Continuous Chronology Research Articles

Developing millennial tree-ring chronology for Turku (Åbo) and comparing palaeoclimaticsignals inferred from archaeological, subfossil and living Pinus sylvestris datain Southwest Finland

Archaeological and living tree data were used to construct tree-ring chronologies over the medieval (AD 1183–1430) and recent (AD 1812–2020) periods in Turku, which is historically an important population centre in Southwest Finland and the country. Comparisons between the two tree-ring assemblages, and between the previously built chronologies from the Åland (historical timber) and Tavastia (lacustrine subfossils and living trees) sites, provided ways of understanding the growth patterns and their linkages to climatic, environmental, and edaphic factors. Tree growth in and around Turku was affected by warm-season precipitation and winter temperature. Similar relationships were previously evident also in the Åland tree rings, whereas the data from a wetter Tavastia site did not exhibit similar precipitation signal. The site conditions influence also the correlations which are higher between Turku and Åland than between Turku and Tavastia chronologies. Construction of long continuous chronology is impaired by human-related activities, the Great Fire of Turku in 1827 and logging, which have diminished the availability of dead and living-tree materials, respectively. These conditions lead to hardships of filling the gap between the medieval and recent periods and updating the archaeological datasets with compatible living-tree data, which are both demonstrated by our results.

Early Holocene ice on the Begguya plateau (Mt. Hunter, Alaska) revealed by ice core 14C age constraints

Abstract. Investigating North Pacific climate variability during warm intervals prior to the Common Era can improve our understanding of the behavior of ocean–atmosphere teleconnections between low latitudes and the Arctic under future warming scenarios. However, most of the existing ice core records from the Alaskan and Yukon region only allow access to climate information covering the last few centuries. Here we present a surface-to-bedrock age scale for a 210 m long ice core recovered in 2013 from the summit plateau of Begguya (Mt. Hunter; Denali National Park, Central Alaska). Combining dating by annual layer counting with absolute dates from micro-radiocarbon dating, a continuous chronology for the entire ice core archive was established using an ice flow model. Calibrated 14C ages from the deepest section (209.1 m, 7.7 to 9.0 ka cal BP) indicate that basal ice on Begguya is at least of early Holocene origin. A series of samples from a shallower depth interval (199.8 to 206.6 m) were dated with near-uniform 14C ages (3 to 5 ka cal BP). Our results suggest this may be related to an increase in annual net snow accumulation rates over this period following the Northern Hemisphere Holocene Climate Optimum (around 8 to 5 kyr BP). With absolute dates constraining the timescale for the last >8 kyr BP, this paleo-archive will allow future investigations of Holocene climate and the regional evolution of spatial and temporal changes in atmospheric circulation and hydroclimate in the North Pacific.

The Monongahela tradition in "real time": Bayesian analysis of radiocarbon dates.

Despite advances in techniques, methods, and theory, northeastern North American archaeologists continue to use early to mid-twentieth century culture historical taxa as units of analysis and narrative. There is a distinct need to move away from this archaeological practice to enable fuller understandings of past human lives. One tool that enables such a move is Bayesian analysis of radiocarbon dates, which provides a means of constructing continuous chronologies. A large dataset of radiocarbon dates for late prehistoric (ca AD 900/1000–1650) sites in the lower upper Ohio River basin in southwestern Pennsylvania and adjacent portions of Maryland, Ohio, and West Virginia is used here as an example. The results allow a preliminary assessment of how the settlement plans of contemporaneous villages varied considerably, reflecting decisions of the village occupants how to structure built environments to meet their needs.

Impacts of land-cover changes on snow avalanche activity in the French Alps

Abstract Dendrogeomorphic analyses provide long and continuous chronologies of mass movements that are useful for the detection of trends related to climate change. Socio-environmental changes can, however, induce non-stationarities. This study addresses the following questions: (1) How does the evolution of forest cover induce non-stationarities in tree-ring based reconstructions of snow avalanche activity? (2) How are trends inherent to tree-ring approaches distinguishable from real fluctuations in avalanche activity? Using dendrogeomorphic techniques, we reconstructed snow avalanches in six adjacent paths in the French Alps. Results show two distinct trends in process activity between 1750 and 2016. In the southern paths, the frequency of snow avalanches increased sharply in the 1970s. The distribution of tree ages, as well as old topographic maps, allow an attribution of this trend to the destruction of large parts of the forest stand by a large snow avalanche in the 1910−20 s. This extreme event induced a sudden change in the capability of newly colonizing trees to record subsequent snow avalanches. In the northern paths, by contrast, progressive afforestation starting in the mid-19th century, as well as colonization of the release areas after World War II, resulted in a strong reduction in snow avalanche activity since the 1930s. Even if global warming remains a possible additional driver of snow avalanche activity at the study sites, the rural exodus and the abatement of pastoral practices during the 19th and 20th centuries are the main explanations for the observed trends in process activity. Results also illustrate a need to clarify the complex interrelations among forest evolution, global warming, social practices, and the process activity itself when interpreting trends in mass movements.

Early Palaeozoic diversifications and extinctions in the marine biosphere: a continuum of change

AbstractA review of biodiversity curves of marine organisms indicates that, despite fluctuations in amplitude (some large), a large-scale, long-term radiation of life took place during the early Palaeozoic Era; it was aggregated by a succession of more discrete and regionalized radiations across geographies and within phylogenies. This major biodiversification within the marine biosphere started during late Precambrian time and was only finally interrupted in the Devonian Period. It includes both the Cambrian Explosion and the Great Ordovician Biodiversification Event. The establishment of modern marine ecosystems took place during a continuous chronology of the successive establishment of organisms and their ecological communities, developed during the ‘Cambrian substrate revolution’, the ‘Ordovician plankton revolution’, the ‘Ordovician substrate revolution’, the ‘Ordovician bioerosion revolution’ and the ‘Devonian nekton revolution’. At smaller scales, different regional but important radiations can be recognized geographically and some of them have been identified and named (e.g. those associated with the ‘Richmondian Invasion’ during Late Ordovician time in Laurentia and the contemporaneous ‘Boda event’ in parts of Europe and North Africa), in particular from areas that were in or moved towards lower latitudes, allowing high levels of speciation on epicontintental seas during these intervals. The datasets remain incomplete for many other geographical areas, but also for particular time intervals (e.g. during the late Cambrian ‘Furongian Gap’). The early Palaeozoic biodiversification therefore appears to be a long-term process, modulated by bursts in significant diversity and intervals of inadequate data, where its progressive character will become increasingly clearer with the availability of more complete datasets, with better global coverage and more advanced analytical techniques.

Tree-ring reconstruction of snow avalanche activity: Does avalanche path selection matter?

In the current context of anthropogenic global warming, one of the purposes of dendrogeomorphic analyses is to provide long and continuous chronologies of mass movements, so as to detect potential trends or shift related to increasing temperatures. However, on documented slopes, the comparison between historical archives and tree-ring records suggests that dendrogeomorphic reconstructions systematically underestimate the natural activity of the process under investigation. In the specific case of snow avalanches, underestimation generally amounts to 50% and the main causes generally given for this difference are related to the magnitude of past events. In this study, we hypothesize that the morphometric characteristics of avalanche paths and their forest cover could have significant impacts on the length and reliability of tree-ring reconstructions. In order to test this hypothesis, we selected four adjacent, albeit differently structured, avalanche paths from the Queyras massif (French Alps), with the aim to compare their potential for a continuous reconstruction of past avalanche activity. On the most active avalanche paths characterized by high-altitude release areas (covered only by shrubby vegetation), tree-ring reconstructions do not exceed one century in length, with recurrence intervals of high magnitude events >25 years. By contrast, on forested couloirs where lower slopes and forest coverage up to the release areas limits the intensity of events, the frequency of reconstructed snow avalanches is 2.5 times higher, the reconstructions span longer periods and the convergence rate with historical archives attest to the reliability of the dendrogeomorphic approach. These results suggest that a careful selection of couloirs is essential and that priority should be given to forested sites as (i) they allow for exhaustive and (ii) reliable reconstructions over (iii) long periods of time.

A millennium-long perspective on high-elevation pine recruitment in the Spanish central Pyrenees

Long-term fluctuations in forest recruitment, at time scales well beyond the life-span of individual trees, can be related to climate changes. The underlying climatic drivers are, however, often understudied. Here, we present the recruitment history of a high-elevation mountain pine (Pinus uncinata Ram.) forest in the Spanish central Pyrenees throughout the last millennium. A total of 1108 ring-width series translated into a continuous chronology from 924 to 2014 CE, which allowed estimated germination dates of 470 trees to be compared against decadal-scale temperature variability. High recruitment intensity mainly coincided with relatively warm periods in the early 14th, 15th, 19th, and 20th centuries, whereas cold phases during the mid-17th, early 18th, and mid-19th centuries overlapped with generally low recruitment rates. In revealing the importance of prolonged warm conditions for high-elevation pine recruitment in the Pyrenees, this study suggests increased densification and even possible upward migration of tree-line ecotones under predicted global warming.

The importance of radiocarbon dates and tephra for developing chronologies of Holocene environmental changes from lake sediments, North Far East

Developing continuous chronologies of paleoenvironmental change in northern areas of the Far East using 14C can be problematic because of the low organic content in lake sediments. However, Holocene age-models can be supplemented by widespread tephra deposits reported in the Magadan region. The best documented of these tephras has been correlated to the KO tephra from southern Kamchatka dated to 7600 BP. Although a key chronostratigraphic marker, no detailed compendium of the distribution of this tephra and its associated 14C dates has been available from sites in the northern Far East. We provide such a summary. Known locally as the Elikchan tephra, lake cores indicate an ash fall that extended ~1800 km north of the Kamchatkan caldera with a ~500 km wide trajectory in the Magadan region. Other Holocene tephras preserved in lake sediments have poorer age control and possibly date to ~2500 BP, ~2700 BP and ~6000 BP. These ashes seem to be restricted to coastal or near-coastal sites. A single record of a ~25,000 BP tephra has also been documented ~100 km to the northeast of Magadan.

Recent advances in long-term climate and moisture reconstructions from the Baltic region: Exploring the potential for a new multi-millennial tree-ring chronology

This study presents the first results from an ongoing initiative to develop a multi-millennial Baltic tree-ring width (TRW) chronology consisting of 12 floating records from subfossil Scots pines (Pinus sylvestris L.) extracted from three Lithuanian peat-mining areas. The floating series have been complemented with absolutely dated TRW chronologies which were obtained from living trees growing in unmanaged and unexploited peatland areas adjacent to each of the above study sites. The subfossil material has been dated by radiocarbon and shows a temporal spread over the last 6000 years, with assemblages of trees during the Holocene Thermal Maximum (HTM; 8000-4000 BP) and the onset of the Medieval Warm Period (MWP, AD 900–1350). Annual tree growth and sample replication of peatland pines reflect moisture variations and long-term climate variability. The importance of extending the TRW chronologies should not therefore be underestimated as (1) climate records of comparable length and resolution do not exist for the Baltic region, but also as (2) a result of a widespread lack of detailed moisture proxies spanning several millennia. Our data clearly show that a 6000-yr, continuous pine chronology from the Baltic region is a realistic objective, and would doubtlessly fill a major geographic gap in an ecologically sensitive region located at the interface between the temperate and boreal vegetation zones.

An automated algorithm for dating annually laminated sediments using X-ray radiographic images, with applications to Lake Van (Turkey), Lake Nautajarvi (Finland) and Byfjorden (Sweden)

Annually laminated (varved) sediments in marine and lake basins are important archives for paleoenvironmental and paleoclimatic reconstructions, especially with their property to provide a continuous chronology. In this study we introduce a new approach for counting laminae using both digital and analogue X-ray radiographic images. The requirement for the method is that the resolution of the image is higher than the minimum lamina thickness, so that the measurement interval should be at least one third of the minimum lamina thickness. In our method, 8-bit or 16-bit grey scale radiographic images are scaled to grey-scale values between 0 and 1, and every maximum and minimum peaks corresponding to seasonal lamination are defined along the sediment core. The algorithm counts laminae rather than varves, thus allowing control on estimation of more reliable age models. Detected peaks are summed cumulatively along the core length, using a step determined by the annual lamina number of the varve.Using the algorithm, we provide test examples from the varved sediments of the Lake Nautajarvi in Finland, Byfjorden in Sweden and Lake Van in eastern Turkey, and compare our results with previously dated levels in the cores. There are good agreements between the varve counting results of our study and the previous studies, except for the ages from the lower part of the Lake Van core corresponding to a time interval between ca. 7000 and 8000 BP, for which there is ca 1000 year difference between the two sets of results. This difference might be the result of under-counting of varves in the previous studies.

Deciphering human–climate interactions in an ombrotrophic peat record: REE, Nd and Pb isotope signatures of dust supplies over the last 2500 years (Misten bog, Belgium)

A high-resolution peat record from Eastern Belgium reveals the chronology of dust deposition for the last 2500years. REE and lithogenic elements in addition to Nd and Pb isotopes were measured in a 173cm age-dated peat profile and provide a continuous chronology of dust source and intensity. Calculated dust flux show pronounced increases c. 300BC, 600AD, 1000AD, 1200AD and from 1700AD, corresponding to local and regional human activities combined with climate change.The Industrial Revolution samples (1700–1950AD) are characterised by a significant enrichment in Sc-normalised REE abundance (sum REE/Sc>25) due to intensive coal combustion. For the pre-Industrial Revolution samples, the Sc-normalised REE abundance (10<Sum REE/Sc<25) and the εNd variability (−13 to −9) are interpreted by a mixing between dust particles from local soils and long-range transport of desert particles. Three periods characterised by dominant-distal sources (c. 320AD, 1000AD and 1700AD) are consistent with local wetter-than-average intervals as indicated by a lower degree of peat humification. Local erosion prevails during the drier (higher humification) intervals (100AD, 600AD). On a global scale, more distal supplies are driven during colder periods, in particular during the Oort and Maunder minima, suggesting a potential link between dust deposition and global climate. Combining REE abundance, fractionation between Light REE and Heavy REE and Nd isotope data in ombrotrophic peat allows one to distinguish between dust flux changes related to human and climate forcings.

Tree-ring study of a Late Holocene forest buried in the Ubuka Basin, southwestern Japan

Buried trees in the Ubuka Basin, southwestern Japan, were investigated to identify the wood species and to build tree-ring chronologies. A total of 65 trees were collected belonging to three species: Japanese cedar (Cryptomeria japonica, 63 trees), Japanese nutmeg tree (Torreya nucifera, one tree) and Hinoki cypress (Chamaecyparis obtusa, one tree). Crossdating of the individual ring-width series resulted in four independent tree-ring chronologies covering 605, 576, 507 and 395 years. The absolute ages of these chronologies were determined to be 3676, 4166, 4576 and 4876 cal BP by definite-gap sequence modeling of radiocarbon dates measured at a constant gap of 30 years. An extremely long, continuous chronology can probably be developed in the future by increasing the number of samples at this site.

Resolving the Holocene alluvial record in southeastern Australia using luminescence and radiocarbon techniques

AbstractA previous assessment of radiocarbon (14C) dates from alluvial units in southeastern Australia revealed a gap in the geochronological record that coincides with the Holocene climatic optimum. This gap in the alluvial record can be further refined using optically stimulated luminescence (OSL). The chronology of Holocene river terraces on Widden Brook, a sandy alluvial stream in southeastern Australia, was established using 14C and OSL techniques. Combined use of these independent techniques allows for a more rigorous assessment of the alluvial record. The robust chronology, consisting of 38 14C and 11 OSL samples, permitted identification of significant depositional variation within the catchment, resulting from localised geomorphic processes. The three terrace sequences identified yielded distinct chronologies, suggesting alluvial deposition at different times. The sequences exhibited a continuous chronology, which indicated continuous deposition throughout the Holocene. The chronology of terrace sequences within this catchment suggests that terrace formation can be attributed to localised geomorphic processes rather than climatic forcing. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Geochemical variations in late-stage growth of volcanic phenocrysts revealed by SIMS depth-profiling

In the petrologic and geochemical study of volcanic rocks, microlites have become an important tool with which to determine magma decompression rate and ascent path prior to eruption. However, studies in experimental petrology and kinetic modeling indicate that growth of pre-existing phenocrysts will occur over a much wider range of decompression-induced undercoolings than microlite nucleation. Consequently, we have developed a method using secondary ion mass spectrometry (SIMS) depth profiling to measure geochemical trends recorded during the final stage of phenocryst growth. To test and demonstrate the new method, we examined explosive and effusive eruptive products collected from Soufrière Hills volcano, Montserrat. Plagioclase feldspar crystals were removed from clasts of pyroclastic deposits. Phenocrysts were individually selected on the basis of euhedral morphology and a relatively homogeneous distribution of surface contamination, such as volcanic glass. Crystals were cleaned, embedded in In, and analyzed by SIMS in depth-profiling mode. We used an O 2+ primary ion beam, which provides a faster sputtering rate than the typically utilized O - primary beam. A normal-incidence electron gun is used for charge compensation. Ten isotopes were examined over 2-10 h periods and the resulting crater depth was determined. Data show variable trends in An, K, and Fe that we interpret to represent late-stage physical variations within the magma prior to eruption. The continuous chronology of geochemical data obtained from the SIMS analyses presented here provide information with unprecedented (~0.1 μm) resolution, allowing researchers to determine physical conduit conditions during magma ascent from the chamber to eruption at the surface

Stalagmite lamina doublets: a 1000 year proxy record of severe winters in northwest Scotland?

AbstractStalagmites can contain annual luminescence laminae, and some samples provide long continuous chronologies from which climatic information can be extracted. One such site is Uamh an Tartair in Assynt, northwest Scotland, where most stalagmites contain continuous laminae sets for the last two to three millennia. At this site, the normal mode of deposition is for one luminescent lamina to be deposited in autumn, derived from luminescent organic matter that is flushed onto the sample from the overlying peat. However, in the stalagmite investigated here, 43 lamina doublets occur, where two laminae appear to be preserved in a winter. We argue, both from the timing of these events within the ‘Little Ice Age’, as well as from analogous situations in alpine streams, that the doublets occur due to the presence of a second, spring melt flush of organic matter. The interpretation of stalagmite double laminae, therefore, has considerable potential as a palaeoclimate proxy, and at our study site, we suggest one of severe winters over the last millennium. Copyright © 2002 Royal Meteorological Society.

Palynological analyses in the laminated sediment of Lake Holzmaar (Eifel, Germany): duration of Lateglacial and Preboreal biozones

The laminated sediment of Lake Holzmaar (Germany) has provided a continuous varve chronology for the last 3500 varve years (vy) and beyond that a floating varve chronology back to more than 22500 vy BP. This chronology in calendar years, in combination with palynology, enables us to determine the timing and the magnitude of Lateglacial and Early Holocene environmental changes on land (from 13838 to 10930 vy BP). The palynological diagram has a mean time resolution of 27 vy between samples. This paper establishes for the first time the biozonation for Lake Holzmaar below the Laacher See Tephra. Fifteen pollen subzones grouped in four biozones are defined by cluster analysis. After a period disturbed by microturbidites, only a part of the Bølling is present. Three cold periods have been evidenced by pollen analyses: the Older Dryas (96‐vy‐long), the Younger Dryas (654‐vy‐long) and the Rammelbeek phase (237‐vy‐long). The Allerød (883‐vy‐long) is bipartite with a first Betula‐dominated period followed by a Pinus‐dominated one. The Younger Dryas is also bipartite, with first a decrease of winter temperatures along with a change to a more continental climate. It is followed by a drier phase with a second decrease in temperatures, probably this time also affecting summer temperatures. The Preboreal is 702‐yr‐long. The duration of most phases corresponds to published records, except for that of the Younger Dryas. Cluster and rate‐of‐change analyses indicate a sharp change in the terrestrial vegetation assemblages that may be caused by a sedimentary hiatus of erosive origin during this cold and dry period. As a result, the chronology of Holzmaar has to be revised most likely below the middle of the Younger Dryas. Comparison with the varve record of Meerfelder Maar, a neighbour maar lake, suggests adding 320 vy below 12025 vy.

II. Les parures du Néolithique final à Chalain et Clairvaux

Correlation between nine littoral dwelling sites of the lakes of Chalain and Clairvaux (Jura, France) has allowed to build an almost continuous chronology for the final Neolithic, covering the period from 3200 to 2600 BC. This sequence is checked through dendrochronology : it spans the succession of the Horgen, Clairvaux and Chalain cultures. For this sequence, the study of 484 objects of adornment out of wood, stone, bone, antler and shell was done, in connection with the ceramic evolution and the cultural stimuli formerly recognized. This exceptional series of well dated ornaments allows to show the coming of outside populations in the Combe d'Ain, and in particular small groups coming from the Horgen of Western Switzerland and from the Ferrières of Ardèche, echoing what had been already perceived in the ceramic styles. This series allows also to distinguish phases of stylistical regionalization, as in the case of local manufactures of ornaments, and the reinterpretation of the Ferrières symbols. Further evidences are attained : the evolution of the symbolic of ornaments closely follows rapid changes of the environmental context and of the economy. To an ancient phase (Horgen 3200 BC) where hunting, trophy quest and the use of only slightly modified animal ornaments were prevalent, succeeds a recent one (Clairvaux, 2800 BC) where beads and pendants, made out of stone, were privileged whereas deforested landscape and husbandry take on importance. This striking parallelism between the symbolic data and the environmental context could be explained by social determinisms of general value, those linked to variations in the density of the population and to the impact of man on the forest.

Marianna in Vienna: A Martines Chronology

M arianna never left Vienna, as far as anyone can tell, yet we know almost nothing about her from her birth in that city in 1744, to her death there in 1812. In 1927, a fire in Vienna's Palace of Justice consumed a substantial part of the records of the nobility, but, despite that loss, we can assemble a reasonably continuous chronology of the composer's life in the context of her family. The chronology that follows this discussion is not a biography. It leaves many questions unanswered about the personal and creative life of this excellent composer. Marianna Martines' special situation adds to the difficulties of constructing her biography. It is curious that, so far, not a single word in German has turned up from the hand of this Viennese lady who claimed both German and Italian as her mother tongues.2 We have just eleven letters written by her, and six directed to her by Padre Martini or Farinelli-all in Italian. However, her foster father, the

Historical Principles in Dictionaries of Non-Standardized Vocabularies

HISTORICAL PRINCIPLES IN DICTIONARIES OF NON-STANDARDIZED VOCABULARIES RICHARD A. SPEARS Basing a dictionary on historical material constitutes the technique of dictionary making most widely known and most acceptable to scholars. It is not surprising that the great dictionary project proposed by the Philological Society utilized both the methodology and the findings of historical and comparative philology. Like the Oxford English Dictionary , Craigie's A Dictionary of American English on Historical Principles, and Mathews' A Dictionary of Americanisms on Historical Principles are historically based in that they present numerous citations, but it is not the presence of citations alone that constitutes a historical basis. It is the special goals of the theory or philosophy underlying the use of citations that is central to historical principles. The OED's full title, A New English Dictionary on Historical Principles, suggests that history is used in contrast to other possible orientations, such as an obsession with correctness , a bias toward or against Latin, a bias in selecting citations or entry words, or other practices. The philosophy of lexicography set down by James A. H. Murray in the introduction to the OED provides a rationale for dealing with or containing the need for deterrnining correctness in language . The historical basis is that the history of the use of a word—as evidenced by a chronology of citations—should be the primary evidence for the word's Englishness, sense divisions, form, spelling, and usage. 97 98Richard A. Spears This philosophy covered the standard variety of English almost exclusively and relied on printed citations at a time when standard English dominated the universe ofprinted English . In effect, the data was skewed towards standard English . Despite Murray's assertion that the great dictionary embraced "a large measure of dialectal usage and slang," it contained only a small amount of the slang fisted in Farmer and Henley's Slang and Its Analogs. Similarly, Joseph Wright's English Dialect Dictionary goes far beyond the dialect material found in the OED. The OED philosophy was not tested against slang, jargon, colloquialisms, and other similar vocabulary types. For some, the OED format of printing citations at each entry is equated with historical principles, but the original use of history in a dictionary of standard vocabulary has to do with demonstrating a historical basis for favoring certain senses, spellings, and etymologies of words. Resolving such matters may be important for the standard vocabulary, but it is typically irrelevant for slang, jargon, regionalisms, colloquialisms , argot, dialect, and similar registers. A few illustrative citations do not provide the historical information needed to decide matters of phonological change, morphological change, new senses, expired senses, and all the many other things that are evident in a continuous chronology of quotations. Nonetheless, some people seem satisfied that the use of illustrative quotations constitutes evidence that some type of historical principle has been exercised. Some specialized dictionaries are concerned with types of vocabulary that have been termed slang, jargon, regionalisms , colloquialisms, and the like. These vocabulary types have many casual users, but no usage monitors or exemplary users. Users of these registers may be under social pressure to conform to the rapidly changing social setting of which Historical Principles in Non-Standardized Vocabularies 99 they are a part, but they are not under pressure to conform to a historical, pre-existing, traditional norm. In fact, innovation in these registers is desirable. This contrasts sharply with the pressures in society to use standard English. Standard dictionaries aim at being as complete as possible , while non-standardized dictionaries are totally openended . The absence of an item from a standard dictionary may signify that the item is not a legitimate part of standard English. The absence of a particular item from a slang dictionary , however, says nothing about the item's legitimacy. In these specialized dictionaries, there is no thought that the forms and senses occurring in the printed citations are the only valid forms. Citations for standard dictionaries are gathered by an exhaustive study of printed material. The nonprint sources for a collection of slang, jargon, colloquialisms, or dialect can never be studied exhaustively. Unlike standard English, slang, jargon, regionalisms, colloquialisms , and so forth have no codified or documented standards...

Carbon-14 dates point to man in the Americas 32,000 years ago

The view that man did not arrive on the American continent before the last glaciation has been supported by the fact that until now the known and dated archaeological sites have not been of very great antiquity. But now we report radiocarbon dates from a Brazilian site which establish that early man was living in South America at least 32,000 years ago. These new findings come from the large painted rockshelter of Boqueirao do Sitio da Pedra Furada, the walls and the ceiling of which are decorated with a rich set of prehistoric paintings. We have excavated a sequence containing abundant lithic industry and well-structured hearths at all levels. Carbon-14 dates from charcoal establish a continuous chronology indicating human occupation from 6,160±130 to 32,160±100 years BP. A date of 17,000±400 BP, obtained from charcoal found in a level with fragments of a pictograph fallen from the walls, testifies to the antiquity of rupestral art in this region of Brazil.