A study on the distribution of free iron and manganese oxides was conducted in soils developed on calcareous alluvial deposits under subhumid climatic conditions, in Western Greece. Soil samples from two well drained ...A study on the distribution of free iron and manganese oxides was conducted in soils developed on calcareous alluvial deposits under subhumid climatic conditions, in Western Greece. Soil samples from two well drained soils and from two poorly drained soils, classified as Alfisols, were collected and used in this study. After certification of soil homogeneity the acid ammonium oxalate and dithionite-citrate-bicarbonate methods were used to extract free iron and manganese oxides from the samples. Iron oxides extracted by the dithionite-citrate-bicarbonate method (Fed) were significantly higher than the iron oxides extracted by the ammonium oxalate method (Feo), indicating that a considerable fraction is present in crystalline forms,independent of drainage status. A confirmation of free iron oxides and fine clay was detected. The ratios Feo/Fed and (Fed-Feo)/total Fe (Fet) could not be used to distinguish the well drained soils from the poorly drained soils. Manganese movement in a soluble form is independent of the fine clay.展开更多
Sedimentological methods such as granulometry, morphoscopy and heavy minerals analysis have been carried out to characterize alluvial gold deposits of Betare-Oya and its surroundings, with the aim to determine their o...Sedimentological methods such as granulometry, morphoscopy and heavy minerals analysis have been carried out to characterize alluvial gold deposits of Betare-Oya and its surroundings, with the aim to determine their origin and conditions in which they are formed and also to determine the mineralogical content of these deposits, their nature and distribution. It came out from this study the following: The alluvial deposits studied are sand, constituting of coarse fraction (grains), medium grains in abundant and fine grains. The average values of sorting index (S0) and coefficient of asymmetry (A) are respectively 2.53 and 0.73. These values indicate that the sand is poorly arranged and poorly sorted with a better classification or arrangement in the coarse fraction (grains). These are sediments that are deposited together by high competent currents. It would therefore probably be torrential deposits and or streams from short transport. Unused grains are dominating (80.5%) which translate a proximal source of the sediments. So it would be probably from the dismantling of the surrounding landforms. The heavy minerals studied revealed the presence of the following minerals;zircon, gold, sphene, green hornblende, tourmaline, rutile, augite, hypersthene, sillimanite, glau-cophane, biotite, staurotide, and the opaque. These minerals belong to the cortege of plutonic and metamorphic rocks from a single proximal distributing province.展开更多
Vranic site is a sand quarry that is located on the southern foothills of Papuk Mountain.From bottom to top of the succession,three sedimentary units have been recognized as:Unit 1 containing massive sand with scatter...Vranic site is a sand quarry that is located on the southern foothills of Papuk Mountain.From bottom to top of the succession,three sedimentary units have been recognized as:Unit 1 containing massive sand with scattered gravel-sized clasts,marl cobbles and boulders,and abundant marine mammal and fish fossils;Unit 2 consisting of sand intercalated with silt,clay and gravel,which may be horizontally bedded;and Unit 3,which is an erosionally-based lenticular matrix to clast-supported structureless gravel.The basal part of Unit 1 shows numerous reworked skeletal remains of Miocene marine mammals.Cosmogenic radionuclides constrain the age of burial of Unit 1 to 895±211 ka,while the source area of Unit 1 had a quick denudation.The massive sands deposited on the slopes of Papuk Mountain were vulnerable to erosion due to the absence of clay.Heavy rainfall or water from snow melting created flash floods that infiltrated the sands,thereby causing slope destabilization and deformation.This process led to slumps that were transformed into a sandy debris flow.This sediment was probably deposited during the interglacial marine isotope age(MIS)21 period when the scarce vegetation and a warmer climate favored the melting of permafrost ice and consequently triggered slope movements during MIS 22.The reworked skeletal material sampled at the Vranic site comprises fossilized fish along with mammal bones and teeth.Thus,the Vranic site represents an important site for cetacean fossil remains and serves as an important data source for marine life in the Central Paratethys.展开更多
文摘A study on the distribution of free iron and manganese oxides was conducted in soils developed on calcareous alluvial deposits under subhumid climatic conditions, in Western Greece. Soil samples from two well drained soils and from two poorly drained soils, classified as Alfisols, were collected and used in this study. After certification of soil homogeneity the acid ammonium oxalate and dithionite-citrate-bicarbonate methods were used to extract free iron and manganese oxides from the samples. Iron oxides extracted by the dithionite-citrate-bicarbonate method (Fed) were significantly higher than the iron oxides extracted by the ammonium oxalate method (Feo), indicating that a considerable fraction is present in crystalline forms,independent of drainage status. A confirmation of free iron oxides and fine clay was detected. The ratios Feo/Fed and (Fed-Feo)/total Fe (Fet) could not be used to distinguish the well drained soils from the poorly drained soils. Manganese movement in a soluble form is independent of the fine clay.
文摘Sedimentological methods such as granulometry, morphoscopy and heavy minerals analysis have been carried out to characterize alluvial gold deposits of Betare-Oya and its surroundings, with the aim to determine their origin and conditions in which they are formed and also to determine the mineralogical content of these deposits, their nature and distribution. It came out from this study the following: The alluvial deposits studied are sand, constituting of coarse fraction (grains), medium grains in abundant and fine grains. The average values of sorting index (S0) and coefficient of asymmetry (A) are respectively 2.53 and 0.73. These values indicate that the sand is poorly arranged and poorly sorted with a better classification or arrangement in the coarse fraction (grains). These are sediments that are deposited together by high competent currents. It would therefore probably be torrential deposits and or streams from short transport. Unused grains are dominating (80.5%) which translate a proximal source of the sediments. So it would be probably from the dismantling of the surrounding landforms. The heavy minerals studied revealed the presence of the following minerals;zircon, gold, sphene, green hornblende, tourmaline, rutile, augite, hypersthene, sillimanite, glau-cophane, biotite, staurotide, and the opaque. These minerals belong to the cortege of plutonic and metamorphic rocks from a single proximal distributing province.
基金supported by Projects no.181-18110961093 of the Croatian Ministry of ScienceEducation and Sports and by the project NKFIH 124807 of the National Research,Development and Innovation Office of Hungary+1 种基金The measurements performed at ASTER(CEREGE,Aix-en-Provence,France)were supported by the INSU/CNRS,the French Ministry of Research and Higher Education,IRD and CEAAMS measurements performed at VERA were supported by the RADIATE project 19001688-ST under the Grant Agreement 824096 from the EU Research and Innovation programme HORIZON 2020.
文摘Vranic site is a sand quarry that is located on the southern foothills of Papuk Mountain.From bottom to top of the succession,three sedimentary units have been recognized as:Unit 1 containing massive sand with scattered gravel-sized clasts,marl cobbles and boulders,and abundant marine mammal and fish fossils;Unit 2 consisting of sand intercalated with silt,clay and gravel,which may be horizontally bedded;and Unit 3,which is an erosionally-based lenticular matrix to clast-supported structureless gravel.The basal part of Unit 1 shows numerous reworked skeletal remains of Miocene marine mammals.Cosmogenic radionuclides constrain the age of burial of Unit 1 to 895±211 ka,while the source area of Unit 1 had a quick denudation.The massive sands deposited on the slopes of Papuk Mountain were vulnerable to erosion due to the absence of clay.Heavy rainfall or water from snow melting created flash floods that infiltrated the sands,thereby causing slope destabilization and deformation.This process led to slumps that were transformed into a sandy debris flow.This sediment was probably deposited during the interglacial marine isotope age(MIS)21 period when the scarce vegetation and a warmer climate favored the melting of permafrost ice and consequently triggered slope movements during MIS 22.The reworked skeletal material sampled at the Vranic site comprises fossilized fish along with mammal bones and teeth.Thus,the Vranic site represents an important site for cetacean fossil remains and serves as an important data source for marine life in the Central Paratethys.
