dazu ganz aktuell nun Schädelvermessungen, deren Ergebnisse und Rückschlüsse offenbar zum (derzeit bekannten) populationsgenetischen Forschungsstand passen.

Evolutionary population history of early Paleoamerican cranial morphology | Science Advances

Abstract:
The nature and timing of the peopling of the Americas is a subject of intense debate. In particular, it is unclear whether high levels of between-group craniometric diversity in South America result from multiple migra- tions or from local diversification processes. Previous attempts to explain this diversity have largely focused on testing alternative dispersal or gene flow models, reaching conflicting or inconclusive results. Here, a novel analytical framework is applied to three-dimensional geometric morphometric data to partition the effects of population divergence from geographically mediated gene flow to understand the ancestry of the early South Americans in the context of global human history. The results show that Paleoamericans share a last common ancestor with contemporary Native American groups outside, rather than inside, the Americas. Therefore, and in accordance with some recent genomic studies, craniometric data suggest that the New World was populated by multiple waves of dispersion from northeast Asia throughout the late Pleistocene and early Holocene

Zu Brasilien:
New Data on a Pleistocene Archaeological Sequence in South America: Toca do Sítio do Meio, Piauí, Brazil
http://www.tandfonline.com/doi/abs/10.1080/20555563.2016.1237828?journalCode=ypal20
 
Eine weitere aktuelle Studie aus der PNAS.

Interessant ist der Ansatz der genetischen Selektion, hier speziell des FADS-Gens. Dieses bringt man in Verbindung mit einer Anpassung an arktische Verhältnisse. Da nun diese Selektion über beide Kontinente nachgewiesen wird, würde das nach meinem Verständnis für das Erreichen der "Neuen Welt" via Beringia bzw. B.-standstill sprechen.


Abstract:
When humans moved from Asia toward the Americas over 18,000 y ago and eventually peopled the New World they encountered a new environment with extreme climate conditions and distinct dietary resources. These environmental and dietary pressures may have led to instances of genetic adaptation with the potential to influence the phenotypic variation in extant Native American populations. An example of such an event is the evolution of the fatty acid desaturases (FADS) genes, which have been claimed to harbor signals of positive selection in Inuit populations due to adaptation to the cold Greenland Arctic climate and to a protein-rich diet. Because there was evidence of intercontinental variation in this genetic region, with indications of positive selection for its variants, we decided to compare the Inuit findings with other Native American data. Here, we use several lines of evidence to show that the signal of FADS-positive selection is not restricted to the Arctic but instead is broadly observed throughout the Americas. The shared signature of selection among populations living in such a diverse range of environments is likely due to a single and strong instance of local adaptation that took place in the common ancestral population before their entrance into the New World. These first Americans peopled the whole continent and spread this adaptive variant across a diverse set of environments.

Genetic signature of natural selection in first Americans
 
Da hier mehrfach die Clovis-Materialkultur angesprochen wurde, der Hinweis auf eine neue Publikation (schon einen Monat alt), die das intensiv (auch post-Clovis) für Nordamerika anhand von neuen Messverfahren systematisch untersucht hat, und dabei auch Aussagen zu Interaktionen zwischen den Gruppen aufgrund regionaler Zusammenhänge der Materialkultur oder der "Techniken" trifft:


Tracing social interactions in Pleistocene North America via 3D model analysis of stone tool asymmetry
Tracing social interactions in Pleistocene North America via 3D model analysis of stone tool asymmetry


Abstract

Stone tools, often the sole remnant of prehistoric hunter-gatherer behavior, are frequently used as evidence of ancient human mobility, resource use, and environmental adaptation. In North America, studies of morphological variation in projectile points have provided important insights into migration and interactions of human groups as early as 12–13 kya. Using new approaches to 3D imaging and morphometric analysis, we here quantify bifacial asymmetry among early North American projectile point styles to better understand changes in knapping technique and cultural transmission. Using a sample of 100 fluted bifaces of Clovis and post-Clovis styles in the eastern United States ca. 13,100–9,000 cal BP (i.e., Clovis, Debert-Vail, Bull Brook, Michaud-Neponset/Barnes, and Crowfield), we employed two different approaches for statistical shape analysis: our previously presented method for analysis of 2D flake scar contours, and a new approach for 3D surface analysis using spherical harmonics (SPHARM). Whereas bifacial asymmetry in point shape does not vary significantly across this stylistic sequence, our measure of asymmetric flake scar patterning shows temporal variation that may signify the beginning of regionalization among early New World colonists.


Presse zB
http://www.heritagedaily.com/2017/0...among-early-north-american-stone-tools/116159
 
Nachgetragen: die Santa-Elina- Untersuchung aus der Antiquity:


Peopling South America's centre: the late Pleistocene site of Santa Elina


Der Beitrag datiert die archäologisch untersuchte Örtlichkeit bezüglich der Population auf älter als 20.000 Jahre. Wenn das mit den Beringia-Wellen in Einklang gebracht werden soll, wäre das Zeitfenster einer Nord-Süd-Besiedlung der Kontinente auf ein oder zwei Dutzend Jahrhunderte beschränkt.

Oder es gab eine frühere erste Welle... oder eine afrikanische, von der keine populationsgenetischen Spuren existieren??

Presse:
People may have lived in Brazil more than 20,000 years ago
 
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Die Süßkartoffel im Südpazifik ist als "Indiz" für einen präkolumbischen Kontakt zu Südamerika nach der neusten genetischen Studie nun erledigt. Die Studie bestätigt die Vermutungen, dass es die Kartoffel ohne menschliches Zutun in den Südpazifik geschafft hat (vor einiger Zeit hatten wir übrigens einen anderen Fall einer Spinnenart zwischen Afrika und Australien ohne "Landweg").

Die Süßkartoffel verbeitete sich dorthin etwa vor 100.000 Jahren.
Reconciling Conflicting Phylogenies in the Origin of Sweet Potato and Dispersal to Polynesia
 
Eine neue Publikation aus der ScienceAdvances berichtet über Ausgrabungen in Texas, Baylor University.

Untersucht wurden Pre-Clovis-Speerspitzen, die auf 15000 BP datiert werden, und damit die ältesten solcher Speerspitzenfunde in Nordamerika darstellen würden.

Publikation
Pre-Clovis projectile points at the Debra L. Friedkin site, Texas—Implications for the Late Pleistocene peopling of the Americas

Presse, zB
Amerika: Die Speerspitze der ersten Einwanderer
Early Spear Points Discovered in Texas - Archaeology Magazine
Spear Points Discovered in Texas Are the Oldest Weapons Found in North America
 
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