Problems of Developing the Pleistocene Radiocarbon Chronology within high Mountain Terranes by the Example of Russian Altai

Radiocarbon ◽  
2019 ◽  
Vol 61 (6) ◽  
pp. 2019-2028 ◽  
Author(s):  
Anna Agatova ◽  
Roman Nepop ◽  
Elya Zazovskaya ◽  
Ivan Ovchinnikov ◽  
Piotr Moska
Keyword(s):  
Organic Material ◽  
High Mountain ◽  
Proxy Data ◽  
Near Surface ◽  
Treatment Techniques ◽  
Tectonically Active ◽  
Dating Method ◽  
Pre Treatment ◽  
Radiocarbon Chronology ◽  
Russian Altai

ABSTRACTThe paper presents a discussion of 24 radiocarbon (14C) dates of organic material from deposits of various genesis within the intermountain depressions and valleys of the Russian Altai. These apparent 14C ages (sometimes near the upper time limit of the 14C dating method) contradict to other proxy data and optically stimulated luminescence (OSL) dates. Rejuvenation of ancient deposits by 14C dating encountered two problems: (1) wrong interpretation of previously unknown near-surface location of Tertiary deposits as being of the Pleistocene ones with the redeposited ancient flora; and (2) wrong age estimation of the Pleistocene-Holocene deposits with redeposited Carboniferous, Jurassic, and Neogene organic material, which is represented as inclusions. Significant scattering of 14C ages, their inversion within a section, and discrepancy with other proxy data indicate penetrating of the “young” carbon into ancient organic material, and its presence in a unique (for each sample) ratio. Today such contamination cannot be eliminated utilizing standard pre-treatment techniques. The influx of “young” carbon is related to post-sedimentation tectonic and exogenous processes, which are common for tectonically active mountain provinces including Altai. The reported problem is not a new one, although methodological studies in the Russian Altai have not yet been carried out earlier.

scholarly journals Local radon flux maxima in the quaternary sediments of Schleswig–Holstein (Germany)

2021 ◽  
Author(s):  
Johannes Albert ◽  
Maximilian Schärf ◽  
Frieder Enzmann ◽  
Martin Waltl ◽  
Frank Sirocko
Keyword(s):  
Water Content ◽  
Pore Space ◽  
Mineralogical Composition ◽  
Fault System ◽  
Near Surface ◽  
Salt Diapirism ◽  
The North ◽  
Radon Flux ◽  
Published Evidence ◽  
Tectonically Active

AbstractThis paper presents radon flux profiles from four regions in Schleswig–Holstein (Northern Germany). Three of these regions are located over deep-rooted tectonic faults or salt diapirs and one is in an area without any tectonic or halokinetic activity, but with steep topography. Contrary to recently published studies on spatial patterns of soil radon gas concentration we measured flux of radon from soil into the atmosphere. All radon devices of each profile were deployed simultaneously to avoid inconsistencies due to strong diurnal variations of radon exhalation. To compare data from different seasons, values had to be normalized. Observed radon flux patterns are apparently related to the mineralogical composition of the Quaternary strata (particularly to the abundance of reddish granite and porphyry), and its grain size (with a flux maximum in well-sorted sand/silt). Minimum radon flux occurs above non-permeable, clay-rich soil layers. Small amounts of water content in the pore space increase radon flux, whereas excessive water content lessens it. Peak flux values, however, are observed over a deep-rooted fault system on the eastern side of Lake Plön, i.e., at the boundary of the Eastholstein Platform and the Eastholstein Trough. Furthermore, high radon flux values are observed in two regions associated with salt diapirism and near-surface halokinetic faults. These regions show frequent local radon flux maxima, which indicate that the uppermost strata above salt diapirs are very inhomogeneous. Deep-rooted increased permeability (effective radon flux depth) or just the boundaries between permeable and impermeable strata appear to concentrate radon flux. In summary, our radon flux profiles are in accordance with the published evidence of low radon concentrations in the “normal” soils of Schleswig–Holstein. However, very high values of radon flux are likely to occur at distinct locations near salt diapirism at depth, boundaries between permeable and impermeable strata, and finally at the tectonically active flanks of the North German Basin.

Climate change in the High Mountain Asia simulated with CMIP6 models

2021 ◽  
Author(s):  
Mickaël Lalande ◽  
Martin Ménégoz ◽  
Gerhard Krinner
Keyword(s):  
High Resolution ◽  
Snow Cover ◽  
Climate Models ◽  
Global Climate Models ◽  
Cold Bias ◽  
High Mountain ◽  
The Tibetan Plateau ◽  
Near Surface ◽  
Model Biases ◽  
Snow Cover Extent

<p>The High Mountains of Asia (HMA) region and the Tibetan Plateau (TP), with an average altitude of 4000 m, are hosting the third largest reservoir of glaciers and snow after the two polar ice caps, and are at the origin of strong orographic precipitation. Climate studies over HMA are related to serious challenges concerning the exposure of human infrastructures to natural hazards and the water resources for agriculture, drinking water, and hydroelectricity to whom several hundred million inhabitants of the Indian subcontinent are depending. However, climate variables such as temperature, precipitation, and snow cover are poorly described by global climate models because their coarse resolution is not adapted to the rugged topography of this region. Since the first CMIP exercises, a cold model bias has been identified in this region, however, its attribution is not obvious and may be different from one model to another. Our study focuses on a multi-model comparison of the CMIP6 simulations used to investigate the climate variability in this area to answer the next questions: (1) are the biases in HMA reduced in the new generation of climate models? (2) Do the model biases impact the simulated climate trends? (3) What are the links between the model biases in temperature, precipitation, and snow cover extent? (4) Which climate trajectories can be projected in this area until 2100? An analysis of 27 models over 1979-2014 still show a cold bias in near-surface air temperature over the HMA and TP reaching an annual value of -2.0 °C (± 3.2 °C), associated with an over-extended relative snow cover extent of 53 % (± 62 %), and a relative excess of precipitation of 139 % (± 38 %), knowing that the precipitation biases are uncertain because of the undercatch of solid precipitation in observations. Model biases and trends do not show any clear links, suggesting that biased models should not be excluded in trend and projections analysis, although non-linear effects related to lagged snow cover feedbacks could be expected. On average over 2081-2100 with respect to 1995-2014, for the scenarios SSP126, SSP245, SSP370, and SSP585, the 9 available models shows respectively an increase in annual temperature of 1.9 °C (± 0.5 °C), 3.4 °C (± 0.7 °C), 5.2 °C (± 1.2 °C), and 6.6 °C (± 1.5 °C); a relative decrease in the snow cover extent of 10 % (± 4.1 %), 19 % (± 5 %), 29 % (± 8 %), and 35 % (± 9 %); and an increase in total precipitation of 9 % (± 5 %), 13 % (± 7 %), 19 % (± 11 %), and 27 % (± 13 %). Further analyses will be considered to investigate potential links between the biases at the surface and those at higher tropospheric levels as well as with the topography. The models based on high resolution do not perform better than the coarse-gridded ones, suggesting that the race to high resolution should be considered as a second priority after the developments of more realistic physical parameterizations.</p>

Sample pre-treatment techniques for use with ICP-MS hyphenated techniques for elemental speciation in biological samples

2017 ◽  
Vol 32 (1) ◽  
pp. 58-77 ◽  
Author(s):  
Han Wang ◽  
Xiaolan Liu ◽  
Kai Nan ◽  
Beibei Chen ◽  
Man He ◽  
...  
Keyword(s):  
Biological Samples ◽  
State Of The Art ◽  
Sample Pretreatment ◽  
The State ◽  
Elemental Speciation ◽  
Hyphenated Techniques ◽  
Treatment Techniques ◽  
Icp Ms ◽  
Pre Treatment

This review will focus specifically on the state of the art of novel sample pretreatment methods which have been combined with ICP-MS based hyphenated techniques for elemental speciation in biological samples.

Impacts of N, N'-diphenyl-1, 4-phenylenediamine (DPPD) Antioxidant Additive in Jatropha Biodiesel Blends to Reduce NOx Emission of a Multi Cylinder Vehicle Type Diesel Engine

2013 ◽  
Vol 774-776 ◽  
pp. 784-790
Author(s):  
S.M. Palash ◽  
M.A. Kalam ◽  
H.H. Masjuki ◽  
B.M. Masum
Keyword(s):  
Diesel Engine ◽  
Engine Performance ◽  
Exhaust Emission ◽  
Antioxidant Additive ◽  
Biodiesel Blends ◽  
Market Expansion ◽  
Treatment Techniques ◽  
Pre Treatment ◽  
Biodiesel Fuels ◽  
Full Throttle

To meet stringent exhaust emission norms worldwide, various exhaust pre-treatment and post-treatment techniques have been employed in modern engines. Using antioxidant additives in biodiesel fuels is a promising and effective NOx reduction technology. Non-edible jatropha oil based methyl ester was produced and blended with conventional diesel. Five fuel samples (Diesel, JB5, JB5DPPD0.15%, JB15 and JB15DPPD0.15%) were tested for their use as substitute fuel for a radiator-cooled four cylinder diesel engine. Experiment results show that DPPD antioxidant additive could be reduced NOx emission significantly with slight penalty on engine performance as well as CO and HC emission. However, when compared to diesel combustion the emissions of HC and CO were found nearly same or below. By addition of 0.15% (m) DPPD additive in JB5 and JB15 reduction of NOx emission were 12.68% and 13.36 % compared to biodiesel blends without additive at full throttle position. As conclusion, JB5 and JB15 with addition of 0.15% (m) can be used in four cylinder diesel engine to reduce NOx and consequently overcome the barrier to market expansion of biodiesel fuels.

Delineating active faults across the Narmada-Son Lineament (NSL), India using the technique of Fracture Induced Electromagnetic Radiation (FEMR)

2021 ◽  
Author(s):  
Shreeja Das ◽  
Jyotirmoy Mallik
Keyword(s):  
Electromagnetic Radiation ◽  
Process Zone ◽  
Active Faults ◽  
Central India ◽  
Earthquake Forecasting ◽  
Tectonic Activity ◽  
Eurasian Plate ◽  
Near Surface ◽  
Crustal Stresses ◽  
Tectonically Active

<p>The Fracture Induced Electromagnetic Radiation (FEMR) technique has gradually progressed in the past decade as a useful geophysical tool to determine the direction and magnitude of recent crustal stresses, visualize the modification and realignment of stresses inside tunnels thus proving to be an important precursor for geohazards, earthquake forecasting, as well as delineate landslide-prone slip planes in unstable regions. Its working principle is based on the generation of geogenic electromagnetic radiation emanating from the brittle rock bodies that are fractured being subjected to an incremental increase of the differential stress in the near-surface of the Earth’s crust. The “Process zone” at the fractured crack tip contains numerous microcracks which subsequently creates dipoles due to the polarization of charges on such microcrack tips which rapidly oscillates emitting FEMR waves of frequencies between KHz to MHz range. The coalescence of the microcracks eventually leads to a macro failure dampening the amplitude of the FEMR pulses. The attenuation of FEMR pulses is comparatively lesser than seismic waves making it a more efficient precursor to potential tectonic activities indicating an upcoming earthquake a few hours/days before the actual event. In the current study, we have attempted to exploit this technique to identify the locations of the potential active faults across the tectonically active Narmada-Son Lineament (NSL), Central India. Although the first tectonic stage involved rifting and formation of the NSL during the Precambrian time, the rifting continued at least till the time of Gondwana deposition. Later, tectonic inversion took place as a result of the collision between the Indian and the Eurasian plate resulting in reverse reactivation of the faults. Episodic reverse movement along NSL caused recurrent earthquakes and linear disposition of the sediments that were deposited at the foothills of the Satpura Horst. Although the origin of East-West trending NSL dates back to the Precambrian time, it is very much tectonically active as manifested by recent earthquakes. The study has been conducted by taking linear FEMR readings across 3 traverses along the NSL which on analysis provides an idea about the potential active faults, their locations, and frequency of occurrence. The accumulation of strain in the brittle rocks that can eventually lead to a macro failure is demarcated as an anomalous increase in the amplitude of the FEMR pulses indicative of an upcoming tectonic episode in the region. To further corroborate the analysis, we have attempted to determine the neo-tectonic activity in the region by calculating the morphometric parameters across the Khandwa-Itarsi-Jabalpur region, Central India. Finally, we attempt to comment on the tectonic evolution of Central India in the recent past. We also encourage researchers to adapt the novel technique of FEMR which is swift, affordable, and feasible compared to conventional techniques deployed to survey the active tectonics of a region.</p>

Evaluation of pre-treatment techniques for shale gas produced water to facilitate subsequent treatment stages

2019 ◽  
Vol 7 (1) ◽  
pp. 102878 ◽  
Author(s):  
Meicheng Wang ◽  
Min Wang ◽  
Dong Chen ◽  
Qi Gong ◽  
Sicong Yao ◽  
...  
Keyword(s):  
Shale Gas ◽  
Produced Water ◽  
Subsequent Treatment ◽  
Treatment Techniques ◽  
Pre Treatment

scholarly journals AMS-14C Chronology of a Lacustrine Sequence from Lake Langano (Main Ethiopian Rift): Correction and Validation Steps in Relation with Volcanism, Lake Water and Carbon Balances

Radiocarbon ◽  
2002 ◽  
Vol 44 (1) ◽  
pp. 75-92 ◽  
Author(s):  
Elisabeth Gibert ◽  
Yves Travi ◽  
Marc Massault ◽  
Jean-Jacques Tiercelin ◽  
Tesfaye Chernet
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Regional Scale ◽  
Ethiopian Rift ◽  
Lake Basin ◽  
Main Ethiopian Rift ◽  
Tectonically Active ◽  
Half Graben ◽  
Rift Lake ◽  
The 1960S ◽  
Radiocarbon Chronology

Located in the Ziway-Shala Basin of the Main Ethiopian Rift, Lake Langano is part of an asymmetric half-graben, defined by a series of north-northeast-trending faults in the tectonically active zone of the rift. A 15-m deep succession of organic homogeneous muds, silts, bioclastic sands, and pyroclastic layers was cored in 1994. The definition of a certified radiocarbon chronology on these deposits required the indispensable establishment of modern hydrological and geochemical balances. The isotopic contents of the total dissolved inorganic carbon (TDIC) of surface water clearly show the influence of a deep CO2 rising along the main fault crossing the lake basin. The 5.8 pMC disequilibrium existing in 1994 with the atmosphere likely produces the aging of authigenic materials developing at the lake surface. However, with a mean residence time of ~15 years, this apparent 14C aging of Lake Langano water still integrates the 14C produced by the nuclear tests in the 1960s. Reconstructing the natural 14C activity of the lake TDIC allows for the quantification of the deep CO2 influence, and for the correction of AMS-14C datings performed along the core. The correction of the AMS-14C chronology defined on Lake Langano allows for a better understanding of paleohydrological changes at a regional scale for at least the last 12,700 cal BP.

scholarly journals An integrated approach to investigate climate-driven rockfall occurrence in high alpine slopes: the Bessanese glacial basin, Western Italian Alps

2020 ◽  
Vol 17 (11) ◽  
pp. 2591-2610
Author(s):  
Cristina Viani ◽  
Marta Chiarle ◽  
Roberta Paranunzio ◽  
Andrea Merlone ◽  
Chiara Musacchio ◽  
...  
Keyword(s):  
Climate Change ◽  
Active Layer ◽  
Integrated Approach ◽  
Slope Instability ◽  
High Mountain ◽  
Positive Temperature ◽  
Rock Slopes ◽  
Italian Alps ◽  
Near Surface ◽  
Basin Scale

Abstract Rockfalls are one of the most common instability processes in high mountains. They represent a relevant issue, both for the risks they represent for (infra) structures and frequentation, and for their potential role as terrestrial indicators of climate change. This study aims to contribute to the growing topic of the relationship between climate change and slope instability at the basin scale. The selected study area is the Bessanese glacial basin (Western Italian Alps) which, since 2016, has been specifically equipped, monitored and investigated for this purpose. In order to provide a broader context for the interpretation of the recent rockfall events and associated climate conditions, a cross-temporal and integrated approach has been adopted. For this purpose, geomorphological investigations (last 100 years), local climate (last 30 years) and near-surface rock/air temperatures analyses, have been carried out. First research outcomes show that rockfalls occurred in two different geomorphological positions: on rock slopes in permafrost condition, facing from NW to NE and/or along the glacier margins, on rock slopes uncovered by the ice in the last decades. Seasonal thaw of the active layer and/or glacier debutressing can be deemed responsible for slope failure preparation. With regard to timing, almost all dated rock falls occurred in summer. For the July events, initiation may have been caused by a combination of rapid snow melt and enhanced seasonal thaw of the active layer due to anomalous high temperatures, and rainfall. August events are, instead, associated with a significant positive temperature anomaly on the quarterly scale, and they can be ascribed to the rapid and/or in depth thaw of the permafrost active layer. According to our findings, we can expect that in the Bessanese glacierized basin, as in similar high mountain areas, climate change will cause an increase of slope instability in the future. To fasten knowledge deepening, we highlight the need for a growth of a network of high elevation experimental sites at the basin scale, and the definition of shared methodological and measurement standards, that would allow a more rapid and effective comparison of data.

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