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Murray, Alexandr P. Phylogenies are usually dated by calibrating interior nodes against the fossil record. This relies on indirect methods that, in the worst case, misrepresent the fossil information.


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Evidence is building that its origin as a zoonotic spillover occurred prior to the officially accepted timing of early December, We show that six countries had exceptionally early cases, unlikely to represent part of their main case series. Origination dates are discussed for the first five countries outside China and each continent.

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We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings. Published online by Cambridge University Press: 20 May Four excavations have been performed at the archaeological site of Cova Rosa Asturias, Cantabrian Spain : three of them in the second half of last century and the other in this decade. Although little of the archaeological material found in those excavations has been published, here we attempt the stratigraphic correlation of sections revealed by the different excavations and we present 22 new radiocarbon dates for bones and marine shells, built in a Bayesian statistical model.

This has enabled the documentation of occupations that mainly took place during the Last Glacial period, in the Solutrean middle and upper phases and Magdalenian archaic, lower, and upper phasesand also in the early Holocene Mesolithic. These occupations are compared with the record at other sites in Cantabrian Spain in general and in Asturias, in particular. In the last decade, one of the areas in the Iberian Peninsula in which knowledge of prehistoric hunter-gatherer groups has advanced most is the Sella valley, particularly as regards the transition from the Upper Pleistocene to the early Holocene.

Radiocarbon dates for the late pleistocene and early holocene occupations of cova rosa (ribadesella, asturias, spain)

This valley, in the east of the Principality of Asturias northern Spainis the location of one of Rosa densest concentrations of prehistoric sites in caves and rock-shelters in the whole of the Cantabrian region e. Figure 1 Map of Northern Spain and the Sella River valley in the east of the Principality of Asturias, indicating the most important archaeological sites with occupations during the Late Pleistocene and Early Holocene. Cova Rosa is located in the lower Sella valley. The remains found during the latter two series of excavations are currently being studied by an interdisciplinary team based at the University of Salamanca.

Researchers from the same university have again been excavating and sampling the site since The objectives of the present paper are: first, to provide an updated stratigraphic sequence for the Palaeolithic deposit in Cova Rosa, based on a new lithostratigraphic study carried out at the site and its correlation with the stratigraphic sequences presented by past researchers; and second, to present a series of radiocarbon dates that cover all the levels in the sequence and thus place them precisely on the Upper Pleistocene chronoclimate scale.

Therefore, a total of 22 radiocarbon dates are presented here, obtained for samples of bones and shells from the archaeological levels documented by dating excavations in and —, and in the recent fieldwork, in These dates provide precise ages for the different occupations in the cave, which have been attributed to the Solutrean, Magdalenian and Mesolithic, based on the archaeological remains found. They also contribute to understand the characteristics of the occupation of the Sella valley in the context of northern Spain, in the late Pleistocene and early Holocene. It is 4 km in a straight line from the current coastline, about 3km from the neighboring caves with model deposits of Les Pedroses and El Cierro and 5.

Reference Navarro, Leyva, Villa and Granados It is a large rock-shelter, 25 m wide and 15 m high, which gives access to the cave of the same name, whose entrance is now blocked and can only be accessed with speleological techniques. The small river flowing in the blind valley currently sinks into the karst 23 m below the rock-shelter, whereas in the Pleistocene the sink was through the rock-shelter.

The Cova Rosa karst complex is a long cave system through which the San Miguel River circulates before resurging in the village of Soto. Cova Rosa currently shelters an important bat colony protected under the legal figure of Reserva Natural Parcial de Cova Rosa.

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Cova Rosa was discovered in by FJC. These remains were studied by P. Utrilla Reference Utrilla and L. Additionally, P. Utrilla Reference Utrilla and C. FJC excavated in Cova Rosa again in He did not reach the bedrock of the cave. They documented nine levels, named Cova Rosa A to I. These excavations were carried out following the method of Cartesian coordinates Laplace Reference Laplace and by subjecting all the extracted sediments to a triple sieve screening.

They were provisionally ascribed to the Final Magdalenian-Azilian. Additionally, in order to continue the excavation with more ease, Square D4 was excavated, and the whole sequence was documented in that area, from the clays at the base to the top.

FJC did not date, by radiocarbon or any other method, the archaeological levels that he documented in the different excavations that his team carried out in Cova Rosa during the second half of the last century. Since the University of Salamanca has again being carrying out archaeological fieldwork in the cave with the objectives of cleaning up the excavated surfaces and the stratigraphic sections that were still intact, and of collecting different kind of samples Figure 2.

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The refreshed sections were those in the outer face south section of the excavation and the south and east sections in Square D4 of the — excavations. In addition, staff from the Archaeozoology Laboratory at the University have collected samples of bones and shells from the archaeological levels documented during the last century in and in the — excavations in order to determine the chrono-stratigraphic position of the artifacts found in the past and correlate them with the finds from the new archaeological fieldwork.

It shows the approximate place of the excavations carried out by F. These six units correspond to the six main levels defined by the geologist MHG in his doctoral thesis, which were named with capital letters from A to F and which in total reached a maximum thickness of about 1.

Figure 3 shows the correlation established between the levels described by the researchers who worked in Cova Rosa ly FJC in and ; FJC, AGF, and MHG from to and the units of our own lithostratigraphic sequence obtained in Clear erosive contacts between some of the stratigraphic units, their textural characteristics clasts and matrix and their colour facilitated the correlation. Figure 3 Stratigraphic correlations across the three excavations at Cova Rosa.

From bottom to top, the lithostratigraphic units observed in the south section in Square D4, where the cave bedrock has not been reached, is as follows Figure 4 :. Very light brown massive silty clay with autochthonous limestone clasts. Polyhedral autochthonous limestone pebbles and plaquettes with sharp edges arranged horizontally, in a dark grey-black silty clay matrix.

Polyhedral autochthonous limestone pebbles with sharp edges, in an abundant brown silty clay matrix. Polyhedral autochthonous limestone boulders and pebbles with sharp edges, and some plaquettes. Abundant grey-black silty clay matrix.

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Polyhedral autochthonous limestone pebbles with sharp edges, in a grey silty clay matrix. The contact with the underlying layer is clearly erosive.

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Light beige silts and clays with a massive appearance and very compact. Some polyhedral autochthonous limestone pebbles with sharp edges and some very rounded ones.

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Limestone plaquettes also appear. The surface of the contact with the underlying layer is erosional.

Angular autochthonous limestone boulders and rocks, with plaques and clasts that have fragmented after their sedimentation. The matrix is formed by very compact light beige silt and clay with a massive appearance. This layer only appears in the western part of the south section, towards the interior of the cave and outside Square D4. Figure 4 Stratigraphic section of the excavation at Cova Rosa. A few remains of a strongly cemented shell-midden CR-conch. Therefore, a large stratigraphic gap exists between the deposit that forms the fill in the rock-shelter and the organogenic deposit of this shell-midden; this would be the consequence of erosion after their sedimentation.

In turn, the shell-midden CRconch. Shell and bone samples were chosen for radiocarbon dating as those remains have been found in abundance in the different excavations carried out in Cova Rosa. The preferred dating material was bone and, wherever possible, we selected bones for which the taxon and anatomical element could be identified and which displayed cutmarks as evidence of anthropic activity.

However, in the uppermost layers excavated in — A0, B1 and B6 marine mollusk shells were selected instead, either the periwinkle Littorina littoreaor the common limpet, Patella vulgata.

Materials and methods

This was because osseous remains in those layers were fragmented and altered by natural agents and post-depositional processes the cave was used as an animal pen until quite recently. In the case of the fieldwork, the only shell sample Phorcus lineatus came from the small remnants of a shell-midden adhered to the rock-shelter wall of the cave, where only mollusk shells have been documented. Charcoal fragments that could potentially be dated were also recovered in the and — excavations.

Their presence was recorded in the excavation logbooks and has been confirmed in the sediment floating and screening process. They are currently being studied. Reference Brock, Higham, Ditchfield and Ramsey The shells OxA, 31, 31, 31, underwent the pretreatment for biogenic carbonates as this is applied at the ORAU phosphoric acid dissolution. In the case of bone samples, some were dated using ultrafiltration OxA, 38, 38, 38, 38, 39, 39, 39, and the rest using the simpler ABA method ABA: OxA, 38, 38, 38, 38, 38, 38, The selection of the ABA method over ultrafiltration was based on the physical inspection of each sample and the assumption that some bones may not preserve sufficient collagen.

This turned out not to be true as collagen yields ranged between 1. The radiocarbon have been subjected to a validity test Mestres Reference MestresReference MestresReference MestresReference Mestres to determine that they meet the basic requirements for such dates. These requirements are of chemico-physical, analytical and archaeological types.

Article contents

The chemico-physical requirements refer to the capacity of the material to provide a valid radiocarbon date. The 22 samples from Cova Rosa are all organic materials 18 bone fragments and 4 mollusk shells and therefore satisfy those conditions perfectly. The analytical requirements that radiocarbon dates should meet refer to their accuracy elimination of contamination, chemical treatment and measurement of the 14 C content and precision standard deviation and are related to laboratory quality control.

The requirement of precision specifies that the standard deviation of the radiocarbon should be as small as possible. This is met by the provided by the ORAU, as the deviations are smaller than or equal to years, which is considered reasonable for this time in the Pleistocene.

Two are smaller than 50 years, seven are between 50 and 65, eight between 80 and 90, and five are larger than 90 radiocarbon years. Finally, in archaeological terms, a radiocarbon date should be representative of the event that it is attempting to determine chronologically. That is to say, a close correspondence should exist between the physical age of the dated sample and the archaeological age of the context or event being dated.