scholarly journals Hazardous radioactivity levels and heavy mineral concentrations in beach sediments of Lake Peipsi, northeastern Estonia

Geologos ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 1-12
Author(s):  
Johanna-Iisebel Järvelill ◽  
Rein Koch ◽  
Anto Raukas ◽  
Tiit Vaasma
Keyword(s):  
Mineral Content ◽  
Heavy Mineral ◽  
Western Coast ◽  
Northern Coast ◽  
Quaternary Sediments ◽  
Lake Peipsi ◽  
Beach Sediments ◽  
Mineral Concentrations ◽  
Mineral Analyses ◽  
Radioactivity Levels

Abstract The present study discusses results of heavy mineral analyses and radioactivity of beach sediments of Lake Peipsi. Such analyses are commonly done globally, but had not yet been conducted for the fourth largest lake in Europe. The average heavy mineral content in Lake Peipsi beach sediments along the northern and western coast is higher than usual for Estonian coastal and Quaternary sediments. Concomitantly, elevated radioactivity levels have been measured in several places, with the highest concentrations observed at Alajõe (1885.5 Bq/kg), which is over five times more than the recommended limit. The aim of the present study is to find sites with higher radioactivity levels, because the northern coast of Lake Peipsi is a well-known recreational area.

Recognition of a Cretaceous outlier in northwestern Ontario

1990 ◽  
Vol 27 (2) ◽  
pp. 306-311 ◽  
Author(s):  
Pierre A. Zippi ◽  
Andrew F. Bajc
Keyword(s):  
Heavy Mineral ◽  
Quaternary Sediments ◽  
Northwestern Ontario ◽  
Clastic Sediments ◽  
Angiosperm Pollen ◽  
Mineral Analyses

Borehole F-88-33, located near Rainy River, Ontario, intersected Cretaceous nonmarine clastic sediments. This is the first documented occurrence in Ontario of Cretaceous sediments associated with the western interior. Lithologie and heavy-mineral analyses were used to differentiate this unit from the overlying Quaternary sediments. Seventy-five species of fossil angiosperm pollen, gymnosperm pollen, spores, megaspores, and algal cysts were recovered from borehole F-88-33 and used to date the pre-Quaternary sediments as late Albian to early Cenomanian. The occurrence of these nonmarine sediments in northwestern Ontario helps to better define the limits of Cretaceous sedimentation in the western interior.

scholarly journals Heavy mineral distribution in Weichselian drift successions in eastern Denmark

1981 ◽  
Vol 30 ◽  
pp. 1-10
Author(s):  
Lise Holm
Keyword(s):  
Mineral Content ◽  
Heavy Mineral ◽  
Published Data ◽  
Mineral Distribution ◽  
Source Areas ◽  
Opaque Mineral ◽  
Representative Samples ◽  
Mineral Analyses

The use of heavy mineral content in Weichselian drift units as a stratigraphic tool has been investigated. A total of 26 heavy mineral analyses of representative samples frorn the four Weichselian kineto­stratigraphic units in eastern Denmark are presented with data on both non-opaque and opaque mineral content. The heavy mineral content frorn inferred source areas has been deduced, partly from published data and partly from studies carried out by the author. The data indicate that heavy mineral analyses cannot be used as a general stratigraphic tool. However, the heavy mineral distribution indicates the occurrence of two distinct Weichselian heavy mineral provinces, a northern and a southern. The reasons why clast petrography studies may supply more reliable stratigraphic information are discussed.

Heavy minerals in stream sediments from Churchill Falls, Labrador—an aid in bedrock mapping

1980 ◽  
Vol 17 (2) ◽  
pp. 244-253
Author(s):  
John Edward Callahan
Keyword(s):  
Frequency Distribution ◽  
Mineral Content ◽  
Regional Metamorphism ◽  
Stream Sediments ◽  
Heavy Mineral ◽  
Heavy Minerals ◽  
Sediment Samples ◽  
Fluvial Deposits ◽  
Geologic Map ◽  
High Concentrations

Stream sediments from a 13 000 km2 previously glaciated area in central Labrador near Churchill Falls were examined for their heavy mineral content. The minus 0.25 mm (60 mesh) nonmagnetic heavy mineral fraction from 846 stream sediment samples consists mainly of magnetite, ilmenite. garnet, hornblende, epidote and minor clinopyroxene, orthopyroxene. kyanite. sillimanite, biotite. apatite, and zircon. Changes in the frequency distribution of epidote, hornblende, garnet, and sillimanite in the stream sediments correspond well with those reported in previously mapped underlying bedrock lithologies. The occurrence of kyanite and sillimanite, high concentrations of garnet and opaques (mainly ilmenite), and lower concentrations of hornblende and epidote were used to determine grades of regional metamorphism, resulting in revision of the geologic map of this area. Heavy minerals in glacial drift or fluvial deposits may be useful as an aid in mapping in glaciated areas.

scholarly journals THE IMPACT OF SEASONAL CHANGES ON HEAVY MINERALS CONCENTRATION FROM A PART OF EAST COAST OF INDIA

2020 ◽  
Vol 5 (1) ◽  
pp. 12-21
Author(s):  
Ali Mohammad ◽  
E.N. Dhanamjayarao
Keyword(s):  
Seasonal Changes ◽  
East Coast ◽  
Heavy Mineral ◽  
Heavy Minerals ◽  
Sediment Characteristics ◽  
Seasonal Fluctuations ◽  
Post Monsoon ◽  
Seasonal Circulation ◽  
Mineral Concentrations ◽  
The Impact

Pre and post monsoonal changes in the environment have led to a noticeable variation in sediment characteristics, heavy mineral concentrations and their distribution. The current study aimed to find out the effect of seasonal fluctuations on the concentration of heavy minerals along the coast and the variations in sediment textures and distribution. The study has revealed the effect of seasons on the sediments supply and its distribution along coast in the study area. The total heavy minerals concentrations are more in post monsoon than in pre monsoon and the concentration also increases from south to north in parts of the study area because of seasonal circulation of currents from south to north along the shore. The micro textural study of the heavy mineral grains from different locations in the study area revealed the mechanical and chemical erosions on the grain surfaces.

The effect of variation in dietary protein concentration and energy intake on mineral accretion in early-weaned lambs

1981 ◽  
Vol 96 (3) ◽  
pp. 557-560 ◽  
Author(s):  
J. Davidson ◽  
I. McDonald
Keyword(s):  
Energy Intake ◽  
Dietary Protein ◽  
Protein Concentration ◽  
Calcium Concentration ◽  
Mineral Content ◽  
Calcium And Phosphorus ◽  
Rates Of Growth ◽  
Mineral Analyses

SUMMARYMineral analyses for calcium and phosphorus were carried out on lambs which had been fed diets contrasting in protein or energy or calcium concentration and had been slaughtered at defined live weights. Despite considerable variation in rates of growth arising from the widely different nutritional programmes, the mineral content of these lambs at a given weight remained remarkably stable on practical diets.

Partial repression of siderophore-mediated iron transport in Azotobacter vinelandii grown with mineral iron

1988 ◽  
Vol 34 (5) ◽  
pp. 675-679 ◽  
Author(s):  
William J. Page ◽  
Gregory A. Grant
Keyword(s):  
Molecular Weight ◽  
Outer Membrane ◽  
Iron Transport ◽  
Mineral Content ◽  
Azotobacter Vinelandii ◽  
Outer Membrane Proteins ◽  
Additional Component ◽  
Transport Activity ◽  
Fe Uptake ◽  
Mineral Concentrations

Azotobacter vinelandii grown in iron-limited medium containing increased amounts of the minerals olivine or glauconite produced decreased amounts of siderophores and iron-repressible outer membrane proteins. These minerals caused a relatively rapid repression of the pyoverdin-type siderophore, azotobactin, and a slower repression of the catechol siderophores, azotochelin and aminochelin. A 77 000 molecular weight outer membrane protein also was repressed with increased mineral content of the medium, but coordinate repression with any one siderophore was not evident. Cells grown with increased mineral concentrations progressively lost siderophore-mediated iron-transport activity. This loss in activity had the greatest effect on azotobactin-mediated 55Fe uptake, but catechol siderophore mediated 55Fe uptake also was depressed. These results suggested that an additional component was required for maximal iron-transport activity promoted by all the siderophores of A. vinelandii.

Sign in / Sign up

Export Citation Format

Share Document