Research projects ongoing Extreme wave events Cyclone-generated washover sediments and landforms of Western Australia. Scheffers Lismore, Australia , D. Kelletat Cologne , M. Participating scientists in working group: Paleo-tsunami and earthquake records of ruptures along the Nankai Trough, offshore South-Central Japan. Hubert-Ferrari Belgium , O. Yokoyama Japan , H. Engel Cologne , R.
Two big stories have already hit the news in January. On the morning of July 19, , French scientist Alain Beauvilain and three Chadian colleagues discovered a fossil cranium in the dunes of the Chadian Sahara Desert, together with an assemblage of other fossils. The sensational discovery was covered by worldwide media, and the discoverer wrote a popular science book Beauvilain about the story of the find.
It was shortly thereafter described by the head of the research team, Michel Brunet Brunet et al. Geological and paleontological evidence Vignaud et al. The smashed fossil thus achieved iconic status.
The cosmogenic burial dating method makes use of the difference in half-life of two (or more) cosmogenic nuclides in sediments that had have been buried after a period of exposure and thus cosmogenic nuclide production.
A number of radioactive isotopes are used for this purpose, and depending on the rate of decay, are used for dating different geological periods. More slowly decaying isotopes are useful for longer periods of time, but less accurate in absolute years. With the exception of the radiocarbon method , most of these techniques are actually based on measuring an increase in the abundance of a radiogenic isotope, which is the decay-product of the radioactive parent isotope.
Two or more radiometric methods can be used in concert to achieve more robust results. This technique measures the decay of carbon in organic material and can be best applied to samples younger than about 60, years. This technique measures the ratio of two lead isotope s lead and lead to the amount of uranium in a mineral or rock. Often applied to the trace mineral zircon in igneous rocks , this method is one of the two most commonly used along with argon—argon dating for geologic dating.
Radiometric dating By measuring the amount of radioactive decay of a radioactive isotope with a known half-life , geologists can establish the absolute age of the parent material. A number of radioactive isotopes are used for this purpose, and depending on the rate of decay, are used for dating different geological periods. More slowly decaying isotopes are useful for longer periods of time, but less accurate in absolute years.
With the exception of the radiocarbon method , most of these techniques are actually based on measuring an increase in the abundance of a radiogenic isotope, which is the decay-product of the radioactive parent isotope.
Sep 14, · Lebatard et al. – Cosmogenic nuclide dating of Sahelanthropus tchadensis and Australopithecus bahrelghazali: Mio-Pliocene hominids from Chad, , link Fast Breaking Comments, , By Martin Pickford.
The first arrivals of hominin populations into Eurasia during the Early Pleistocene are currently considered to have occurred as short and poorly dated biological dispersions. Questions as to the tempo and mode of these early prehistoric settlements have given rise to debates concerning the taxonomic significance of the lithic assemblages, as trace fossils, and the geographical distribution of the technological traditions found in the Lower Palaeolithic record. We argue that distinct technological traditions coexisted in the Iberian archaeological repertoires of the late Early Pleistocene age in a similar way to the earliest sub-Saharan African artefact assemblages.
These differences between stone tool assemblages may be attributed to the different chronologies of hominin dispersal events. Up to now, chronology of the earliest European LCT assemblages is based on the abundant Palaeolithic record found in terrace river sequences which have been dated to the end of the EMPT and later. However, the findings at Barranc de la Boella suggest that early LCT lithic assemblages appeared in the SW of Europe during earlier hominin dispersal episodes before the definitive colonization of temperate Eurasia took place.
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Rain rates, runoff and soil humidity contribute on unknown terms to a sudden collapse opening holes on the ground with a diameter of several meters jeopardising severely civil engineering communication works. DAIS hyperspectral spectrometer data have been used to identify areas prone to doline collapse in a carbonate flat area in central Spain. Decreasing carbonate and increasing clay contents are spectrally recorded both in the field and the imagery.
Field spectra using a GER spectrometer have been used with Spectral Angle Mapper digital mapping procedures to identify such areas.
Cosmogenic nuclide burial dating [an analysis based on changes induced by exposure to the sun, which yielded an age near 4 million years] has so far not given good results, probably because chert clasts included in breccia have different origins.”.
The evolution of landscapes in the high Arctic is a complex process that takes place over long timescales and by multiple mechanisms. Corbett and colleagues investigate the age and history of the landscape in northwestern Greenland in order to understand how it has evolved over time and how effectively glaciers have shaped it. They use beryllium and aluminum , two rare isotopes that are produced in rocks when they are exposed to bombardment by high-energy cosmic rays from space.
By quantifying the concentrations of these two isotopes, they make inferences about how much time the landscape has spent buried beneath glacial ice versus how much time it has spent exposed. Corbett and colleagues conclude that the landscape in Upernavik is very old; some locations preserve a record of almost one million years. This contrasts greatly with many other landscapes in Greenland, which date back only to about 10, years ago the end of the last glacial period.
They also conclude that the land surfaces in Upernavik have been preserved beneath non-erosive glacial ice throughout many glacial periods over the course of geologic time. These so-called “ghost glaciers” cover the landscape but are incapable of eroding it, leaving behind no geologic evidence of their presence. Detrital zircon evidence for non-Laurentian provenance, Mesoproterozoic ca. Defining the Picuris orogeny Christopher G. Posted online 23 July ; http:
Bulk changes produced by weathering in granitic rocks have been studied by several methods, including chemical weathering indices. They are based on the assumption that some ions are more easily leached from minerals in relation to others. Such methods have also been briefly tested on building stone but not in urban environments, where fast stone weathering rates are typically observed, mainly due to interaction of minerals with several pollutants and where other specific processes, such as salt weathering, can occur.
The aim of this work is to discuss the use of weathering indices in the study of weathering rates on granitic stones applied in four historical buildings of an urban area. Results suggest that some factors can cause scatter of results in the relation indices vs. Indices that consider some highly mobile cations that are present in other building materials namely Ca that is related to leaching from mortar joints should be avoided due to the uptake of such elements by the stone pores or used to assess this some types of weathering.
classical architecture and archaeology Neil Diamond, and Carole King, the singer-songwriter tradition in fact has a long and complex history dating back to the medieval troubadour and earlier. This Companion explains the historical contexts, musical analyses, and theoretical frameworks of the singer-songwriter tradition. Divided into five.
The discovery may change existing ideas about the earliest arrival of human ancestors from Africa into India. One hundred and fifty years ago, on May 30, , young geologist Robert Bruce Foote bent down and picked up a stone tool on the Parade Ground at Pallavaram cantonment, near Chennai. It turned out to be an epochal discovery. Discovered in September , by Robert Bruce Foote and his colleague William King, it was investigated in the early to mid 20th century by several scholars- T.
Later work on the prehistory of this region was conducted by A. A team of Indian and French archaeologists have used two dating methods including Cosmogenic nuclide burial dating to show that the stone hand-axes and cleavers from Attirampakkam are at least 1. Archaeologists Shanti Pappu and Kumar Akhilesh from the Sharma Centre for Heritage Education have spent the last 12 years continuing to excavate the site and have now found 3, artefacts that bear a distinct similarity to prehistoric tools discovered in western Asia and Africa.
The tools fall into a class of artefacts called Acheulian that scientists believe were first created by Homo erectus — ancestors of modern humans — in Africa about 1. Petraglia himself had earlier been involved in excavating the Hunsgi valley in Karnataka, which has yielded 1. Although earlier excavations had revealed Acheulian tools at a few sites on the Indian subcontinent, including a two million-year-old site in Pakistan, the dates assigned to the artefacts so far have remained under debate.
Researchers believe the new dates will have major implications for current ideas about who carried the Acheulian culture into India. In the past, some researchers had attributed the flow of Acheulian tools into southern Asia and Europe to the Homo heidelbergensis, another ancestor of modern humans but one that appeared long after the Homo erectus.
In an independent research study, Petraglia and his colleagues have analysed Acheulian tools in India that appear to be only , years old. The two findings suggest that the Acheulian toolmakers inhabited India for 1.
The unit II lithofacies, with its poorly stratified sands and gravels, indicates subaerial and subaquatic mass flow deposits which are often described in alluvial fan and fan-delta sedimentary environments . An aquatic environment is further suggested by the presence of hippopotamuses and water voles found in the LM and EF localities. The Early Pleistocene occupation of analogous flooded areas suggests a hominin preference for this habitat type as is also suggested by other studies of the palaeoecology of Lower Palaeolithic hominins .
Field studies at Barranc de la Boella archaeological project did not involve endangered or protected species.
Several presentations on Radiocarbon Dating, Iodine, Oceans and Coastlines and Cosmogenic Radionuclides. IUAC Workshop on Accelerator Mass Spectrometry. .
The answer may depend on whether they used make-up. Francesco d’Errico, an archaeologist from the University of Bordeaux, France, has found crafted lumps of pigment — essentially crayons — left behind by Neanderthals across Europe. He says that Neanderthals, who most likely had pale skin, used these dark pigments to mark their own as well as animal skins.
And, since body art is a form of communication, this implies that the Neanderthals could speak, d’Errico says. These add to evidence of pigment among Neanderthal from some 39 other sites. The pigments were not just smeared onto the body like camouflage, d’Errico says, but fashioned into drawing tools. Body painting, argues d’Errico, is a “material proxy” for symbolic communication. What’s more, he says, the techniques for making the symbols, and the meaning they carry, would have to be transmitted through language.
And body painting isn’t the only proxy associated with Neanderthal remains. Neanderthals adorned their bodies with ornamentation, such as necklaces made from shell beads. The sorts of beads used by modern humans, and the ornaments they fashioned from them, vary geographically. This is often interpreted as a sign of ethnic and cultural diversity among humans, and a means of symbolically binding groups and differentiating them from others.