scholarly journals Thenardite after mirabilite deposits as a cool climate indicator in the geological record: lower Miocene of Central Spain

2014 ◽  
Vol 10 (4) ◽  
pp. 3223-3253
Author(s):  
M. J. Herrero ◽  
J. I. Escavy ◽  
B. C. Schreiber
Keyword(s):  
Sedimentary Environment ◽  
Lower Miocene ◽  
Sedimentary Environments ◽  
Diagenetic Alteration ◽  
Time Period ◽  
Industrial Mineral ◽  
Climate Indicator ◽  
Mammal Assemblages ◽  
Cool Climate

Abstract. Evaporites are commonly used as indicators of different paleoclimates and sedimentary environments, as well as being geological resources of great economic interest. Ordinarily the presence of evaporites is related to warm and arid environmental conditions, but there are evaporitic minerals, like mirabilite, that form by cooling and a concentration mechanism based on cooling and/or freezing. The diagenetic transformation of mirabilite into thenardite in the upper part of the lower Miocene unit of the Tajo basin (Spain) resulted in the largest reserves of this important industrial mineral in Europe. This unit was formed in a time period (~ 18.4 Ma) that, in other basins of the Iberian Peninsula, is characterized by the existence of particular mammal assemblages appropriate to a relatively cool and arid climate. Determining the origin of the thenardite deposits as related to the diagenetic alteration of a pre-existing mirabilite permits the establishment and characterization of the sedimentary environment where it was formed and also suggests use as a possible analogue with comparable deposits from extreme conditions such as Antarctica or Mars.

scholarly journals Thenardite after mirabilite deposits as a cool climate indicator in the geological record: lower Miocene of central Spain

2015 ◽  
Vol 11 (1) ◽  
pp. 1-13 ◽  
Author(s):  
M. J. Herrero ◽  
J. I. Escavy ◽  
B. C. Schreiber
Keyword(s):  
Sedimentary Environment ◽  
Lower Miocene ◽  
Sedimentary Environments ◽  
Diagenetic Alteration ◽  
Time Period ◽  
Industrial Mineral ◽  
Salt Deposits ◽  
Climate Indicator ◽  
Mammal Assemblages

Abstract. Salt deposits are commonly used as indicators of different paleoclimates and sedimentary environments, as well as being geological resources of great economic interest. Ordinarily, the presence of salt deposits is related to warm and arid environmental conditions, but there are salts, like mirabilite, that form by cooling and a concentration mechanism based on cooling and/or freezing. The diagenetic transformation of mirabilite into thenardite in the upper part of the lower Miocene unit of the Tajo basin (Spain) resulted in the largest reserves of this important industrial mineral in Europe. This unit was formed in a time period (~18.4 Ma) that, in other basins of the Iberian Peninsula, is characterized by the existence of particular mammal assemblages appropriate to a relatively cool and arid climate. Determining the origin of the thenardite deposits as related to the diagenetic alteration of a pre-existing mirabilite permits the establishment and characterization of the sedimentary environment where it was formed and also suggests use as a possible analog with comparable deposits from extreme conditions such as Antarctica or Mars.

Postglacial Diatom Stratigraphy in Relation to the Recession of Glacial Lake Agassiz

1975 ◽  
Vol 5 (4) ◽  
pp. 529-540 ◽  
Author(s):  
J.C. Ritchie ◽  
L.K. Koivo
Keyword(s):  
Sandy Beach ◽  
Sedimentary Environment ◽  
Glacial Lake ◽  
Lake Agassiz ◽  
Organic Detritus ◽  
Sedimentary Environments ◽  
Grand Rapids ◽  
Glacial Lake Agassiz ◽  
Diatom Stratigraphy ◽  
Beach Sands

The sediment and diatom stratigraphy of a small pond on The Pas moraine, near Grand Rapids, Manitoba, reveals a change in sedimentary environment related directly to the last stages of Glacial Lake Agassiz. Beach sands were replaced by clay 7300 14C y. a., then by organic silt and, at 4000 14C y. a. by coarse organic detritus; the corresponding diatom assemblages were (I) a predominantly planktonic spectrum in beach sands, (II) a rich assemblage of nonplanktonic forms, and (III) a distinctly nonplanktonic acidophilous spectrum. These results confirm Elson's (1967) reconstruction of the extent and chronology of the final (Pipun) stage of Glacial Lake Agassiz. The sedimentary environments change from a sandy beach of a large lake at 7300 BP to a small, shallow eutrophic pond with clay and silt deposition from 7000 to 4000 BP. From 4000 BP to the present, organic detritus was deposited in a shallow pond that tended toward dystrophy.

scholarly journals The hydrological response of baseflow in fractured mountain areas

2009 ◽  
Vol 6 (2) ◽  
pp. 3359-3384 ◽  
Author(s):  
A. Millares ◽  
M. J. Polo ◽  
M. A. Losada
Keyword(s):  
Hydrological Model ◽  
Water System ◽  
Essential Element ◽  
Mediterranean Area ◽  
Mountainous Areas ◽  
Mountain Areas ◽  
Linear Behavior ◽  
Time Period ◽  
Recession Curves

Abstract. The study of baseflow in mountainous areas of basin headwaters, where the characteristics of the often fractured materials are very different to the standard issues concerning porous material applied in conventional hydrogeology, is an essential element in the characterization and quantification of water system resources. Their analysis through recession fragments provides information on the type of response of the sub-surface and subterranean systems and on the average relation between the storage and discharge of aquifers, starting from the joining of these fragments into a single curve, the Master Recession Curve (MRC). This paper presents the generation of the downward MRC over fragments selected after a preliminary analysis of the recession curves, using a hydrological model as the methodology for the identification and the characterization of quick sub-surface flows flowing through fractured materials. The hydrological calculation has identified recession fragments through surface runoff or snowmelt and those periods of intense evapotranspiration. The proposed methodology has been applied to three sub-basins belonging to a high altitude mountain basin in the Mediterranean area, with snow present every year, and their results were compared with those for the upward concatenation of the recession fragments. The results show the existence of two different responses, one quick (at the sub-surface, through the fractured material) and the other slow, with linear behavior which takes place in periods of 10 and 17 days, respectively and which is linked to the dimensions of the sub-basin. In addition, recesses belonging to the dry season have been selected in order to compare and validate the results corresponding to the study of recession fragments. The comparison, using these two methodologies, which differ in the time period selected, has allowed us to validate the results obtained for the slow flow.

scholarly journals Geochemical Features of Redox-Sensitive Trace Metals in Sediments under Oxygen-Depleted Marine Environments

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1021
Author(s):  
Moei Yano ◽  
Kazutaka Yasukawa ◽  
Kentaro Nakamura ◽  
Minoru Ikehara ◽  
Yasuhiro Kato
Keyword(s):  
Sedimentary Environment ◽  
Organic Matter Content ◽  
Oxygen Depletion ◽  
Major And Trace Elements ◽  
Matter Content ◽  
Open Ocean ◽  
Chemical Compositions ◽  
Marine Environments ◽  
High Productivity ◽  
Sedimentary Environments

Organic- and sulfide-rich sediments have formed in oxygen-depleted environments throughout Earth’s history. The fact that they are generally enriched in redox-sensitive elements reflects the sedimentary environment at the time of deposition. Although the modern ocean is well oxidized, oxygen depletion occurs in certain areas such as restricted basins and high-productivity zones. We measured bulk chemical compositions (major and trace elements, total organic carbon, and total sulfur) of organic- and sulfide-rich sediments collected from eight areas having oxygen-depleted water to discuss relationships between geochemical features and sedimentary environments. Major elemental compositions generally show mixtures of terrigenous detritus and biogenic carbonate. Some redox-sensitive elements might be controlled by organic matter content, whereas others could be contained in sulfide minerals in sediments. In particular, Mo and U show a characteristic trend; areas with higher Mo and U—at least partially owing to a depositional process called the “particulate shuttle”—generally correspond to regions influenced by the open ocean. In contrast, areas with lower Mo and U are more restricted marine environments. This suggests that the degree of Mo and U enrichment reflects the geography in terms of proximity to the open ocean, or the degree of the supply of these elements from the open ocean.

Sedimentary environment prediction of grain-size data based on machine learning approach

2020 ◽  
Vol 8 (3) ◽  
pp. SL71-SL78
Author(s):  
Qiao Su ◽  
Yanhui Zhu ◽  
Fang Hu ◽  
Xingyong Xu
Keyword(s):  
Machine Learning ◽  
Grain Size ◽  
Prediction Model ◽  
Sedimentary Environment ◽  
Machine Learning Algorithms ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Data Set ◽  
Sedimentary Environments ◽  
Size Data

Grain size is one of the most important records for sedimentary environment, and researchers have made remarkable progress in the interpretation of sedimentary environments by grain size analysis in the past few decades. However, these advances often depend on the personal experience of the scholars and combination with other methods used together. Here, we constructed a prediction model using the K-nearest neighbors algorithm, one of the machine learning methods, which can predict the sedimentary environments of one core through a known core. Compared to the results of other studies based on the comprehensive data set of grain size and four other indicators, this model achieved a high precision value only using the grain size data. We have also compared our prediction model with other mainstream machine learning algorithms, and the experimental results of six evaluation metrics shed light on that this prediction model can achieve the higher precision. The main errors of the model reflect the length of the conversation area of sedimentary environment, which is controlled by the sedimentary dynamics. This model can provide a quick comparison method of the cores in a similar environment; thus, it may point out the preliminary guidance for further study.

Slip and Fall Characterization of Floors

2004 ◽  
Author(s):  
Peter J. Poczynok ◽  
Ralph L. Barnett
Keyword(s):  
General Theory ◽  
Contact Point ◽  
Force Plate ◽  
Frictional Resistance ◽  
Value Theory ◽  
Reliability Theory ◽  
Duty Cycles ◽  
Time Period ◽  
Five Disciplines

During ambulation, every maneuver causes the feet to impose a tangential loading at each contact with the floor. If the frictional resistance at the contact point is less than the associated tangential loading, slipping occurs and sometimes falling. There are five disciplines, some recently developed, that enable one to develop the general theory for predicting the number of walkers who will slip within a given time period on a statistically homogeneous and isotropic floor. These include force-plate studies, floor duty cycles, tribometry, extreme value theory of slipperiness, and floor reliability theory. When used with some additional bookkeeping notions, the general theory will be extended to real floors traversed by walkers with multiple ambulation styles and wearing a variety of footwear. In contrast, conventional slip and fall theory does not account for floor usage, different footwear and various ambulation styles, nor can it be used to determine the number of walkers who actually slip on a given floor.

scholarly journals Ground Penetrating Radar investigation of depositional architecture: the São Sebastião and Marizal formations in the Cretaceous Tucano Basin (Northeastern Brazil)

2016 ◽  
Vol 46 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Larissa Natsumi Tamura ◽  
Renato Paes de Almeida ◽  
Fabio Taioli ◽  
André Marconato ◽  
Liliane Janikian
Keyword(s):  
Ground Penetrating Radar ◽  
Sedimentary Environment ◽  
Geophysical Methods ◽  
Radar Data ◽  
Northeastern Brazil ◽  
Sedimentary Environments ◽  
Hydrocarbon Reservoir ◽  
Depositional Architecture ◽  
Ground Penetrating ◽  
Radar Facies

ABSTRACT: One key factor for the advance in the study of fluvial deposits is the application of geophysical methods, being the Ground Penetrating Radar one of special value. Although applied to active rivers, the method is not extensively tested on the rock record, bearing interest for hydrocarbon reservoir analogue models. The São Sebastião and Marizal formations were the subject of previous studies, which made possible the comparison of Ground Penetrating Radar survey to previous stratigraphic studies in order to identify the best combination of resolution, penetration and antenna frequency for the studied subject. Eight radar facies were identified, being six of them related to fluvial sedimentary environments, one related to eolian sedimentary environment and one radar facies interpreted as coastal sedimentary environment. The Ground Penetrating Radar data showed compatibility to sedimentary structures in the outcrops, like planar and trough cross-stratified beds. It is noted that the obtained resolution was efficient in the identification of structures up to 0.3 m using a 100 MHz antenna. In this way, the Ground Penetrating Radar survey in outcrops bears great potential for further works on fluvial depositional architecture.

scholarly journals SYNTHESIS AND CHARACTERIZATION OF HYDROXYPROPYL CELLULOSE-CYSTEAMINE CONJUGATE AS A NOVEL CATIONIC THIOMER WITH LIPOPHILIC PROPERTIES

2019 ◽  
Vol 11 (1) ◽  
pp. 222 ◽  
Author(s):  
Deni Rahmat ◽  
Fikry A. R. Rahman ◽  
Liliek Nurhidayati ◽  
Dian Ratih Laksmitawati
Keyword(s):  
Reductive Amination ◽  
Ph Value ◽  
Thiol Group ◽  
Hydroxypropyl Cellulose ◽  
Scanning Calorimetry ◽  
Swelling Behaviour ◽  
Chemically Modified ◽  
Time Period ◽  
Free Thiol Group

Objective: Thiomers have been known as polymer with mucoadhesive properties. The aim of this study was to synthesize the mucoadhesive potential of hydroxypropyl cellulose-cysteamine conjugate (HPC-cysteamine).Methods: The parent polymer HPC was chemically modified by introducing sulphydryl bearing compound using reductive amination. HPC-cysteamine conjugates were prepared at reaction pH value of 5. The reaction was stabilized by the addition of cyanoborohydride. Afterwards, the conjugate was evaluated for optimum free thiol group, swelling behavior, viscosity and mucoadhesive properties.Results: The conjugates showed maximum thiol incorporation on HPC of 1063.03±64.27 µmol/g. The disulphide groups content was 278.71±32.14 μmol/g. Mucoadhesion studies revealed that mucoadhesion of HPC-cysteamine demonstrated 26 h. The swelling behaviour of HPC-cysteamine tablets increased within the time period of study. The viscosity of HPC-cysteamine was higher than that of unmodified HPC. The thermal profile of HPC-cysteamine and unmodified HPC analyzed by differential scanning calorimetry (DSC) displayed a different enthalpy (ΔH) value.Conclusion: HPC-cysteamine conjugate renders better properties which might be more beneficial for drug delivery system compared to unmodified HPC. 

scholarly journals Geochemical Characterization of the Freshwater Faunal Horizons of the Lublin Formation from the Lublin Coal Basin

2017 ◽  
Vol 33 (1) ◽  
pp. 151-162
Author(s):  
Ewa Krzeszowska ◽  
Magdalena Kokowska-Pawłowska
Keyword(s):  
Sedimentary Rock ◽  
Sedimentary Environment ◽  
Coal Basin ◽  
Geochemical Characterization ◽  
Coal Deposits ◽  
Icp Ms

Abstract The most important part of the coal-bearing Carboniferous series is the Lublin formation (Lublin beds) (Westphalian A and B), where the main multi-seam coal deposits occur. Westphalian B is represented by a limnic series with are irregularly formed horizons of freshwater faunal. The paper presents the characteristics of horizons containing the remains of freshwater faunal from the boreholes: Borowo, Syczyn 7, Kulik, Kopina 1 (LCB). These horizons build claystones with layers or clay siderite concretions. For the analyzed horizons the content of the following elements: U, Th, V, Cr, Rb, K (ICP-MS) and oxides: Al2O3, SiO2, P2O5, K2O, MgO, CaO, Na2O, K2O, MnO, TiO2, Cr2O3 (XRF) were determined. The most commonly ratios used in the identification of palaeoenvironment sedimentary were calculated (Th/U, Th/K2O, V/Cr, P2O5/Al2O3, Rb/K). It was found that the content of elements U, Th, V, Cr, Rb K showed very similar values for claystones from borehole: Borowo, Syczyn 7, Kulik, while the sample from borehole Kopina 1 clearly lower value was observed. The research for all samples showed that those ratios such as: U, Th, Th/U, P2O5/Al2O3, V/Cr, Rb/K may be used to identify sedimentary environment and to geochemical correlations of the sedimentary rock sequences in the LCB.

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