Quaternary environmental changes in tropical Lake Towuti, Indonesia, inferred from end‐member modelling of X‐ray fluorescence core‐scanning data

2021 ◽  
Author(s):  
Marina A. Morlock ◽  
Hendrik Vogel ◽  
James M. Russell ◽  
Flavio S. Anselmetti ◽  
Satria Bijaksana
Keyword(s):  
Environmental Changes ◽  
Tropical Lake ◽  
X Ray ◽  
Lake Towuti

Paleoenvironmental reconstruction of the central Levantine Corridor during the Pliocene: insights from lacustrine settings 

2021 ◽  
Author(s):  
John Greenlee ◽  
Silas Dean ◽  
Nicolas Waldmann
Keyword(s):  
High Resolution ◽  
Data Science ◽  
Environmental Changes ◽  
Laser Diffraction ◽  
Climatic Conditions ◽  
Paleoenvironmental Reconstruction ◽  
Cosmogenic Isotopes ◽  
X Ray ◽  
Geochemical Proxies ◽  
Favorable Conditions

<p>This study aims to reconstruct the paleoenvironmental and climatic conditions affecting the Levantine corridor during the early Pliocene. For the purpose of this study, a ~20 m continuous core sequence was retrieved out of the ~200 m long, tilted Erk el Ahmar sequence previously dated by cosmogenic isotopes to ~3.5 Ma. The record include intercalating units consisting of sands, silts, and clays that were sampled in high resolution in order to analyze a variety of sedimentological and geochemical proxies of past climate and environmental changes. We present new preliminary, high-resolution sedimentological (laser diffraction granulometry), petrophysical (magnetic susceptibility) and compositional (X-ray fluorescence) data along with accompanying statistical analysis performed with an advanced suite of data-science tools. These results reveal new cycles of environmental change in the area, which appears to be orbitally controlled, and include dramatic changes also indicated by discrete strata of fossil fragments. Moreover, cycles of deposition can also provide hints on the major hydrological controlling mechanisms. This project provides new light into favorable conditions for the subsistence of perennial lake environments in the Levantine Corridor, which in turn may have facilitated faunal migration between Africa and Eurasia.</p>

scholarly journals Small-Angle X-Ray and Neutron Scattering on Photosynthetic Membranes

2021 ◽  
Vol 9 ◽  
Author(s):  
Dainius Jakubauskas ◽  
Kell Mortensen ◽  
Poul Erik Jensen ◽  
Jacob J. K. Kirkensgaard
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Environmental Changes ◽  
Data Interpretation ◽  
Photosynthetic Membrane ◽  
Noninvasive Methods ◽  
X Ray ◽  
Angle Scattering ◽  
Active Research

Ultrastructural membrane arrangements in living cells and their dynamic remodeling in response to environmental changes remain an area of active research but are also subject to large uncertainty. The use of noninvasive methods such as X-ray and neutron scattering provides an attractive complimentary source of information to direct imaging because in vivo systems can be probed in near-natural conditions. However, without solid underlying structural modeling to properly interpret the indirect information extracted, scattering provides at best qualitative information and at worst direct misinterpretations. Here we review the current state of small-angle scattering applied to photosynthetic membrane systems with particular focus on data interpretation and modeling.

APPLICATIONS OF PIXE ANALYSIS TO STUDIES IN CELL BIOLOGY

1992 ◽  
Vol 02 (03) ◽  
pp. 417-420 ◽  
Author(s):  
SHINJI MATSUMOTO ◽  
MASAKO FURUSE ◽  
KENSUKE KITAO ◽  
TOYOYUKI ISHIHARA ◽  
KUNIHIRO SHIMA ◽  
...  
Keyword(s):  
Cell Biology ◽  
Mammalian Cells ◽  
Environmental Changes ◽  
Molecular Level ◽  
Pixe Analysis ◽  
X Ray ◽  
Preliminary Results ◽  
Linear Relationships ◽  
Element Contents

PIXE application to the measurement of cellular elements is outlined on characteristic variations of the contents of yeast, CHO, V79 and MM46 cultured mammalian cells according to environmental changes. Cellular elements from P to Br were successfully analyzed at these cells after cautious preparation of samples in filtration steps with as possible as less deterioration. We confirmed linear relationships between the X-ray yields and these element contents. The experiment was extended to an analysis of cellular substances at molecular level by scanning of specimens. Preliminary results were included.

scholarly journals Comparative Compressibility of Smectite Group under Anhydrous and Hydrous Environments

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3784
Author(s):  
Yongmoon Lee ◽  
Pyosang Kim ◽  
Hyeonsu Kim ◽  
Donghoon Seoung
Keyword(s):  
High Pressure ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Environmental Changes ◽  
Silicone Oil ◽  
Distilled Water ◽  
X Ray ◽  
Water Conditions ◽  
Before And After ◽  
Cell Volumes

High-pressure synchrotron X-ray powder diffraction studies of smectite group minerals (beidellite, montmorillonite, and nontronite) reveal comparative volumetric changes in the presence of different fluids, as pressure transmitting media (PTM) of silicone oil and distilled water for anhydrous and hydrous environments at room temperature. Using silicone oil PTM, all minerals show gradual contraction of unit-cell volumes and atomistic interplane distances. They, however, show abrupt collapse near 1.0 GPa under distilled water conditions due to hydrostatic to quasi-hydrostatic environmental changes of water PTM around samples concomitant with the transition from liquid to ICE-VI and ICE-VII. The degrees of volume contractions of beidellite, montmorillonite, and nontronite up to ca. 3 GPa are ca. 6.6%, 8.9%, and 7.5% with bulk moduli of ca. 38(1) GPa, 31(2) GPa, and 26(1) GPa under silicone oil pressure, whereas 13(1) GPa, 13(2) GPa, and 17(2) GPa, and 17(1) GPa, 20(1) GPa, and 21(1) GPa under hydrostatic and quasi-hydrostatic environments before and after 1.50 GPa, respectively.

scholarly journals Occurrences and genesis of palygorskite/sepiolite and associated minerals in the Barzaman formation, United Arab Emirates

Clay Minerals ◽  
2016 ◽  
Vol 51 (5) ◽  
pp. 763-779 ◽  
Author(s):  
Salah Draidia ◽  
Meriam El Ouahabi ◽  
Lahcen Daoudi ◽  
Hans-Balder Havenith ◽  
Nathalie Fagel
Keyword(s):  
United Arab Emirates ◽  
Environmental Changes ◽  
Drill Hole ◽  
Silty Clay ◽  
X Ray Diffraction ◽  
Humid Climate ◽  
Western Margin ◽  
X Ray ◽  
Direct Precipitation ◽  
Scanning Electron

AbstractThe Barzaman Formation exposed in the United Arab Emirates was deposited as a series of fluvial sediment sequences lying along the western margin of the Hajar Mountains, part of the Oman–UAE ophiolite. This formation consists of a sequence of rocks dominated by variably cemented and altered conglomerates comprising calcareous siltstones and calcareous clays deposited during the Miocene to Pliocene under a humid climate. The conglomerates are composed largely of ultramafic and lesser-mafic clasts. The present study was undertaken in order to understand the occurrence and genesis of palygorskite and sepiolite in relation to the environmental changes including evaporitic and sabkha environments.Sediments were collected from two trenches and a drill hole of ∼22 m depth. Samples were analysed by optical petrograpy, X-ray diffraction and scanning electron microscopy. Pedogenesis occurred at the deeper level in well cemented conglomerate which constitutes the hard crust. Post-depositional erosion started in marine phreatic or vadose zones as shown by the neoformation of serpentine from the weathering of olivine as well as of calcite and dolomite. Neoformation of palygorskite, sepiolite, dolomite and halite occurred under evaporitic conditions on calcareous silty clay facies. Relatively hot, vadose and oxidizing environmental conditions affected the calcareous siltstone facies leading to the genesis of dolomite and palygorskite by direct precipitation from solution rich in Ca, Mg, Al, Fe and Si ions.

Environmental changes in a tropical lake (Lake Abiyata, Ethiopia) during recent centuries

2002 ◽  
Vol 187 (3-4) ◽  
pp. 233-258 ◽  
Author(s):  
Dagnachew Legesse ◽  
F Gasse ◽  
O Radakovitch ◽  
C Vallet-Coulomb ◽  
R Bonnefille ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Tropical Lake

scholarly journals Elemental Analysis on Marine Sediments Related to Depositional Environment of Bangka Strait

2018 ◽  
Vol 32 (2) ◽  
Author(s):  
Pungky Sampurno ◽  
Rina Zuraida ◽  
Nazar Nurdin ◽  
Luli Gustiantini ◽  
Noor Cahyo Dwi Aryanto
Keyword(s):  
Magnetic Susceptibility ◽  
Elemental Composition ◽  
Elemental Analysis ◽  
Depositional Environment ◽  
Environmental Changes ◽  
Sediment Cores ◽  
X Ray ◽  
Scatter Plots ◽  
Group 2 ◽  
Non Destructive

Study of elemental composition in sediment has been proven useful in interpreting the depositional environmental changes. Multi Sensor Core Logger (MSCL) is a non-destructive analysis that measures several parameters in sediment core including magnetic susceptibility and elemental composition. Magnetic susceptibility and elemental analysis were measured in four selected marine sediment cores from western part of Bangka Strait (MBB-67. MBB-119, MBB-120 and MBB-173) by using magnetic susceptibility and X-ray Fluorescence (XRF) sensors attached to the MSCL. The data was collected within 2 cm interval. Scatter plots of Y/Zr and Zr/Ti show singular trend demonstrated by sediments from MBB-173 and two groups that composed of MBB-67 (Group 1) and MBB-119 + MBB-120 (Group 2). MBB-67 that is located adjacent to Klabat Granite shows upward changes in mineralogy, slight increase of grain size and negligible change in Y concentration. Cores MBB-119 and MBB-120 are inferred to be deposited during regression that resulted in the accummulation of Y-bearing zircon in MBB-119 before the mineral could reach MBB-120. Core MBB-173 is interpreted to be the product of plagioclase weathering that is submerged by rising sea level. This core contains a horizon of rich Y-bearing zircon at 60 cm.Keywords: Multi Sensor Core Logger, X-Ray Fluorescence, magnetic susceptibility, depositional environment, Bangka Island Studi tentang komposisi unsur kimia dalam sedimen telah terbukti bermanfaat dalam interpretasi perubahan lingkungan pengendapan. Multi Sensor Core Logger (MSCL) adalah sebuah analisis yang non-destructive, untuk mengukur beberapa parameter dalam bor sedimen termasuk suseptibilitas magnetik dan kandungan unsur. Suseptibilitas magnetik dan kandungan unsur diukur dari 4 bor sedimen laut yang terpilih di bagian barat Selat Bangka (MBB-67. MBB-119, MBB-120 and MBB-173) dengan menggunakan sensor suseptibilitas magnetik (MS) dan X-ray Fluorescence (XRF) yang terpasang pada MSCL. Pengukuran dilaksanakan dengan interval 2 cm. Plot Y/Zr dan Zr/Ti menunjukkan satu trend yang diperlihatkan oleh sedimen bor MBB-173 dan dua grup yang terdiri atas MBB-67 (Grup 1) dan MBB-119 + MBB-120 (Grup 2). Bor MBB-173 ditafsirkan sebagai hasil pelapukan plagioklas yang kemudian terendam air laut. Bor ini memperlihatkan horizon yang kaya akan zirkon pembawa yttrium pada kedalaman 60 cm.Kata kunci : Multi Sensor Core Logger, X-Ray Fluorescence, suseptibilitas magnetik, lingkungan pengendapan, Pulau Bangka

scholarly journals ABNORMAL MICROFAUNAL SHELLS AS EARLY WARNING INDICATOR OF ENVIRONMENTAL CHANGES SURROUNDING BERAU DELTA, EAST KALIMANTAN

2016 ◽  
Vol 26 (1) ◽  
pp. 31
Author(s):  
Kresna Tri Dewi ◽  
Yusuf Adam Priohandono
Keyword(s):  
Chemical Composition ◽  
Early Warning ◽  
Environmental Changes ◽  
Mine Drainage ◽  
Combustion Process ◽  
Coal Ash ◽  
Energy Dispersive ◽  
X Ray ◽  
Early Warning Indicator ◽  
East Kalimantan

A total of 25 sediment samples from surrounding Berau Delta, East Kalimantan have been used for microfaunal study. It is found some abnormal shells of ostracoda, foraminifera and other forms with darkish shells (black, dark green and dark brown). These forms were analyzed using SEM-Energy Dispersive X-ray spectroscopy (EDX or EDS) to know their chemical composition. The result shows that these abnormal forms composed of CaO, SiO2, C, FeO, Al2O3, K2O, and small amount of Na2O and Cl. They may derive from different sources: CaO and MgO from neutralized component during the environmental management to handle the Acid Mine Drainage (AMD). The other components may derive from coal ash during combustion process or other activities. From this result, the small amount (less than 5%) of abnormal shells may be used as early warning indicator of environmental changes in the study area. Keywords: abnormal microfaunal shells, chemical composition, Berau Delta. Sebanyak 25 sampel sedimen dari sekitar Delta Berau, Kalimantan Timur telah digunakan untuk studi mikrofauna. Ditemukan cangkang abnormal dari ostracoda, foraminifera dan spesimen bentuk lain dengan cangkang kegelapan (hitam, hijau tua dan coklat tua) Bentuk-bentuk ini kemudian dianalisa menggunakan SEM-Energy Dispersive X-ray spectroscopy (EDX or EDS) untuk mengetahui komposisi kimiawinya. Hasilnya menunjukkan bahwa cangkang-cangkang mikrofauna yang abnormal ini mengandung CaO, SiO2, C, FeO, Al2O3, K2O, dan sedikit kandungan Na2O dan Cl. Komponen ini kemungkinan mempunyai sumber yang berbeda: CaO dan MgO mungkin berasal dari bahan penetral selama pengelolaan lingkungan untuk mengatasi air asam tambang (AMD). Komponen lain berasal dari abu batubara saat proses pembakaran atau aktivitas lain. Jumlah cangkang abnormal yang sedikit (kurang dari 5%) ini kemungkinan dapat digunakan sebagai indikator peringatan dini adanya perubahan lingkungan di daerah penelitian. Kata kunci: cangkang mikrofauna abnormal, komposisi kimiawi, Delta Berau

Stromatolite Growth in Lagoa Vermelha, Southeastern Coast of Brazil: Evidence of Environmental Changes

Radiocarbon ◽  
2017 ◽  
Vol 60 (2) ◽  
pp. 383-393 ◽  
Author(s):  
Carla Carvalho ◽  
Maria Isabela N. Oliveira ◽  
Kita Macario ◽  
Renato B. Guimarães ◽  
Carolina N Keim ◽  
...  
Keyword(s):  
Growth Rates ◽  
Environmental Changes ◽  
Arid Environment ◽  
High Availability ◽  
Water Evaporation ◽  
X Ray Diffraction ◽  
Lower Growth ◽  
X Ray ◽  
Hypersaline Lagoon ◽  
Dolomite Formation

AbstractAmong the oldest remains of living beings to have inhabited the Earth’s surface, there are the stromatolites—laminated sedimentary rocks associated with lithified mats of layered phototrophic microbial communities—which grow in specific environmental conditions. In the present work, we study a recent carbonatic stromatolite from Lagoa Vermelha (Rio de Janeiro, Brazil), a shallow coastal hypersaline lagoon. X-ray diffraction was associated to a depth chronological model defining three different sections based on changes in mineral composition of the stromatolite with increased dolomite content. Although a mean growth rate of 0.19±0.03 mm/yr is observed, the model discloses decreasing growth rates among the sections. Since dolomite formation can be related to high availability of Mg+2, confirmed by an expressive presence of (Ca, Mg)CO3, the lower growth rates were associated to a more arid environment, until approximately 1440 cal AD, with higher temperatures and consequently promoting water evaporation and salinity enhancement.

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