scholarly journals Paleoenvironmental Interpretation of Last Millennium Sediments in the Marriaga Swamp, Atrato Delta, Colombia

2021 ◽  
Vol 31 (1) ◽  
pp. 9-24
Author(s):  
Liliana Betancurth Montes ◽  
Julio Eduardo Cañón Barriga
Keyword(s):  
Heavy Metal ◽  
Organic Carbon Content ◽  
Last Millennium ◽  
Paleoenvironmental Reconstruction ◽  
Biological Productivity ◽  
Dry Period ◽  
Statistical Correlations ◽  
Paleoenvironmental Interpretation ◽  
Geochemical Analyses ◽  
Flooding Events

This paper presents the first paleoenvironmental reconstruction of the last 1,130 a of the Marriaga Swamp in the Atrato River delta in northwestern Colombia. The geochemical analyses of a 220 cm sediment core retrieved from the swamp reveal interesting climatic episodes and sedimentary changes in the last millennium. We split the core into three segments, according to sediment features, organic carbon content (OC), and geological ages. Records show different alternations of humid and dry periods, biological productivity, carbonate precipitation, weathering grade, and high heavy metal concentrations. The segments also concur with the geochemical differences determined by (Zr+Rb)/Sr, Ca/Ti Mn/Fe, OC/Ti, Mg/Ca Ba/Al, Sr/Al, and Ca/Al ratios. The older sequence (between 1,130 ± 90 a and 870 ± 70 a) shows a dry period with intermittent flooding events and high OC production in subareal conditions, followed by a more humid environment between 870 ± 70 a and 530 ± 40 a, with depletion of trace element ratios and OC. The more recent period (530 ± 40 a to present) evinces an environment dominated by the fluvial regime, based on a lower Ca/Al ratio and a rise of OC. The statistical correlations display three main clusters that distinguish among organic-biological productivity, bedrock source components, and heavy metal inputs.

Holocene glacier history of northeastern Cordillera Darwin, southernmost South America (55°S)

2021 ◽  
pp. 1-16
Author(s):  
Scott A. Reynhout ◽  
Michael R. Kaplan ◽  
Esteban A. Sagredo ◽  
Juan Carlos Aravena ◽  
Rodrigo L. Soteres ◽  
...  
Keyword(s):  
South America ◽  
Last Millennium ◽  
Glacial History ◽  
Dry Period ◽  
The North ◽  
Southward Shift ◽  
History Of ◽  
Glacial Expansion ◽  
The Antarctic ◽  
Glacial Advance

Abstract In the Cordillera Darwin, southernmost South America, we used 10Be and 14C dating, dendrochronology, and historical observations to reconstruct the glacial history of the Dalla Vedova valley from deglacial time to the present. After deglacial recession into northeastern Darwin and Dalla Vedova, by ~16 ka, evidence indicates a glacial advance at ~13 ka coeval with the Antarctic Cold Reversal. The next robustly dated glacial expansion occurred at 870 ± 60 calendar yr ago (approximately AD 1150), followed by less-extensive dendrochronologically constrained advances from shortly before AD 1836 to the mid-twentieth century. Our record is consistent with most studies within the Cordillera Darwin that show that the Holocene glacial maximum occurred during the last millennium. This pattern contrasts with the extensive early- and mid-Holocene glacier expansions farther north in Patagonia; furthermore, an advance at 870 ± 60 yr ago may suggest out-of-phase glacial advances occurred within the Cordillera Darwin relative to Patagonia. We speculate that a southward shift of westerlies and associated climate regimes toward the southernmost tip of the continent, about 900–800 yr ago, provides a mechanism by which some glaciers advanced in the Cordillera Darwin during what is generally considered a warm and dry period to the north in Patagonia.

scholarly journals Spatial Connections between Microplastics and Heavy Metal Pollution within Floodplain Soils

2022 ◽  
Vol 12 (2) ◽  
pp. 595
Author(s):  
Collin J. Weber ◽  
Jens Hahn ◽  
Christian Opp
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Wide Distribution ◽  
Soil Material ◽  
Statistical Correlations ◽  
Floodplain Soils ◽  
Icp Ms ◽  
Metal Contents ◽  
Sediment Layers ◽  
Deposition Conditions

Soils contain an increasing number of different pollutants, which are often released into the environment by human activity. Among the “new” potential pollutants are plastics and microplastics. “Recognized” pollutants such as heavy metals, of geogenic and anthropogenic origin, now meet purely anthropogenic contaminants such as plastic particles. Those can meet especially in floodplain landscapes and floodplain soils, because of their function as a temporary sink for sediments, nutrients, and pollutants. Based on a geospatial sampling approach, we analyzed the soil properties and heavy metal contents (ICP-MS) in soil material and macroplastic particles, and calculated total plastic concentrations (Ptot) from preliminary studies. Those data were used to investigate spatial connections between both groups of pollutants. Our results from the example of the Lahn river catchment show a low-to-moderate contamination of the floodplain soils with heavy metals and a wide distribution of plastic contents up to a depth of two meters. Furthermore, we were able to document heavy metal contents in macroplastic particles. Spatial and statistical correlations between both pollutants were found. Those correlations are mainly expressed by a comparable variability in concentrations across the catchment and in a common accumulation in topsoil and upper soil or sediment layers (0–50 cm). The results indicate comparable deposition conditions of both pollutants in the floodplain system.

scholarly journals Study on the Mechanism of Organic Matter Enrichment in Early Cambrian Marine Shales in the Lower Yangtze Area, South China: An Example Using Well JXY1

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Sihong Cheng ◽  
Bin Li ◽  
Kun Zhang ◽  
Weiwei Liu ◽  
Jun Peng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Oxygen Isotope ◽  
Water Body ◽  
Organic Carbon Content ◽  
Hydrocarbon Generation ◽  
Early Cambrian ◽  
Biological Productivity ◽  
Carbon And Oxygen Isotope ◽  
Lower Yangtze ◽  
Hydrothermal Activities

The abundance of organic matter in shales, which has a direct effect on the hydrocarbon generation potential of shales, is an important organic geochemical parameter for evaluating shale gas reservoirs. The total organic carbon content (TOC content) in shale is controlled by the abundance of original sedimentary organic matter. Therefore, it is very important to study the mechanism of organic matter enrichment in shale. In this paper, the Lower Cambrian marine shales from the Lower Yangtze region are selected as the research subject, most of which originate from a typical area well called Well JXY1. The degree of pyritization (DOP) is used to characterize the redox environment of the water body, while the P/Al ratio is used to analyze the biological productivity of paleoseawater. The paleosalinity of seawater is calculated via carbon and oxygen isotope analysis. In addition, the early Cambrian hydrothermal activities were studied by using core description; Si, Al, Fe, and Mn elemental analysis; and oxygen isotope calculations. The results show that during the early Cambrian Wangyinpu sedimentary period, the seawater was an anaerobic water body with H2S, and the oxygen concentration was approximately 0 mL/L. In the middle stages of the Wangyinpu sedimentary period, the water body had the strongest reducibility and the highest biological productivity. Moreover, the paleoocean in this period between the Yangtze plate and the Cathaysian plate was greatly affected by hydrothermal activities, with temperatures ranging from 90°C to 120°C. Active hydrothermal activities promoted high biological productivity and an anaerobic environment, both of which were conducive to the preservation and enrichment of organic matter, resulting in extremely high TOC content in the Wangyinpu shales (from 6.5% to approximately 16%).

scholarly journals Impact of Brick Kilns’ Emission on Soil Quality of Agriculture Fields in the Vicinity of Selected Bhaktapur Area of Nepal

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Gunjan Bisht ◽  
Sanjila Neupane
Keyword(s):  
Heavy Metal ◽  
Soil Quality ◽  
Heavy Metal Contamination ◽  
Nutrient Content ◽  
Physical Parameters ◽  
Organic Carbon Content ◽  
Brick Kiln ◽  
Entire Study ◽  
Brick Kilns

The study was conducted to evaluate soil quality and impact of brick kiln on different physicochemical parameters of soils of agricultural field, located in the vicinity of Bhaktapur, Nepal. The study was carried out by determining the physicochemical characteristics of soil, soil fertility, and heavy metal contamination of soil. During the entire study period, water absorptivity of soil ranged from 2.4 to 3.3 mg/L, pH varies from 5.885 to 7.64, and organic carbon content and organic matter varied from 0.277 to 0.93%, from 0.477% to 1.603%, respectively. Nutrient content, that is, sulfate and nitrate concentration, in the soil ranged from 0.829 to 3.764 mol/L and from 0.984 to 29.99 mol/L, respectively. The findings revealed that concentrations of heavy metals (chromium and lead) were within permissible limit, although the levels were higher in soil at 50 m and decrease farther from brick kiln. However, the physical parameters and nutrient content were deficient in soil at 50 m while increasing gradually at distances of 100 m and 150 m. The variation of result obtained for physical parameters supports the fact that quality of soil in terms of heavy metal content and nutrient content was directly proportional to the distance from the kiln; that is, the quality of soil increased with increasing distance.

scholarly journals Geoarchaeological and paleoenvironmental reconstruction of the Late Quaternary climate- environmental-human nexus in the Kurdistan region of Iraq

2020 ◽  
Author(s):  
Luca Forti ◽  
Eleonora Regattieri ◽  
Anna Maria Mercuri ◽  
Ilaria Mazzini ◽  
Andrea Pezzotta ◽  
...  
Keyword(s):  
Land Use ◽  
Late Quaternary ◽  
Climatic Variability ◽  
Archaeological Sites ◽  
Paleoenvironmental Reconstruction ◽  
Human Land Use ◽  
Quaternary Climate ◽  
Geochemical Analyses ◽  
Sandy Sediments ◽  
Origin Of Agriculture

<p>During the late Quaternary, Iraqi Kurdistan was the scenario of several fundamental human-related<br>events including the dispersion of Homo in Asia and Europe, the origin of agriculture, the beginning<br>of urbanization, and the formation of the first state entities. We present the initial results of a<br>geoarchaeological investigation in this area, which aims to reconstruct a detailed framework of the<br>relationship between climatic changes, landscape responses, human adaptation, and settlement<br>distribution during the Late Quaternary. Paleoenvironmental and paleoclimatic data were collected<br>from two key areas: the territory of the Navkur and Faideh plains, in northern Kurdistan, and a portion<br>of the Erbil plain, in southern Kurdistan. In the two regions, the Land of Niniveh and MAIPE<br>archaeological missions are operating. Remote sensing, GIS analyses, and geomorphological survey<br>are the tools used for the geomorphological reconstruction of ancient hydrology (fluvial pattern) and<br>the evolution of distinct landforms. Geochemical and geochronological analyses on speleothems from<br>the Zagros piedmont caves of same region provide information on Holocene climatic variability in<br>the area. Whereas environmental settings and human land use are investigated on the basis of<br>sedimentological, palynological, micropaleontological, and geochemical analyses of a fluvio-<br>lacustrine sequences preliminary dated between 40 and 9 ka BP. The lacustrine sequence is composed<br>by clayey and silt-sandy sediments alternating calcareous and organic matter-rich layers.<br>Environmental and geomorphological data have been compared with archaeological information<br>(mostly the chronological distribution of the archaeological sites) to interpret exploitation of natural<br>resources, the settlement dynamics and shift in land use. </p>

scholarly journals Paleoenvironmental reconstruction of the Pleistocene site of Oued Sarrat (Northwestern Tunisia) using mineralogical and geochemical data

2018 ◽  
Vol 27 (2) ◽  
pp. 316-322
Author(s):  
Narjess Karoui-Yaakoub ◽  
Moncef Said Mtimet ◽  
Semeh Bejaoui ◽  
Bienvenido Martínez-Navarro
Keyword(s):  
High Energy ◽  
Geochemical Data ◽  
Paleoenvironmental Reconstruction ◽  
Total Contribution ◽  
Chemical Test ◽  
Calcium Carbonates ◽  
Mineralogical Study ◽  
Marine Influence ◽  
Middle And Late Pleistocene ◽  
Geochemical Analyses

The mineralogical and geochemical analyses of Pleistocene sediments and mollusks shells (gastropods and bivalves) from the archaeopaleontological site of Oued Sarrat (Tejerouine, NW Tunisia) permitted us to determine the paleoenvironmental conditions and to reconstruct the local depositional environment during the Middle and Late Pleistocene. The mineralogical cortege of the sediments, for all the analyzed samples, records the characteristics of a mixture ofsilica and calcite dominance with a small fraction of gypsum and aragonite. The mineralogical analyses of all mollusk species reflect a cortege dominated by aragonite, associated with low amounts of calcite, silica, hematite and goethite. We consider that the domin- ance of aragonite indicates that the tests have not yet or little undergone mineralogical transformations linked to the phenomena of fossilization, as evidenced by the absence or low calcite content. On the other hand, the low percentages of silica, goethite and hematite are probably related to the existence of impurities and sediments trapped in lodges, or  adhered to the shell surface. The mineralogical data confirm a composition dominated by calcium carbonates, expressed by high contents of CaO and CO2, reflecting a chemical test of organisms’ development in continental environment.This kind of environment is characterized by the absence of MgO, which is usually present in the organisms’ tests developed in marine environment. However, the contents of SiO2, Fe2O3, Al2O3 are related, as it was reported during the mineralogical study, to the lithological impurities trapped mainly in the lodges of helicides. Mineralogical and geochemical data tracing, carried out on sediments and tests, converge to deduce the establishment of paleoenvironment attributable to fluvial deposition of sufficiently high energy where the ultrafine fractions of clay minerals are remarkably lacking. The absence of indicators of marine chemistry such as magnesium in sediments and in the tests of organisms confirms almost total contribution of the continental meteoric water without marine influence. Such environment, however, is affected by intermittent episodes of aridity as attested by the presence of evaporate minerals such as gypsumand aragonite.

scholarly journals Depositional conditions and petroleum potential of the Middle Triassic Passhatten Member (Bravaisberget Formation), Spitsbergen

2014 ◽  
Vol 35 (1) ◽  
pp. 41-71
Author(s):  
Przemysław Karcz
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Middle Triassic ◽  
Oxygen Deficiency ◽  
Intermediate Stage ◽  
Black Shales ◽  
Water Dynamics ◽  
Maximum Temperature ◽  
Organic Carbon Content ◽  
Biological Productivity

Abstract The Passhatten Member (Anisian-Ladinian) is the most westward exposure of the Middle Triassic sedimentary sequence of Spitsbergen. The member has an average organic carbon of 2.21 wt %. The sediments were deposited in a shallow shelf environment under conditions of high biological productivity stimulated by a well−developed upwelling system and an enhanced nutrient supply from land areas. The high biological productivity caused a high supply of organic particles to the shelf bottom. Decomposition of organic matter initiated oxygen deficiency in the bottom waters; however, bottom water dynamics on the shallow shelf temporarily replenished the oxygen. Consequently, the Passhatten Mb section is bioturbated, even in thick black shale horizons and consists of alternately spaced lithological layers with variable organic carbon content. The organic matter is dominated by type II kerogen with a mixture of strongly altered marine and/or land derived organic matter. Calculated initial hydrogen index values suggest oil−prone organic matter similar to kerogen I and II types. The organic matter is in the upper intermediate stage of thermo−cata− lytic alteration, close to the cata- and metagenetic boundary. Maturity indicators including Rock−Eval, Maximum Temperature, Organic Matter Transformation Ratio, Residual Car− bon content, as well as the volume of methane generated suggest mature to overmature organic matter. Methane potential retained in the black shales sequence is significant. Unexpelled gas is estimated at 395 mcf/ac−ft for the examined section.

scholarly journals Application Research of Biochar for the Remediation of Soil Heavy Metals Contamination: A Review

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3167
Author(s):  
Sheng Cheng ◽  
Tao Chen ◽  
Wenbin Xu ◽  
Jian Huang ◽  
Shaojun Jiang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Organic Carbon ◽  
Ph Value ◽  
Performance Characteristics ◽  
Future Research ◽  
Organic Carbon Content ◽  
Agricultural Crop ◽  
Thermochemical Transformation ◽  
And Performance

Soil contamination by heavy metals threatens the quality of agricultural products and human health, so it is necessary to choose certain economic and effective remediation techniques to control the continuous deterioration of land quality. This paper is intended to present an overview on the application of biochar as an addition to the remediation of heavy-metal-contaminated soil, in terms of its preparation technologies and performance characteristics, remediation mechanisms and effects, and impacts on heavy metal bioavailability. Biochar is a carbon-neutral or carbon-negative product produced by the thermochemical transformation of plant- and animal-based biomass. Biochar shows numerous advantages in increasing soil pH value and organic carbon content, improving soil water-holding capacity, reducing the available fraction of heavy metals, increasing agricultural crop yield and inhibiting the uptake and accumulation of heavy metals. Different conditions, such as biomass type, pyrolysis temperature, heating rate and residence time are the pivotal factors governing the performance characteristics of biochar. Affected by the pH value and dissolved organic carbon and ash content of biochar, the interaction mechanisms between biochar and heavy metals mainly includes complexation, reduction, cation exchange, electrostatic attraction and precipitation. Finally, the potential risks of in-situ remediation strategy of biochar are expounded upon, which provides the directions for future research to ensure the safe production and sustainable utilization of biochar.

scholarly journals Organic matter heterogeneity and shale oil significance in Triassic Zhangjiatan shale, Ordos Basin, China

2021 ◽  
pp. 014459872110393
Author(s):  
Xiaoyan Li ◽  
Jincai Tuo ◽  
Chenjun Wu ◽  
Honggang Xin ◽  
Mingfeng Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Vertical Profile ◽  
Sedimentary Environment ◽  
Ordos Basin ◽  
Immature Stage ◽  
Source Rocks ◽  
Organic Carbon Content ◽  
Shale Oil ◽  
Oil Resources ◽  
Geochemical Analyses

Organic matter heterogeneity exerts an important impact on the generation, evaluation, and exploitation of shale oil resources. In the past, only a limited number of analytical samples that represented the contribution or influence of high or low organic matter abundance intervals were used to represent an entire set of thick source rocks, and based on this limitation, occasionally researchers have reached incorrect conclusions. Here, the heterogeneity of organic matter and its significance to shale oil in the Triassic Zhangjiatan shale of the Ordos Basin were discussed based on sedimentary and geochemical analyses. Our results indicate that (1) the Chang 73 shale within the study area is characterized by high abundance, good quality, strong heterogeneity, and segmented enrichment in the vertical profile. The primary organic matter type was type II1, and this was followed by types I, II2, and III that exhibited three changing trends in the vertical profile. Organic matter maturity is primarily at the immature stage. (2) Additionally, we observed that the organic matter heterogeneity of Chang 73 shale was related to changes in lithology, sedimentary environment, paleoproductivity, terrigenous influence, and event action (such as volcanism and hydrothermal processes). The abundance of organic matter is the result of the coupling control of these processes. In the process of organic matter deposition, if volcano or hydrothermal activities occurred, the organic matter was abnormally enriched, and the total organic carbon content exceeded 20% and could even be as high as 40%. (3) Finally, we observed at least nine enrichment layers that were controlled by the coupling of different geological factors, and there were four potential target resource layers corresponding to the hydrothermal sedimentary area.

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