Paleoenvironmental analysis of wet meadow in the Deseado Massif: Implications for the Holocene occupation of Argentinian Patagonia

The Holocene ◽  
2021 ◽  
pp. 095968362110259
Author(s):  
Bruno Mosquera ◽  
María V Mancini
Keyword(s):  
Environmental Changes ◽  
Low Energy ◽  
Semiarid Region ◽  
Human Occupation ◽  
Wet Meadow ◽  
Radiocarbon Dates ◽  
Sedimentation Environment ◽  
Dry Conditions ◽  
Paleoenvironmental Analysis ◽  
Deseado Massif

Paleoenvironmental data from wet-meadow environments in the arid-semiarid region of Patagonia are still incipient and the paleoenvironmental records came from pollen sequences of caves and rockshelters. The main reasons to study wetland records are their undisturbed (by humans) sedimentologic continuity, in contrast to deposits in rock shelters and caves; and their regional presentation of environmental changes that can be compared to archeological data. The aim of this paper is to evaluate the past hydrological dynamic of a wet-meadow from Deseado Massif and its relationship with the human occupation. For this purpose, we present the results of the sediment and pollen analysis of Mallín La Primavera wet-meadow that provide a sequence starting in the mid-Holocene. The results indicate a lower water table in the mallín prior to 6900 cal yr BP. Sediment analysis indicates low energy sedimentation environment with flood events and very low energy streams. Human occupational data show chronological discontinuities in mid-Holocene in several regions of Patagonia and the southern cone. In the studied region, two chronological hiatuses (7828–6434 cal yr BP and 3005–2710 cal yr BP) where recognized that appear to correlate with shrub steppes, indicating dry conditions. These conditions may explain the lack of archeological radiocarbon dates in the area during this period. The integration of sediment and pollen results from the Deseado Massif indicates dry and windy conditions for the middle Holocene. The lack of archeological radiocarbon dates would have been influenced by the loss of moisture in water sources such as springs and their associated wet meadows ( mallines).

Paleoenvironmental interpretation of the paleosols and sediments at the Stampede site (DjOn-26), Cypress Hills, Alberta

2004 ◽  
Vol 41 (6) ◽  
pp. 741-753 ◽  
Author(s):  
Judith Klassen
Keyword(s):  
Stable Carbon Isotopes ◽  
Archaeological Site ◽  
Time Interval ◽  
Accumulation Rates ◽  
Human Occupation ◽  
High Accumulation ◽  
Radiocarbon Dates ◽  
Dry Conditions ◽  
Paleoenvironmental Interpretation ◽  
Ancient Site

A 3.65 m-thick sequence of paleosols and sediments exposed at the Stampede archaeological site provides an opportunity for studying climate change and its impact on ancient site utilization over a 7200-year period. Three radiocarbon dates establish temporal boundaries for the lower sequence of paleosols and sediments at 7200 and 6100 BP. This lower sequence is characterized by lack of cultural material in most paleosols, high accumulation rates, and evidence for fluvial deposition. The upper sequence dates from 6100 BP and is characterized by low accumulation rates, increased pedogenesis, and increased evidence for human occupation, particularily between 4660 and 5230 BP. Phytoliths provide a strong signal for grassland vegetation beginning at 6100 years BP coincident with the most intensive occupation of the site. Stable carbon isotopes and carbon/nitrogen (C/N) ratios support the presence of grass. The differences evident between the lower and upper sequences can be attributed to the change from warm dry conditions to cooler, moister conditions and agree to a first approximation with the information inferred from the nearby Elkwater Lake and Harris Lake records. However, the persistence of forest at the Stampede site for a 1400-year time interval, when the Harris Lake record indicates more arid conditions, suggests that springs and north-facing slopes made the Cypress Hills an "oasis" for both animals and people.

Paleoclimatic and archeological implications of Pleistocene and Holocene environments in Azraq, Jordan

2011 ◽  
Vol 76 (3) ◽  
pp. 363-372 ◽  
Author(s):  
Matthew D. Jones ◽  
Tobias Richter
Keyword(s):  
Environmental Changes ◽  
Eastern Mediterranean ◽  
Human Occupation ◽  
Last Glacial ◽  
The North ◽  
Time Period ◽  
Dry Conditions ◽  
Archeological Evidence ◽  
Climatic Transition ◽  
The Last Glacial

AbstractWetlands are a key archive for paleoclimatic and archeological work, particularly in arid regions, as they provide a focus for human occupation and preserve environmental information. The sedimentary record from 'Ayn Qasiyya, a spring site on the edge of the Azraq Qa, provides a well-dated sequence through the last glacial–interglacial transition (LGIT) allowing environmental changes in the present-day Jordanian desert to be investigated robustly through this time period for the first time. Results show that the wettest period at the site preceded the last glacial maximum, which itself was characterised by marsh formation and a significant Early Epipaleolithic occupation. A sedimentary hiatus between 16 and 10.5 ka suggests a period of drought in the region although seasonal rains and surface waters still allowed seasonal occupation of the Azraq region. Archeological evidence suggests that conditions had improved by the Late Epipaleolithic, about the time of the North Atlantic Younger Dryas. The changes between wet and dry conditions at the site show similarities to patterns in the eastern Mediterranean and in Arabia suggesting the Jordan interior was influenced by changes in both these regions through the LGIT climatic transition.

scholarly journals Debris Flows Occurrence in the Semiarid Central Andes under Climate Change Scenario

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 43
Author(s):  
Stella M. Moreiras ◽  
Sergio A. Sepúlveda ◽  
Mariana Correas-González ◽  
Carolina Lauro ◽  
Iván Vergara ◽  
...  
Keyword(s):  
Climate Change ◽  
Debris Flows ◽  
Environmental Changes ◽  
Urban Expansion ◽  
Central Andes ◽  
Semiarid Region ◽  
Change Scenario ◽  
Permafrost Degradation ◽  
Mountain Areas ◽  
Negative Impacts

This review paper compiles research related to debris flows and hyperconcentrated flows in the central Andes (30°–33° S), updating the knowledge of these phenomena in this semiarid region. Continuous records of these phenomena are lacking through the Andean region; intense precipitations, sudden snowmelt, increased temperatures on high relief mountain areas, and permafrost degradation are related to violent flow discharges. Documented catastrophic consequences related to these geoclimatic events highlight the need to improve their understanding in order to prepare the Andean communities for this latent danger. An amplified impact is expected not only due to environmental changes potentially linked to climate change but also due to rising exposure linked to urban expansion toward more susceptible or unstable areas. This review highlights as well the need for the implementation of preventive measures to reduce the negative impacts and vulnerability of the Andean communities in the global warming context.

scholarly journals A high-altitude peatland record of environmental changes in the NW Argentine Andes (24 ° S) over the last 2100 years

2016 ◽  
Vol 12 (5) ◽  
pp. 1165-1180 ◽  
Author(s):  
Karsten Schittek ◽  
Sebastian T. Kock ◽  
Andreas Lücke ◽  
Jonathan Hense ◽  
Christian Ohlendorf ◽  
...  
Keyword(s):  
High Altitude ◽  
Environmental Changes ◽  
Regional Scale ◽  
Central Andes ◽  
High Accumulation ◽  
Climate Conditions ◽  
Climate Anomalies ◽  
Dry Conditions ◽  
Induced Changes ◽  
The 19Th Century

Abstract. High-altitude cushion peatlands are versatile archives for high-resolution palaeoenvironmental studies, due to their high accumulation rates, range of proxies, and sensitivity to climatic and/or human-induced changes. Especially within the Central Andes, the knowledge about climate conditions during the Holocene is limited. In this study, we present the environmental and climatic history for the last 2100 years of Cerro Tuzgle peatland (CTP), located in the dry Puna of NW Argentina, based on a multi-proxy approach. X-ray fluorescence (XRF), stable isotope and element content analyses (δ13C, δ15N, TN and TOC) were conducted to analyse the inorganic geochemistry throughout the sequence, revealing changes in the peatlands' past redox conditions. Pollen assemblages give an insight into substantial environmental changes on a regional scale. The palaeoclimate varied significantly during the last 2100 years. The results reflect prominent late Holocene climate anomalies and provide evidence that in situ moisture changes were coupled to the migration of the Intertropical Convergence Zone (ITCZ). A period of sustained dry conditions prevailed from around 150 BC to around AD 150. A more humid phase dominated between AD 200 and AD 550. Afterwards, the climate was characterised by changes between drier and wetter conditions, with droughts at around AD 650–800 and AD  1000–1100. Volcanic forcing at the beginning of the 19th century (1815 Tambora eruption) seems to have had an impact on climatic settings in the Central Andes. In the past, the peatland recovered from climatic perturbations. Today, CTP is heavily degraded by human interventions, and the peat deposit is becoming increasingly susceptible to erosion and incision.

scholarly journals RONA LINGKUNGAN GEOLOGI KELAUTAN DI PERAIRAN P. ROTE NUSA TENGGARA TIMUR

2016 ◽  
Vol 11 (3) ◽  
pp. 149
Author(s):  
Yudi Darlan ◽  
Udaya Kamiludin
Keyword(s):  
Environmental Changes ◽  
Good Condition ◽  
High Energy ◽  
Surficial Sediment ◽  
Silty Sand ◽  
Sedimentation Environment ◽  
Standard Quality ◽  
Marine Environmental ◽  
Base Data

Sejalan dengan perubahan Pulau Rote dari Pemerintahan Kecamatan menjadi Kabupaten, pembangunan infrastruktur pesisir dan sektor lainnya di pulau ini meningkat. Pembangunan tersebut dari tahun ke tahun dapat menimbulkan perubahan kondisi lingkungan pesisir dan perairan Pulau Rote. Perubahan kondisi lingkungan dapat diidentifikasi melalui analisis data rona lingkungan. Data seismik memperlihatkan morfologi teras-teras pantai, dan intrusi diapir serpih di perairan Pulau Rote yang mengiindikasikan pulau ini mengalami proses pengangkatan sejak ribuan tahun yang lalu hingga sekarang. Sedimen permukaan dasar laut Pulau Rote terdiri atas pasir dan pasir lanauan mengandung mineral kuarsa, piroksen, mineral karbonatan dan cangkang moluska menunjukkan kondisi lingkungan sedimentasi rendah. Baku Mutu air dan sedimen permukaan dasar laut di perairan Pulau Rote dalam kondisi baik. Jenis pantainya berupa pantai berenergi tinggi, pantai erosi, pantai teluk, dan pantai kantong pasir masih dalam kondisi baik dan cukup bagus bagi wisata pantai dan laut. Hasil penelitian ini menunjukkan sebagain besar kondisi lingkungan perairan Pulau Rote masih dalam kondisi baik. Sebagian kecil ada perubahan sebagai dampak aktivitas manusia. Kata kunci: rona lingkungan, geologi kelautan, intrusi, diapir serpih, Nusa Tenggara Timur, Pulau Rote Since the Rote Island government changed from the Kecamatan to Kabupaten Government, the development of coastal infrastructures and other sectors in the island increased. The development from time to time can lead to changes in coastal and marine environmental of the Rote Island. The environmental conditions can be identified through analysis environmental base data. The seismic data shows the morphology of coastal terraces, and intrusion of shale diapir in the Rote Island waters which indicate that this island has uplifted since thousands years ago until now. Surficial sediment of the Rote Island waters consists of sand and silty sand containing quartz and pyroxene minerals, and shells of mollusks which indicate low sedimentation environment. The standard quality of surface water and surficial sediment of the Rote Island is still in good condition. Coastal characteristics of this island consist of high-energy beaches, sand pocket beaches, bays, and erosion coasts which are still in good condition and suitable for tourism. This study shows that in general the environment of the Rote Island waters environment is normal conditions. A few of environmental changes is as an impact of human activities. Keywords: environment features, intrusion, shale diapir, Nusa Tenggara Timur, Rote island.

scholarly journals Pampean lizard assemblage from subtropical Brazil: a temporal analysis

2011 ◽  
Vol 83 (4) ◽  
pp. 1345-1358 ◽  
Author(s):  
Gisele R. Winck ◽  
Tiago G. Dos Santos ◽  
Sonia Z. Cechin
Keyword(s):  
Environmental Changes ◽  
Seasonal Pattern ◽  
Natural Populations ◽  
Temporal Analysis ◽  
Natural Environments ◽  
Human Occupation ◽  
Environmental Disturbances ◽  
Pampa Biome ◽  
History Of ◽  
Recruitment Period

The increasing human occupation of natural environments is one of the greatest threats to biodiversity. To mitigate the negative anthropogenic effects, it is necessary to understand the characteristics of natural populations and the natural history of species. A study was conducted with an assemblage of lizards from a disturbed area of the Pampa biome, from February 2001 to January 2004. The assemblage showed a unimodal seasonal pattern, with the recruitment period occurring during the warmer months. The captures were seasonal for two of the three monitored years, and concentrated within warmer months. The minimum temperature explained the number of catches for the assemblage as a whole. However, when the species were analyzed individually, the temperature only explained the seasonal occurrence of Teius oculatus. The abundance of species was significantly different in the third year of study for Cercosaura schreibersii and Ophiodes striatus. This latter species was no longer registered in the study area from May 2003 until the end of the study. Therefore, O. striatus may be more sensitive to environmental changes, considering the events of change in vegetation during the study. With frequent and increasing environmental disturbances, it is necessary to take conservation measures and encourage the increase of knowledge on Pampean lizards.

scholarly journals MONITORAMENTO DA COBERTURA VEGETAL POR SENSORIAMENTO REMOTO NO SEMIÁRIDO BRASILEIRO ATRAVÉS DE ÍNDICES DE VEGETAÇÃO

Nativa ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 708
Author(s):  
Caio Victor Santos Silva ◽  
Jhon Lennon Bezerra da Silva ◽  
Geber Barbosa De Albuquerque Moura ◽  
Pabrício Marcos Oliveira Lopes ◽  
Cristina Rodrigues Nascimento ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Vegetation Cover ◽  
Environmental Changes ◽  
Spectral Response ◽  
Vegetation Indices ◽  
Digital Processing ◽  
Semiarid Region ◽  
Dry Period ◽  
Biophysical Parameters ◽  
Brazilian Semiarid

São necessárias medidas que visem à proteção e conservação dos recursos hídricos e naturais de forma rápida e eficiente. As técnicas de sensoriamento remoto são essenciais para o monitoramento ambiental dos recursos no semiárido no espaço e no tempo. Objetivou-se monitorar e analisar à dinâmica da cobertura vegetal através da variabilidade espaço-temporal do albedo da superfície e índices de vegetação em região de Caatinga do semiárido brasileiro por sensoriamento remoto. A área de estudo é o município de Arcoverde, localizado no semiárido de Pernambuco. O estudo foi desenvolvido através de seis imagens orbitais do Landsat-5 do sensor TM. O processamento digital dos parâmetros biofísicos foi realizado pelo algoritmo SEBAL. Os resultados foram analisados através da estatística descritiva e quanto a sua variabilidade. Áreas possivelmente degradadas foram identificadas pelos altos valores de albedo e índices de vegetação significativamente menores, localizadas à sudoeste e noroeste da região. Os índices apresentaram comportamento similares, principalmente no período seco, com baixos valores sendo próximos de zero, áreas afetadas pelo período de seca no semiárido. O SAVI apresentou maior precisão, destacando melhor resposta espectral da vegetação. O sensoriamento remoto promoveu monitoramento espaço-temporal adequado, destacando principalmente o período classificado como climaticamente seco através do albedo e índices de vegetação.Palavras-chave: Caatinga; NDVI; SAVI; mudanças ambientais; SEBAL. MONITORING OF VEGETATION COVER BY REMOTE SENSING IN BRAZILIAN SEMIARID THROUGH VEGETATION INDICES ABSTRACT: Measures are needed aimed at the protection and conservation of water and natural resources quickly and efficiently. Remote sensing techniques are essential for the environmental monitoring of resources in the semiarid region in space and time. Aimed to monitor and analyze the dynamics of vegetation cover through the spatial-temporal variability of the surface albedo and indices of vegetation in the Caatinga region of the Brazilian semiarid by remote sensing. The study area is the municipality of Arcoverde, located in the semiarid of Pernambuco. The study was developed through six orbital images of Landsat-5 of the TM sensor. The digital processing of the biophysical parameters was performed by the SEBAL algorithm. The results were analyzed through descriptive statistics and their variability. Possibly degraded areas were identified by high albedo values and significantly lower vegetation indices, located in the southwest and northwest of the region. The indexes showed similar behavior, mainly in the dry period, with low values being close to zero, areas affected by the dry period in the semiarid. The SAVI presented higher accuracy, highlighting better spectral response of the vegetation. Remote sensing promoted adequate space-time monitoring, highlighting mainly the period classified as climatically dry through the albedo and vegetation indexes.Keywords: Caatinga; NDVI; SAVI; environmental changes; SEBAL.

NEW RADIOCARBON DATES FROM ARCHAEOLOGICAL SITES IN PARTS OF IGBOLAND, SOUTHEASTERN NIGERIA

Radiocarbon ◽  
2022 ◽  
pp. 1-16
Author(s):  
Kenechukwu Chidiogo Daniel ◽  
Anselm Maduabuchi Ibeanu ◽  
Jacinta Uchenna Ikegwu ◽  
Emuobosa Akpo Orijemie
Keyword(s):  
Archaeological Sites ◽  
Human Settlement ◽  
Human Occupation ◽  
Southeastern Nigeria ◽  
Radiocarbon Dates ◽  
Iron Smelting ◽  
Subsistence Patterns ◽  
Early Human

ABSTRACT This paper presents new results of radiocarbon (14C) ages from archaeological sites in northern Igboland. The study was designed to shed more light on early human occupation and activities in the study area based on sediments from cave and iron-smelting sites. The approach consisted of ethnographic, archaeological, palynological, and slag analyses; these were complemented with 14C dates. The technology adopted as well as the paleoenvironmental conditions that prevailed during the period of human settlement in both sites was revealed. These data, complemented by 14C dates, highlight the human behavioral and subsistence patterns within the region and are comparable to those from similar sites in southeastern Nigeria.

scholarly journals Maternal effect determines drought resistance of eggs in the predatory mite Phytoseiulus persimilis

Oecologia ◽  
2019 ◽  
Vol 192 (1) ◽  
pp. 29-41 ◽  
Author(s):  
Sophie Le Hesran ◽  
Thomas Groot ◽  
Markus Knapp ◽  
Tibor Bukovinszky ◽  
Jovano Erris Nugroho ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Maternal Effect ◽  
Environmental Changes ◽  
Biological Control Agent ◽  
Phytoseiulus Persimilis ◽  
Predatory Mite ◽  
Control Agent ◽  
Hatching Rate ◽  
Dry Conditions ◽  
Low Humidity

AbstractThe ability of an organism to adapt to short-term environmental changes within its lifetime is of fundamental importance. This adaptation may occur through phenotypic plasticity. Insects and mites, in particular, are sensitive to changes in temperature and humidity, especially during the juvenile stages. We studied the role of phenotypic plasticity in the adaptation of eggs to different relative humidity conditions, in the predatory mite Phytoseiulus persimilis, used worldwide as a biological control agent of the spider mite Tetranychus urticae. The biocontrol efficacy of P. persimilis decreases under dry conditions, partly because P. persimilis eggs are sensitive to drought. We exposed P. persimilis adult females from two different strains to constant and variable humidity regimes and evaluated the hatching rate of their eggs in dry conditions, as well as the survival and oviposition rates of these females. Whereas the eggs laid by P. persimilis females exposed to constant high humidity did not survive in dry conditions, females exposed to constant low humidity started laying drought-resistant eggs after 24 h of exposure. Survival and oviposition rates of the females were affected by humidity: females laid fewer eggs under constant low humidity and had a shorter lifespan under constant high and constant low humidity. The humidity regimes tested had similar effects across the two P. persimilis strains. Our results demonstrate that transgenerational phenotypic plasticity, called maternal effect, allows P. persimilis females to prepare their offspring for dry conditions.

scholarly journals Tree-Ring Records of Near-Younger Dryas Time in Central North America—Preliminary Results from the Lincoln Quarry Site, Central Illinois, Usa

Radiocarbon ◽  
2004 ◽  
Vol 46 (2) ◽  
pp. 933-941 ◽  
Author(s):  
Irina P Panyushkina ◽  
Steven W Leavitt ◽  
Alex Wiedenhoeft ◽  
Sarah Noggle ◽  
Brandon Curry ◽  
...  
Keyword(s):  
North America ◽  
Tree Ring ◽  
Environmental Changes ◽  
Ring Width ◽  
Younger Dryas ◽  
Late Glacial ◽  
Radiocarbon Dates ◽  
Initial Sampling ◽  
Central Illinois ◽  
A Site

The abrupt millennial-scale changes associated with the Younger Dryas (YD) event (“chronozone”) near the dawn of the Holocene are at least hemispheric, if not global, in extent. Evidence for the YD cold excursion is abundant in Europe but fairly meager in central North America. We are engaged in an investigation of high-resolution environmental changes in mid-North America over several millennia (about 10,000 to 14,000 BP) during the Late Glacial–Early Holocene transition, including the YD interval. Several sites containing logs or stumps have been identified and we are in the process of initial sampling or re-sampling them for this project. Here, we report on a site in central Illinois containing a deposit of logs initially thought to be of YD age preserved in alluvial sands. The assemblage of wood represents hardwood (angiosperm) trees, and the ring-width characteristics are favorable to developing formal tree-ring chronologies. However, 4 new radiocarbon dates indicate deposition of wood may have taken place over at least 8000 14C yr (6000–14,000 BP). This complicates the effort to develop a single floating chronology of several hundred years at this site, but it may provide wood from a restricted region over a long period of time from which to develop a sequence of floating chronologies, the timing of deposition and preservation of which could be related to paleoclimatic events and conditions.

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