Estudio polínico de la turbera del Cueto de la Avellanosa, Polaciones (Cantabria)

[Resumen] El presente trabajo trata del estudio poIínico de una turbera en el Cueto de la Avellanosa, Polaciones (Cantabria). Incluye un diagrama polinico con las especies arbóreas y no arbóreas correspondiente a los 3,4 metros del perfil de la turbera; lo que supone el tratamiento de 34 nuestras de turba que han sido estudiadas desde el punto de vista micropaleontol6gico o paleopolínico. También fueron datadas 3 muestras mediante el 14C. y la edad obtenida xwestra que la turba se formó entre los 6.020 años B.P. y los 1.100 años B.P. El inicio de la turbera se produce durante la transición entre el Boreal y el Atlántico, y tanto estos dos periodos como el Subboreal y Subatlántico aparecen bien definidos en el Palinograma. El conjunto del espectro polinico muestra que la turba se generó bajo condiciones más frias que otros depósitos de turba estudiados en la región Cantábrica o zona Norte.[Abstract] This paper describes the palinological study carried out in a peat deposit in Polaciones (Cantabria, Spain). A 3,4 m profile was obtained and 34 samples were studied. 14C. ages were also determined. The data obtained shows that the peat was formed between 6.020 years B.P. and 1.100 years B.P. starting during the transition between the Boreal and Atlantic, the Subboreal and Subatlantic periods appear well defined in the diagrams. On the whole, the polinic assemblege shows the the peat was formed under colder conditions than other peat deposits studied in the Cantabrian regio

The evolution of the continental and coastal environments during the last climatic cycle in Brazil (120 KY. B.P. to present)

Studies done in Brazil, under the CNPq (Brazil) and ORSTOM (France) agreement, allowed us to envisage the general trend of climatic changes that occurred during the last 60,000 years. At first, examination of successive accumulation and erosion phases, recorded within Central Brazilian valley deposits, provided evidence of importam changes in slope vegetation cover and in the hydraulic regime of water courses, and hence characteristics of precipitation and climate regimes. Studies of Tamanduá river valley deposits in the town of São Simão (State of São Paulo) showed that between 32 and 21 ky. B.P. the climate was humid, whereas between 17 and 11 ky. B.P. it was dry with very scarce and strong rains. From 10 ky to 8.5 ky. B.P. the climate was humid too. Finally, after 7.5 ky. B.P. the deposits revealed the existence of several dry episodes within a globally humid climate. Palynological and sedimentological analyses of lacustrine deposits sampled by vibrocorers in the Eastern Amazon (Carajás, State of Pará) and in Central Brazil (Salitre, State of Minas Gerais) permitted us to outline the evolutionary history of the vegetation cover within these regions during the last 60,000 years for Carajás and 30,000 years for Salitre and thus to have a preliminary idea about their past climates. Then, it was possible to show that at Carajás regression of the evergreen rainforest occurred four times, at about 60, 40, between 23-11 and 7-4 ky. B.P. Moreover, apparently the last rainforest regression episode was quite different from the previous three episodes. At Salitre, the most characteristic is the indication of the existence of Araucária forest between 12 and 8.5 ky. B.P. This Araucária forest location is clearly much further north than at present, which suggests that during that time the climate was wetter and colder. Finally, studies developed along the central Brazilian coast allowed us to show evidence of wind-/driven change in littoral dynamics during the last 5 ky. A detailed examination of Doce river (State of Espírito Santo) mouth beach-ridge geometry has shown inversions in littoral drift direction as a consequence of change in wave and then in wind regimes, reflecting characteristics of atmospheric circulation during the last 5 ky.Estudos feitos no Brasil, segundo um acordo entre o CNPq (Brasil) e ORSTOM (França), permitiram-nos vislumbrar a tendência geral de mudanças climáticas que ocorreram durante os últimos 60.000 anos. Primeiramente, o estudo de sucessivas fases de erosão e sedimentação, registradas nos depósitos de vale do Brasil Central, forneceram evidências de importantes mudanças na cobertura vegetal de vertentes e no regime hidráulico de cursos fluviais e então chegando-se às características dos regimes pluviométricos e climáticos. Estudos de depósitos do vale do rio Tamanduá na cidade de São Simão (SP) mostraram que entre 32 e 21 ka. A.P. o clima foi úmido, enquanto entre 17 e 11 ka. A.P. ele foi seco com chuvas esparsas e fortes. De 10 ka. a 8,5 ka. A.P. o clima foi também úmido. Finalmente, após 7,5 ka. A.P. os depósitos revelaram a existência de vários episódios secos através do clima globalmente úmido. Análises palinológicas e sedimentológicas de depósitos lacustres amostrados por vibrotestemunhador na Amazônia Oriental (Carajás, PA) e no Brasil Central (Salitre, MG) permitiram delinear a história evolutiva da cobertura vegetal nessas regiões, durante os últimos 60.000 anos para Carajás e 30.000 anos para Salitre, e então ter uma idéia preliminar sobre seus paleoclimas. Então foi possível mostrar que em Carajás por quatro vezes, há cerca de 60, 40, entre 23-11 e 7-4 Ka. A.P., ocorreu a regressão da floresta pluvial perene. Além disso, aparentemente o último episódio de regressão da floresta pluvial foi bem diferente dos três episódios anteriores. Em Salitre, mais característica é a indicação da existência de floresta de Araucária entre 12 e 8,5 Ka. A.P. A localização desta floresta de Araucária está claramente mais ao norte que atualmente, sugerindo que durante aquela época o clima era mais úmido e mais frio. Finalmente, estudos desenvolvidos na costa do Brasil Central mostraram evidências de mudanças na dinâmica costeira comandadas pelo vento durante os últimos 5 Ka. Um estudo detalhado da geometria das cristas praiais de desembocadura do rio Doce (ES) mostrou inversões no sentido da deriva litorânea como conseqüência de mudanças nos regimes da onda e do vento, permitindo conhecer as características da circulação atmosférica durante os últimos 5 Ka

Modificación Intencional del Cráneo en San Pedro de Atacama y la Cuenca del Loa: Un Análisis Cuantitativo de su Rol como Marcador de Identidad Social

Diverse hypotheses have been proposed to explain artificial cranial modification (ACM) in South America. In the Atacama area (Northern Chile), some studies have concluded that it was used to create a communal identity that could serve to resist, or to form alliances with, different external groups (Inter Site Distinction hypothesis, this work). On the other hand, other studies have suggested that there was a relationship between ACM and the social status and gender of the individuals within the community (Intra Site Distinction hypothesis, this work). These studies, however, have relied mainly on typological methods and the archaeological contexts to which these modification categories are associated have been simplified as well. In this work we use a quantitative multivariate approach to assess the relationship between cranial morphology and funerary context. The modification patterns of populations inhabiting Northern Chile during the Formative (3500-1600 B.P) and Late Intermediate (950-500 B.P.) periods were studied. We analyzed the X-rays of 203 individuals belonging to 7 archaeological sites and, when possible, they were correlated with the corresponding funerary context. The results indicate that cranial morphology correlates with the interaction networks among sites, therefore these results support the Inter Site hypothesis.Diversas explicaciones han sido propuestas para explicar la modificación intencional del cráneo (ACM) en Sudamérica. En Atacama, algunos estudios han concluido que fue utilizada para crear una identidad común que sirvió para resistir o formar alianzas con distintos grupos foráneos (aquí, Hipótesis de Distinción Inter-Sitio). Otros han sugerido que estaba relacionada con el estatus social y/o el sexo de los individuos dentro de la comunidad (aquí, Hipótesis de Distinción Intra-Sitio). Sin embargo, los métodos usados para llegar a estas conclusiones tienen limitaciones significativas porque han usado principalmente métodos tipológicos y los contextos arqueológicos a los que han sido asociados estas categorías de ACM han sido simplificados. Aquí usamos un enfoque multivariado y cuantitativo para evaluar la relación entre la morfología craneal y el contexto funerario. Se analizó la ACM de las poblaciones que habitaron el Norte de Chile durante el Periodo Formativo (3500-1600 B.P) y el Periodo Intermedio Tardío (950-500 B.P.). Se analizaron los rayos X de 203 individuos pertenecientes de 7 sitios arqueológicos y, cuando fue posible, estos fueron correlacionados con su contexto funerario. Los resultados indican que la morfología craneal se correlaciona con las redes de intercambio entre los sitios. Estos resultados apoyan la Hipótesis de Distinción Intra-Sitio

A factor analysis approch to measuring European loan and bond market integration

By using an existing and a new convergence measure, this paper assesses whether bank loan and bond interest rates are converging for the non-financial corporate sector across the euro area. Whilst we find evidence for complete bond market integration, the market for bank loans remains segmented, albeit to various degrees depending on the type and size of the loan. Factor analysis reveals that rates on large loans and small loans with long rate fixation periods have weakly converged in the sense that, up to a fixed effect, their evolution is driven by common factors only. In contrast, the price evolution of small loans with short rate fixation periods is still affected by country-specific dynamic factors. There are few signs that bank loan rates are becoming more uniform with time

Aportación al conocimiento paleoecológico del Holoceno en el NW de la Península Ibérica

Se ha hecho análisis polínico de dos palcosudos enterrados bajo un yacimiento arqueológico de cultura catrexa y dt un depósito lacustre. Los tres está.n geográficamente próximos y son com:lacionablc.~ debido a la CXJSI-encia d!:.datacioncs C-14 y a datos culturales. Coll los datos polfnicos obtenidos, se ban hecho dos diagramas en los que se dcfmcn distintas etapas de vegetación dc5dc finales del Sub-Boreal al Sub-Atlántico actual. Dichas etapas son: fin Uel Sub-Boreal con boS()UC de Q¡:e~eu.r y presencia de ÚlJianea; expansión del roble a comien- 7.0s del Sub-Atlántico y presencia deAinus; fase de cultivo de COJtanta hacia 1580 B.P .; fase de máxima dcforcsucióo y fmalmcntc, fase. de cultivo dcPjnr.uA polleo analysi! of two palcosoih buricd under an arcbacological deposit o[ caHcxa culture aod Jakc dcposils was carricd out. Thc thrcc are geograpbkally close and are relatcd as tbe cOOstence of C-14 data and cultaral in(onnation preves. With the po11en data oblai.ned we dcvi.sed rwo diagrams dcfming severa! Mage..~ of vegc.tation ranging from thc cnd of lhc Sub-Boreal te thc prcscnt Sub·Atlantic. Thcse stagcs are: tbc cnd of tbc Sub-Boreal wi tb QuerroJ furcsts and thc prcsc:mx: of Ca¡ftm , u; extcrmon o( oaks at thc bcginning of thc Sub-Atlantic and the presence of Afnus; tbe Castnnea cultivation phase (rom about 1580 B.P .; the maximum deforcslation phase and lastly, cultivation ofthe Pil11tS phas

Late Holocene palynology and palaeovegetation of tephra-bearing mires at Papamoa and Waihi Beach, western Bay of Plenty, North Island, New Zealand.

The vegetation history of two mires associated with Holocene dunes near the western Bay of Plenty coast, North Island, New Zealand, is deduced from pollen analysis of two cores. Correlation of airfall tephra layers in the peats, and radiocarbon dates, indicate that the mires at Papamoa and Waihi Beach are c. 4600 and c. 2900 conventional radiocarbon years old, respectively. Tephras used to constrain the chronology of the pollen record include Rotomahana (1886 AD), Kaharoa (700 yr B.P.), Taupo (Unit Y; 1850 yr B.P.), Whakaipo (Unit V; 2700 yr B.P.), Stent (Unit Q; 4000 yr B.P.), Hinemaiaia (Unit K; 4600 yr B.P.), and reworked Whakatane (c. 4800 yr B.P.) at Papamoa, and Kaharoa and Taupo at Waihi Beach. Peat accumulation rates at Papamoa from 4600 - 1850 yr B.P. range from 0.94 to 2.64 mm/yr (mean 1.37 mm/yr). At Waihi Beach, from 2900 yr B.P. - present day, they range from 0.11 to 0.21 mm/yr (mean 0.20 mm/yr). Peat accumulation at both sites was slowest from 1850 to 700 yr B.P., suggesting a drier overall climate during this interval. At both sites, the earliest organic sediments, which are underlain by marine or estuarine sands, yield pollen spectra indicating salt marsh or estuarine environments. Coastal vegetation communities declined at both sites, as sea level gradually fell or the coast prograded, and were eventually superseded by a low moor bog at Papamoa, and a mesotrophic swamp forest at Waihi Beach. These differences, and the marked variation in peat accumulation rates, probably reflect local hydrology and are unlikely to have been climatically controlled. The main regional vegetation during this period was mixed northern conifer-angiosperm forest. Kauri (Agathis australis) formed a minor component of these forests, but populations of this tree have apparently not expanded during the late Holocene at these sites, which are near its present southern limit. Occasional shortlived forest disturbances are detectable in these records, in particular immediately following the deposition of Taupo Tephra. However, evidence for forest clearance during the human era is blurred by the downward dislocation of modern adventi ve pollen at these sites, preventing the clear differentiation of the Polynesian and European eras

Stratigraphy and chronology of the Stent tephra, a c. 4000 year old distal silicic tephra from Taupo Volcanic Centre, New Zealand.

Tephrostratigraphic and chronologic studies in two areas of the North Island have identified a previously unrecorded, thin, distal silicic tephra derived from the Taupo Volcanic Centre. In Taranaki, three radiocarbon ages of the uncorrelated tephra are consistent with the independent radiocarbon chronology obtained from enveloping Egmontsourced tephras. In western Bay of Plenty, where the uncorrelated tephra is also directly dated, it is overlain by Whakaipo Tephra (c. 2.7 ka) and underlain by Hinemaiaia Tephra (c. 4.5 ka). From these sites in Taranaki and western Bay of Plenty, seven radiocarbon dates obtained on the uncorrelated silicic tephra yield an error-weighted mean age of 3970 ±31 conventional radiocarbon years B.P. The ages on the uncorrelated tephra (informally referred to as Stent tephra) from both areas are statistically identical but significantly different from those on both Waimihia and Hinemaiaia Tephras. occurrence of Stent tephra in Taranaki, c. 160 km upwind from the postulated source area, and in western Bay of Plenty, suggests that it represents the product of a moderately large plinian eruption. Until recently, its validity as a discrete eruptive event had been problematical, because a near-source equivalent deposit between Waimihia and Hinemaiaia Tephras was not recognised in the Taupo area. However, a revised stratigraphy proposed by C. J. N. Wilson in 1993 for eastern sectors of the Taupo area shows that multiple tephra layers were erupted from Taupo volcano between c. 3.9 and 5.2 ka. Of these newly recognised layers, unit-g--the product of a moderately large eruption (>0.15 km3) at c. 4.0 ka--is tentatively correlated with Stent tephra. Other eruptive units recognised by Wilson are either too old or too small in volume to be considered as likely correlatives

Uncertainties and shortcomings of ground surface temperature histories derived from inversion of temperature logs

Analysing borehole temperature data in terms of ground surface history can add useful information to reconstructions of past climates. Therefore, a rigorous assessment of uncertainties and error sources is a necessary prerequisite for the meaningful interpretation of such ground surface temperature histories. This study analyses the most prominent sources of uncertainty. The diffusive nature of the process makes the inversion relatively robust against incomplete knowledge of the thermal diffusivity. Similarly the influence of heat production is small. It turns out that for investigations of the last 1000 to 100000 years the maximum depth of the temperature log is crucial. More than 3000 m are required for an optimal inversion. Reconstructions of the last one or two millennia require only modestly deep logs (>300 m) but suffer severely from noisy data.Comment: 28 pages, 18 figure, 3 table

Regression trend lines of ridges and swales on the emergent beach at Gisborne, New Zealand

The emergent sand-beach system at Gisborne consists of six recognisable groups of ridges and swales. It is about three miles wide and four miles long and rises gradually from 15ft above sea level at the coast to 40ft inland. From time to time the emergent beach has been mantled with air-borne volcanic ash including ash beds of the Waimihia Lapilli, Taupo Sub-group Members 9 - 13, Taupo Pumice, and Kaharoa Ash Formations. As the dates of these eruptions are known, the times of formation of the groups of beach ridges and wales have been determined as follows: Group 1: c. 9000 B.C. - c. 1400 B.C. Group 2: c. 1400 B.C. - (?) 850 B.C. Group 3: (?) 850 B.C. - c. A.D. 131 Group 4: c. A.D. 131 - c. A.D. 1020 Group 5: c. A.D. 1020 - c. A.D. 1650 Group 6: c. A.D. 1650 - A.D. 1956 Evidence of recent earth movements has been noted in ridges and swales of Group 1, and of possible movements in those of Group 3. Changes in sea level could not be established and were taken from Wellman and Schofield. No attempt was made to distinguish directly wind-blown sand from wave-deposited sand; instead, a shell layer (assumed to be associated with the intertidal strand) was used as a marker bed to indicate the approximate sea level at the time when the shells were deposited. Elevations of ridges and swales in each group were measured on a 15,000ft transect across the beach system. Then, overall linear and quadratic regressions as well as linear regressions for each group separately were computed. For both of the overall linear and quadratic regressions the trend lines show a fall seaward, but the separate trend lines for each group are as follows: Group 1: Highly significant seaward decline. Groups 2 and 3 combined: Very highly significant seaward decline. Group 4: Highly significant seaward incline. Groups 5 and 6 combined: No significant change. The departure of the regression trend lines within Groups 1 to 6 from the overall linear and quadratic trend lines suggests that the trends of elevation across the emergent beach at Gisborne should be regarded more as a series of discontinuous trends rather than as one overall continuous trend of seaward decline. Though the overall trend of declining elevation is seaward, the corresponding fall in sea level is likely to be more apparent than real because of compounding of fall in sea level with earth movements