scholarly journals GENESIS AND PHYSICAL CHARACTERISTICS OF THE NEOGENE RED BEDS FROM THE CEDARHILS OF THESSALONIKI, MACEDONIA , GREECE

2018 ◽  
Vol 36 (2) ◽  
pp. 708 ◽  
Author(s):  
A. Tsirambides
Keyword(s):  
Clay Minerals ◽  
Urban Forest ◽  
Clay Fraction ◽  
Eastern Mediterranean Region ◽  
Physical Characteristics ◽  
Coarse Grained ◽  
Red Beds ◽  
Primary Minerals ◽  
In Situ Weathering

The genesis and the physical characteristics of the Neogene red beds of the cedar hills surrounding Thessaloniki are studied in this paper. The peri-urban forest, which covers these hills, has a 3,022 ha area. The topographic relief is smooth and is divided in eight small drainage basins, tapped through small creeks. The elevation of the surrounding hills varies between 85 and 560 m. The dominant land slopes vary between 20 and 55%. All the samples are coarse grained, poorly sorted and friable and present earthy lustre and red colour because of the extensive presence of iron oxides. Angular to sub-angular rock fragments derived from the metamorphic bedrock are very common. Petrographically, the studied red beds belong to the clayey sands. The extended presence (41-66%) of coarse silt and sand size grains (>20 pm) in the samples suggests a mild intensity of in situ weathering of the bedrock. X-ray diffraction analysis of the coarsest fractions 250-20 pm and 20-2 μιτι revealed in decreasing abundance the presence of quartz, feldspars, epidote, micas, chlorite, pyroxenes, amphiboles, and talc. These fractions contain the 2M polytype of mica, while in the fraction <2 pm the 1Μα polytype of illite predominates. In the clay fraction (<2 pm) illite, smectite, and chlorite predominate. The presence of mixed-layer minerals is limited, testifying the almost complete character of hydrolysis of the primary minerals. The formation of red beds took place on low relief land under alternating wet and dry seasons, which prevail in the eastern Mediterranean region since Neogene. The clay minerals are the in situ weathering products of the primary minerals of the greenschists, gneisses and gabbros predominating in the studied area. The extensive presence of clay size grains (11-26%) in the samples, their poor sorting, and their sub-angular morphology, indicate that the red beds are texturally immature. In addition, the abundance of feldspars and Fe-Mg minerals reflects mineralogical immaturity. The low relief and the long-lasting tectonic stability in the Thessaloniki district were essential for the significant thickness of the red beds. The oxygen isotope data of the <0.2 pm fraction (+18.2 to +18.8%o) confirm the pedogenic origin of the clay minerals present. The red beds studied present low plasticity with liquid limit (WÏ) 26.9 to 33.4% and plasticity index (lp) 9.1 to 17.3%. In addition, they have high consolidation index (lc) values (1.03 to 2.28). The swelling potential is low to medium and the activity varies between 0.5 and 1.0. The consolidation and induration degree of the samples analyzed is low, because of the great range of their mineralogical composition and the mild conditions of pressure and temperature to which they have been submitted. The studied red beds are not considered problematic for the foundation of various constructions on them.

Paleoweathered surfaces on granitoids of southern Nova Scotia: paleoenvironmental implications of saprolites

2003 ◽  
Vol 40 (6) ◽  
pp. 805-817 ◽  
Author(s):  
Anne Marie O'Beirne-Ryan ◽  
Marcos Zentilli
Keyword(s):  
Nova Scotia ◽  
Clay Minerals ◽  
Silica Sand ◽  
South Mountain Batholith ◽  
History Of ◽  
And Migration ◽  
Clastic Sedimentary ◽  
Weathering Effects ◽  
In Situ Weathering

In addition to minor postglacial weathering effects, a complex history of three distinct weathering events has been identified within the granitoids of the South Mountain Batholith of southwestern Nova Scotia. Weathering prior to deposition of Carboniferous strata produced a well-developed saprolite, an in situ weathering profile. Feldspars and micas are altered to clay minerals, and only weak preservation of granitic texture is evident. Subsequent burial and relithification have masked the original weathering mineralogy in this horizon. Beneath Triassic clastic sedimentary rocks is a thick horizon (30 m) of weathered granitoid. This argillaceous saprolite with relict biotite exhibits an intensifying-upward weathering zonation typical of weathered horizons, with increased proportions of clay minerals at the upper levels. A younger arenaceous saprolite of pre-Pleistocene age can be found beneath glacial till at a number of locations throughout the batholith. These paleoweathered horizons attest to relatively warmer climates at several times in the geologic past. Their patterns of preservation imply some were much thicker and more widely distributed before partial erosion. The eroded materials may have formed the sediment for quartz sand in the Carboniferous sequence, clay and silica sand deposits of Cretaceous age, and a sandy till of Pleistocene age. The remnants preserved in situ today serve as significant conduits for water, and the geochemistry, mineralogy, and textures of these weathered profiles may enhance mobility and migration of U and Rn. These weathered horizons are mechanically weak, and the possibility of their presence should be considered when selecting construction and waste-disposal sites.

Some aspects of the genesis of an alpine humus soil

Soil Research ◽  
1973 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
R Brewer ◽  
AD Haldane
Keyword(s):  
Sudden Change ◽  
Clay Fraction ◽  
Clay Mineralogy ◽  
Soil Formation ◽  
Mineral Weathering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Humus Soil ◽  
In Situ Weathering

An alpine humus soil profile has been examined in the field, in thin section and by X-ray diffraction. The presence of a stone line and the sudden change in characteristics across the stone line, including particle size distribution, degree of exfoliation of the micas, major mineral composition, and clay mineralogy suggest that this is a polygenetic profile consisting of two soil stratigraphic units. There has been little pedological reorganization within either unit, soil formation consisting essentially of in situ weathering, removal of soluble constituents, and accumulation of organic matter, with some biological activity, in the upper unit. It is shown that gibbsite derived from weathering of feldspar is a major component of the clay fraction, especially in the lower unit. The clay mineralogy is considered in relation to proposed mineral weathering sequences and weathering in a yellow podzolic soil.

Micromorphology and mineralogy of a layered red-brown earth profile

Soil Research ◽  
1975 ◽  
Vol 13 (2) ◽  
pp. 101 ◽  
Author(s):  
JR Sleeman
Keyword(s):  
Surface Layer ◽  
Iron Oxides ◽  
Manganese Oxides ◽  
Lower Layer ◽  
Clay Fraction ◽  
Clay Mineralogy ◽  
Parent Material ◽  
The Third ◽  
In Situ Weathering

The micromorphology and non-clay mineralogy of a red-brown earth profile from Pyramid Hill, Vic., have been examined in order to test Butler's postulated genesis based on field criteria. The profile includes four separate parent material layers. The lowest layer appears to have been derived mainly from in situ weathering of granite. The upper three layers have been derived mainly from a source other than the local granite and have microscopic characteristics comparable to those of altered parna, viz. a non-clay fraction which shows a marked peak in the 30-60 �m range, which consists of quartz and felspar with magnetite, ilmenite, leucoxene and titanite and which has a zircon/tourmaline ratio of about 0.5. As well as a solum developed in the upper two parna layers, there appears to be a buried truncated soil associated with the third parna layer. In both soils there has been significant translocation and deposition of carbonates, iron oxides and hydroxides, manganese oxides and hydroxides and clay, with somewhat more material segregated in the lower solum. Weathering and water-table effects at some depth below a prior surface appear to have been responsible for segregations within the lower layer derived from granite. The data support the concepts of Butler, and in addition indicate contamination of the surface layer by reasonably fresh minerals.

scholarly journals Texture and mineralogical composition of Quaternary terrestrial and marine sediments from Macedonia and Thrace, Greece

2019 ◽  
Vol 55 (1) ◽  
pp. 137
Author(s):  
Ananias Tsirambides
Keyword(s):  
Clay Minerals ◽  
Clay Fraction ◽  
Mineralogical Composition ◽  
Climatic Conditions ◽  
Coarse Grained ◽  
Quartz Content ◽  
Fine Grained ◽  
Weathering Processes ◽  
The North ◽  
Interstratified Phase

Clastic sediments collected from land and gulfs of Macedonia and Thrace in Greece are examined on the basis of their texture and mineral composition. All terrestrial samples are coarse-grained and poorly sorted, with angular to sub-angular grains. These are mainly composed of quartz and feldspars, followed by micas, calcite and Fe-Mg minerals. Among the clay minerals illite predominates over smectite and smectite over vermiculite (+chlorite+kaolinite). In addition, the interstratified phases illite/smectite, chlorite/vermiculite, and smectite/vermiculite are present in significant amounts in the clay fraction (<2 μm), signifying the incomplete weathering of the primary minerals. Mixing during transportation, flocculation, differential settling processes and organic matter are the main mechanisms for the distribution of the discharged terrigenous load into the North Aegean Gulfs. All gulf bottom samples are coarse to fine grained and medium sorted, and their grains are angular to sub-angular. Quartz and feldspars predominate. In addition, biogenic calcite, micas and various Fe-Mg minerals exist as primary and/or accessory minerals. Among clay minerals, illite predominates over smectite and smectite over kaolinite (+chlorite+vermiculite). Almost in all gulf sediments the interstratified phase illite/smectite is apparent. The presence of feldspars and Fe-Mg minerals, as well as the high content of clay minerals and the polymodal grain-size distribution with angular to sub-angular grains, signify mineralogical and textural immaturity of all the examined sediments, as well as predominance of mild climatic conditions and thus mild weathering processes. The quartz content in these sediments is usually <70%. Therefore, a sedimentation cycle of these materials has not been completed.

Significance of The Sedimentology and Stratigraphy for Identification of Low Contras Low Resistivity zones in a Clastic Outcrop of The Upper Talang Akar Formation, Musi Banyuasin, Indonesia

2021 ◽  
Author(s):  
A. F. H. Surbakti
Keyword(s):  
Clay Minerals ◽  
Coarse Grained ◽  
The South ◽  
Reservoir Properties ◽  
Low Contrast ◽  
Facies Distribution ◽  
Low Resistivity ◽  
Different Sources

The Talang Akar Formation is one of the hydrocarbon-producing reservoirs of the South Sumatra Basin. This basin is filled from two different sources in the Eastern part and Western part paleo-high. The bottom Talang Akar consists of coarse-grained sandstone, and the upper part constrains intercalation of sandstone and shale, known as low resistivity low contrast zone (LRLC). The Talang Akar Formation from Air Batu and Sukomoro confers an excellent probability to observe and define LRLC zones over systematic approaches. This paper will provide an analogue of the LRLC reservoir zone by analyzing the relation between facies distribution and reservoir properties, including detailed shale structure. Facies distribution was obtained from the outcrop stratigraphic profile. The reservoir properties are identified by the Thomas Stieber plot and the petrographic section. Seven facies of Talang Akar Formation had been identified, which are: 1) planar cross-bedded sandstone (PCBS), 2) trough cross-bedded sandstone (TCBSS), 3) laminated sandstone (LSS), 4) heterolytic sandstone (HSS), 5) clay-rich sandstone (CSS), 6) mudstone (MS), 7) scour conglomeratic sandstone (SCSS). There are several types of shale distribution: structural shale, dispersed shale, and laminar shale. The laminar and dispersed shale consists of most of the reservoir and fills the pore. The clay structure deduces the disparity in the facies-porosity correlation. The finding of this study revealed that the LRLC zones are caused by lamination structures, thin intercalation layers, heterolytic and clay minerals.

scholarly journals Use of pedological maps in the identification of sensitivity of soils to acidic deposition: application to Brazilian soils

2004 ◽  
Vol 76 (1) ◽  
pp. 139-145 ◽  
Author(s):  
Adolpho J. Melfi ◽  
Celia R. Montes ◽  
Adilson Carvalho ◽  
Maria Cristina Forti
Keyword(s):  
Spatial Distribution ◽  
Clay Minerals ◽  
Acidic Deposition ◽  
Clay Fraction ◽  
Terrestrial Ecosystem ◽  
Environmental Studies ◽  
Saline Soils ◽  
Variable Amount ◽  
Brazilian Soils ◽  
Soil Distribution

The pedogeochemical maps present the spatial distribution of soils according to crystalochemical parameters (clay fraction) and physic-chemical aspects of the sorting complex (CEC and BS). These maps are adequate tool for environmental studies and particularly, for the analysis of the terrestrial ecosystem sensibility to acidic deposition. The pedogeochemical maps of the Brazilian soils, elaborated using FAO SoilWorld Map, allowed establishing the soil distribution according to 5 classes of vulnerability to acidic deposition, as defined by Stockholm Environmental Institute (SEI). From these maps, it is observed that about 50% of the Brazilian soils are high vulnerable to acidic deposition and can be included within the most sensitive class. This group is formed by well-developed and mature soils, constituted by clay minerals of kaolinite type associated with variable amount of gibbsite. About 8% of the soils can be considered as the least sensitive class. They correspond to Topomorphic Vertisols (Vertissolo, Embrapa 1999), Planosols (Planossolo, Embrapa 1999) and saline soils. Finally, the remaining soils represent the balanced media that dominate the northeastern semiarid zones and the south and northeastern subtropical zones.

An Early Tertiary Outcrop in North-Central Baffin Island, Northwest Territories, Canada: Environment and Significance

1972 ◽  
Vol 9 (3) ◽  
pp. 233-238 ◽  
Author(s):  
J. T. Andrews ◽  
J. D. Ives ◽  
G. K. Guennel ◽  
J. L. Wray
Keyword(s):  
Laminated Sediments ◽  
Coarse Grained ◽  
Baffin Island ◽  
Vertical Movements ◽  
North Central ◽  
Baffin Bay ◽  
Ice Cap ◽  
Early Tertiary ◽  
Warm Temperate

A thin, impure limestone was found in situ on Precambrian bedrock at latitude 70°36.6′ N and longitude 75°20′ W some 26 km northwest of the Barnes Ice Cap. The unit consists of undulating laminations composed of alternating fine- and coarse-grained sediment, which are interpreted as a series of algal mats or algal-laminated sediments. An analysis of enclosed palynomorphs indicates the presence of Ulmus, Taxodiutm, Liriodendron, Carpinus, and Engelhardtia plus other genera. On the basis of the microflora a Paleogene age is assigned to the unit. The climate at that time was warm-temperate and the environment suggested is a freshwater marsh or swamp. The outcrop is restricted to a single hill summit and its location suggests considerable Neogene geomorphological activity, primarily river-cutting associated with vertical movements along the western margin of the Davis Strait/Baffin Bay Tift.

Clay-Nanoarchitectures as Photocatalysts by In Situ Assembly of ZnO Nanoparticles and Clay Minerals

2018 ◽  
Vol 18 (1) ◽  
pp. 223-233 ◽  
Author(s):  
M Akkari ◽  
P Aranda ◽  
A. Ben Haj Amara ◽  
E Ruiz-Hitzky
Keyword(s):  
Clay Minerals ◽  
Zno Nanoparticles
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