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Wyszukujesz frazę "Deposits" wg kryterium: Temat


Tytuł:
Unusual development of sandur sedimentary succession, an example from the Pleistocene of S Poland
Autorzy:
Salamon, Tomasz
Zieliński, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/94593.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
outwash deposits
sedimentology
Pleistocene
Polska
osady sandrowe
sedymentologia
plejstocen
Polska
Opis:
An atypical lithological development of outwash deposits in the Carpathians Foreland (S Poland) shows lower and middle parts of the sedimentary succession that are characterized by sinuous palaeochannels. This channel facies consists of laterally accreted sands derived from side bars. The sedimentary environment was a proglacial system of anabranching channels, presumably of anastomosed type. The outwash channel pattern was most probably controlled by the raising base level of the fluvial system. Both proglacial and extraglacial waters were dammed by a sandur within a small upland valley. Aggradation and progradation of the glaciofluvial deposits resulted in progressive rising of the dammed lake level. The low hydraulic gradient of the outwash streams resulted in a sinuous planform as well as a lowenergy style of deposition. Afterwards, the rising lake water was drained off through a low watershed and the entire valley became filled with outwash sediments. The bedrock morphology thus became buried and a typical unconfined sandur with a braided channel network developed during the last phase of the glaciomarginal sedimentation (upper part of the sedimentary succession under study).
Źródło:
Geologos; 2010, 16, 2; 83-99
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quaternary deposits and weathered bedrock material as a source of dangerous radon emissions in Estonia
Autorzy:
Petersell, V.
Jüriado, K.
Raukas, A.
Shtokalenko, M.
Täht-Kok, K.
Powiązania:
https://bibliotekanauki.pl/articles/94608.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
radon
uranium
klint
graptolite argillite
Quaternary deposits
till
uran
argilit
osady czwartorzędowe
Opis:
The risk of dangerous radon emissions in Estonia is high, being among the highest in Europe. In almost 33 per cent of Estonian land area, the content of radon in soil-contained air exceeds the safe limit for unrestricted construction (50 kBq/m3). In such high radon-risk areas the concentration of radon in soil-contained air ranges from 50 to 400 kBq/m3, in a few cases reaching up to 2,100 kBq/m3 exceeding the permitted level for residential areas. The situation is particularly serious in the northernmost part of the country, where uranium-rich graptolite argillite (Dictyonema shale) and the Obolus phosphorite are close to ground surface and their particles are constituent parts of Quaternary deposits. Radon emissions from bedrock have been investigated in detail, but to date Quaternary strata as a source of radon emissions are poorly studied. According to our measurements the highest concentrations of radon are related to tills containing clasts and fines of graptolite argillite and phosphorite. Glacial deposits include also granitoidal material, containing U, Th and K, which have been transported by glaciers from the outcrop areas of crystalline basement rocks in Finland and the Gulf of Finland. Due to weathering, outwash and repeated redeposition other genetic types are poorer in radioactive elements and they are weaker sources of radon.
Źródło:
Geologos; 2015, 21, 2; 139-147
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geneza skałek wierzchowinowych Płaskowyżu Ojcowskiego na podstawie badań osadów stokowych
Origin of hilltop monadnocks on the Ojców Plateau as reconstructed from slope deposits
Autorzy:
Pawelec, Halina
Powiązania:
https://bibliotekanauki.pl/articles/94432.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
skałki
osady stokowe
plejstocen
Płaskowyż Ojcowski
monadnocks
slope deposits
Pleistocene
Ojców Plateau
Polska
Opis:
Artykuł podejmuje dyskusję dotyczącą genezy skałek wierzchowinowych na Płaskowyżu Ojcowskim. W odróżnieniu od najczęściej obecnie stosowanej w badaniach skałek metody, opartej wyłącznie na analizie geomorfologicznej, podstawą badań jest szczegółowa analiza osadów stokowych - powstałych równocześnie z niszczeniem skałek. Badania przeprowadzono w rejonie Jerzmanowic, pomiędzy górnymi odcinkami dolin Będkowskiej i Szklarki, na obszarze falistej wierzchowiny ze skałkami. Opracowano szczegółowe profile litologiczne osadów stokowych. Wykonano badania uziarnienia oraz zawartości CaC03, Fe203 i Corg. Dla frakcji iłowej wykonano analizy mineralogiczne. Badania wykazały, że występujące na stokach obszaru osady powstały w środowisku peryglacjalnym, w rezultacie wietrzenia mrozowego, sedymentacji lessu oraz redepozycji materiału gruzowego i lessowego przez procesy stokowe. Analiza sukcesji tych osadów oraz analiza procesów glebowych wskazują, że są to osady górnovistuliańskie. Na podstawie analizy rozmieszczenia poszczególnych typów osadów wnioskowano o zależnościach pomiędzy procesami peryglacjalnymi a rzeźbą stoków. Głównym kierunkiem przeobrażania ścian skałek było boczne cofanie w rezultacie wietrzenia mrozowego i odpadania wapieni. W obrębie falistej wierzchowiny, wypukły profil górnych części stoków jest rezultatem współdziałania wietrzenia mrozowego i soliflukcji. Dolne, wklęsłe części stoków zostały uformowane w wyniku depozycji osadów soliflukcyjnych i deluwialnych oraz okresowej redepozycji tych osadów, głównie przez spłukiwanie. Podczas plejstocenu obszar Płaskowyżu Ojcowskiego ulegał intensywnej denudacji, uwarunkowanej cyklicznymi zmianami klimatu. W środowisku peryglacjalnym działało głównie wietrzenie mrozowe i procesy stokowe. Podczas interglacjałów oraz interstadiałów działały procesy wietrzenia krasowego. Rezultatem plejstoceńskich procesów denudacyjnych, które rozwijały się na podłożu przeobrażonym przez kras, są współczesne formy skałek oraz rzeźba falistej wierzchowiny. Wyniki badań wskazują, że dotychczasowe teorie, dotyczące wieku i genezy skałek, nie doceniały znaczenia plejstoceńskiej morfogenezy dla rozwoju rzeźby Płaskowyżu Ojcowskiego.
The origin of the monadnocks on the Ojców Plateau has been analysed not only on the basis of morphology but also by sedimentological analysis of the slope deposits that cover the slopes around the monadnocks. The investigations were carried out in the area of Jerzmanowice, between the upper courses of the Będkowska and Szklarka valleys within the undulated plateau where the monadnocks form the highest parts. Detailed lithological profiles were prepared, the granulometry was determined, and the CaC03, Fe203 and Corg content was estimated. Within the Clay fraction, mineralogical analyses were carried out. It is shown that the deposits covering the slopes developed in a periglacial environment as a result of frost weathering, loess sedimentation and reworking of scree and loess by slope processes. Both lithology of these deposits and the traces that soil processes left indicate an upper Vistulian age. The distribution of the individual lithofacies points to a distinct influence of periglacial processes on the slope relief. The main process was lateral retreat of rock walls as a result of frost weathering and rock fall. A convex profile of the upper parts of the slopes resulted due to the joint action of frost weathering and solifluction. The lower parts of the slopes, in contrast, developed a concave surface as a result of solifluction and surface wash, i.e. periodical redeposition of sediments. During the Pleistocene, the area of the Ojców Plateau underwent intensive denudation conditioned by cyclic climate changes. Frost weathering and slope processes were the most important under periglacial conditions. During interstadials, chemical weathering occurred in the active layer of the permafrost. Outcropping Jurassic limestones and the slope cover underwent karst processes. It is concluded that the present-day relief of the undulating plateau with monadnocks in the Cracow Upland results from the Pleistocene denudation processes. Surface degradation was stimulated during the Pleistocene by differential resistance of the rock units transformed by subsurface karst. Earlier studies concerning the age and origin of the monadnocks in this region underestimated the Pleistocene denudation.
Źródło:
Geologos; 2008, 14, 2; 163-176
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sedimentary record of a Pleistocene ice-sheet interlobate zone (NE Poland)
Autorzy:
Gruszka, Beata
Morawski, Wojciech
Zieliński, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/94281.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
interlobate sedimentation
outwash deposits
esker
Weichselian
NE Poland
sedymentacja
osady sandrowe
oz
Polska Północna
Opis:
Well developed NE-SW trending corridors of outwash in NE Poland are associated with a series of lakes with a similar direction of elongation. The glaciofluvial corridor under study consists of parallel ridges with associated channels and kames. The deposits are flanked by till and hummocky terrain. The gravel ridges are composed of sand and gravel deposits that are cross-stratified, massive or graded, and that contain cut-and-fill structures and large intra-clasts of sand and gravel. Locally the deposits show normal faults. The succession of one of the ridges is interpreted to reflect the infilling of a braided channel in a crevasse. Sedimentation took place in some phases when the ice-sheet regime changed from active to stagnant. Sandy-gravel ridges occur within this complex perpendicular to the Weichselian icesheet margin. The corridor is interpreted as an interlobate area in the zone between the Warmia and Mazury ice lobes. The braided-channel deposits are not comparable to typical Polish sandurs. The lithofacies characteristics show higher energy conditions, and the channels are deeper than those typical of Pleistocene lowland sandurs. The sand and gravel ridges are interpreted as interlobate eskers.
Źródło:
Geologos; 2012, 18, 2; 65-81
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The assemblages of transparent heavy minerals in Quaternary sediments of the Kielce-Łagów Valley (Holy Cross Mountains, Poland)
Autorzy:
Ludwikowska-Kędzia, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/94365.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
heavy mineral analysis
Quaternary deposits
Holy Cross Mountains
analiza ciężkich minerałów
złoża czwartorzędowe
Góry Świętokrzyskie
Opis:
The composition of the transparent heavy-mineral assemblages (0.25-0.1 mm) in Quaternary slope, karst, glacial, fluvioglacial and fluvial deposits with different parent material was investigated in the Kielce-Łagów Valley (the central part of the Palaeozoic core of the Holy Cross Mountains). For the purpose, 93 samples of mostly sandy sediments were examined. Some marker and some supporting minerals can be distinguished. Slope and karst deposits are dominated by the abrasion-resistant minerals zircon, tourmaline, staurolite and rutile. This assemblage points at a source consisting of strongly weathered pre-Quaternary bedrock. Glacial and fluvioglacial deposits are dominated by medium-resistant and non-resistant minerals (garnet, amphibole, pyroxene and biotite). The two types of parent material of the heavy minerals are typical of the Quaternary deposits in the Polish uplands. The two sources are most clear in the younger (Vistulian and Holocene), mostly fluvial sediments. The results of the analysis imply that the impact of Pleistocene glaciers on the central part of the Holy Cross Mountains was neither large enough to hide the local mineralogical background, nor sufficient to dominate over the main processes transforming the mineral composition under the variable climatic conditions of the Quaternary, including aeolian processes and chemical weathering.
Źródło:
Geologos; 2013, 19, No. 1-2; 95-129
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Predictive diagenetic clay-mineral distribution in siliciclastic rocks as a tool for identifying sequence boundaries in non-marine successions: the Coalspur Formation, west-central Alberta
Autorzy:
Khidir, Ahmed
Catuneanu, Ovtavian
Powiązania:
https://bibliotekanauki.pl/articles/94436.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
sequence stratigraphy
non-marine deposits
siliciclastics
diagenesis
clay minerals
stratygrafia sekwencji
krzemionki
diageneza
minerały ilaste
Opis:
The study of upper Cretaceous - lower Tertiary fluvial deposits of the Coalspur Formation in the Foothills region of west-central Alberta reveals that the distribution of early authigenic kaolinite has a well-defined relation to the sequence stratigraphic framework. In this context, it has been observed that the kaolin mineral content increases in sandstones lying below subaerial unconformities, which mark the most significant stratigraphic hiatuses and hence the sequence boundaries in fully fluvial successions. The increased abundance of authigenic kaolinite immediately below sequence boundaries may have been caused by the infiltration of meteoric water during times of subaerial erosion, resulting in the dissolution of unstable minerals (e.g., micas and feldspar) and the formation of kaolinite and secondary porosity. It is therefore suggested that the change in clay mineral assemblages in the stratigraphic section depends in part on the position of the analyzed sandstone samples relative to the sequence boundaries. In a larger context, the method of using authigenic clays to delineate depositional sequences in non-marine successions needs to be evaluated on a case-by-case basis, as the diagnostic early diagenetic minerals underlying the sequence boundary may change as a function of palaeoclimate and also as a function of late diagenetic processes.
Źródło:
Geologos; 2009, 15, No. 3-4; 169-180
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The evolution of a Weichselian proglacial lake in NW Poland as revealed by static penetration tests
Autorzy:
Wierzbicki, Jędrzej
Paluszkiewicz, Renata
Paluszkiewicz, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/94539.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
glaciolacustrine deposits
varves
overconsolidation
CPTU method
Pomeranian Lakeland
Polska
osad glacjalny
prekonsolidacja
Pojezierze Pomorskie
Polska
Opis:
The lithology, structure and geophysical characteristics of the glaciolacustrine clays deposited in the Wierzchowo proglacial lake were determined using static penetration tests (CPTU) in combination with standard lithological measurements. The deposits are divided into four lithological units (R1 to R4) on the basis of overconsolidation. Units R3 and R4 are separated by mass-flow deposits. The depositional conditions history of the lake result represent four phases: (1) an initial (low-energy) phase with the deposition of the rhythmically laminated sediments of units R1 and R2, which are divided by an erosional interval; (2) a phase of non-deposition with some desiccation structures and extended consolidation of sediments; (3) the main phase characterised by deposition of the rhythmically laminated sediments of unit R3; and finally, (4) the youngest phase, which represents alternations of deposition and erosion. The results show that sedimentation in the Wierzchowo proglacial lake was less continuous, and that the depositional processes were more complex than in the neighboring Złocieniec glacial lake.
Źródło:
Geologos; 2011, 17, 2; 111-119
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prospects and limitations of heavy mineral analyses to discriminate preglacial/glacial transitions in Pleistocene sedimentary successions
Autorzy:
Zieliński, T.
Powiązania:
https://bibliotekanauki.pl/articles/94637.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
river network
fluvial deposits
stratigraphy
Early Pleistocene
Polska
sieć rzeczna
osady fluwialne
stratygrafia
plejstocen
Polska
Opis:
The present study revolves around the identification of the stratigraphical boundary between Pleistocene formations that formed prior to the first advance of the Scandinavian ice sheet (Early Pleistocene, i.e., the so-called preglacial) and the overlying, glacially derived deposits (Middle Pleistocene). In particular, it focuses on variation in heavy mineral assemblages, which are an important tool for stratigraphers. The Neogene basement, described here, was most often the source of material that was redeposited by Early Pleistocene rivers. The geological structure and Early Pleistocene palaeogeographical scenarios for various Polish regions are discussed. Moreover, comparisons with other European preglacial formations are carried out. The mineral spectrum of Lower Pleistocene deposits is largely dependent of rocks of the Neogene and Mesozoic basement. If the incision of ancient catchments was into terrigenous rocks, the stratigraphical boundary between preglacial and glacial formations is easily determined with the help of a heavy mineral analysis. As a rule, this coincides with a noticeable change from resistant to non-resistant mineral associations. Such cases are noted for successions in central Poland and eastern England. On the other hand, outcrops of igneous or metamorphic rocks exist within preglacial river catchments in most parts of Europe. They were the local sources of non-resistant heavy minerals long before their glacial supply from the Baltic Shield. In these cases, mineralogical analysis fails in the search for the Early/Middle Pleistocene transition.
Źródło:
Geologos; 2018, 24, 2; 151-162
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Alternative interpretations of grain-size data from Quaternary deposits
Autorzy:
Mycielska-Dowgiałło, Elżbieta
Ludwikowska-Kędzia, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/94466.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
Quaternary deposits
grain-size distribution
cumulative curve
frequency curves
textural parameters
osady czwartorzędowe
skład granulometryczny
parametry teksturale
Opis:
Several possibilities to present and to interpret the results of granulometric analyses of Quaternary fluvial, aeolian, glacial and wash-out slope deposits were investigated. Attention is paid particularly to the cumulative curves at a probability scale and the frequency curves, and it is shown how these curves can help to determine the sedimentary environment. The inclination of the cumulative curves in the part of the maximum proportion of a particular grain size appears significant. It appears possible to obtain information on the density and dynamics of the transporting medium from the course of the cumulative curves (inclination and spread of grain size). The examination of textural parameters allows to draw regression lines characteristic of both deposits from various sedimentary environments and deposits from one single environment but with different histories as to their transport dynamics.
Źródło:
Geologos; 2011, 17, 4; 189-203
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Petrographical analysis of Warthian fluvioglacial gravels as a tool to trace the source area – a case study from central Poland
Autorzy:
Górska-Zabielska, M.
Wachecka-Kotkowska, L.
Powiązania:
https://bibliotekanauki.pl/articles/94704.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
gravel petrography
indicator erratics
fluvioglacial deposits
Warthian stadial
central Poland
żwirowa petrografia
eratyki przewodnie
osady fluwioglacjalne
centralna Polska
Opis:
The petrographical features of the medium- and coarse-grained gravels (4-10 mm and 20-60 mm, respectively) of weathered and fresh (unweathered) deposits indicate, in combination with so-called indicator and statistical erratics, that two glacial lobes joined in the borderland of the Polish Lowlands and Uplands. Lower Palaeozoic limestones become less frequent in the finer gravel fraction, whereas crystalline rocks and flints become more frequent. The petrographical analysis of the coarser gravel fraction indicates that the ice sheet advanced from the NE to NNW (the Widawka lobe) and from the NE to ENE (the Rawka, Pilica and Luciąża lobes). The source areas of the gravel deposited by the Warthian ice sheet were magmatic and sedimentary areas of both the Baltic and the SE Sweden basins.
Źródło:
Geologos; 2014, 20, 3; 183-199
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Depositional environment of the Bagh-e-Vang Formation – the only occurrence of upper Lower Permian in Iran
Autorzy:
Yegane, Bizhan Yousefi
Van Loon, A.J. (Tom)
Fard, Sakine Arefi
Farahpour, Mohammad Mehdi
Sharahi, Safoora Yasbolaghi
Powiązania:
https://bibliotekanauki.pl/articles/1841615.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
limestones
microfacies analysis
transgression conglomerate
barrier deposits
lagoonal environment
Tabas Block
wapienie
analiza mikrofacjalna
konglomerat
transgresja
osady
laguna
Opis:
A transgression of the Tethys Ocean occurred in east central Iran, like in other areas of the Tethys Ocean, around the Yakhtashian/Bolorian (regional chronostratigraphical units corresponding with the Artinskian/Kungurian of the Early Permian) transition. This led to the development of a carbonate platform that is represented in the Shirgesht area on the northern part of the Tabas Block by the Bagh-e-Vang Formation, which constitutes the only known sedimentary unit from the late Early Permian in Iran. Field data and thin-section analysis indicate deposition on a carbonate ramp with barriers separating a lagoonal area with intertidal mud flats from the open-marine environment. The overall transgres-sive development is indicated by the presence of open-marine sediments on top of the barrier and lagoonal sediments.
Źródło:
Geologos; 2021, 27, 1; 1-14
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Younger Dryas Cladocera assemblages from two valley mires in central Poland and their potential significance for climate reconstructions
Autorzy:
Pawłowski, Dominik
Powiązania:
https://bibliotekanauki.pl/articles/94461.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
Younger Dryas
Cladocera
oxbow-lake deposits
valley mire
climate
local conditions
młodszy dryas
złoża
starorzecze
torfowisko
klimat
warunki lokalne
Opis:
Two sections of sediment from small oxbow-lake infillings located in different river valleys in central Poland were studied by cladoceran analysis in order to examine the response of aquatic ecosystems to the Younger Dryas. Lithological and geochemical records, as well as chydorid (Chydoridae) ephippia analysis were also used to reconstruct Younger Dryas climate trends. A high concentration of cladocerans, as well as the presence of Cladocera taxa preferring warmer water, was found. It is likely that local processes in the oxbow lakes were important, because the presence of warm-preferring taxa was also related to their habitats and their development. Yet local environmental forces, such as the influence of the rivers, habitat modification, macrophyte abundance, and eutrophication, were not only major factors to affect the Cladocera diversity in the Younger Dryas. The observation of changes in the composition and concentration of Cladocera in oxbow-lake infillings indicates that most of the changes occurred in response to climate changes.
Źródło:
Geologos; 2012, 18, 4; 237-249
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gemstones of eastern Kazakhstan
Autorzy:
Chlachula, Jiri
Powiązania:
https://bibliotekanauki.pl/articles/94440.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
Altai
non-metallic mineral deposits
gemstone
decorative stones
prehistory
field exploration
jewellery
Ałtaj
kamienie szlachetne
kamienie ozdobne
prehistoria
badania terenowe
biżuteria
Opis:
An overview is presented of gemstones from eastern Kazakhstan in terms of their geographical distribution, geological provenance and genesis, gemmological characteristics, historical use and current applications. Locally occurring precious, semi-precious and decorative stones were extracted and traded along the northern part of the Silk Road that traversed the area in earlier historical times. Currently, non-metallic minerals, which largely originate from mafic igneous and metamorphic bodies of the Altay and Kalba Mountains of Kazakhstan, still are insufficiently known and exploited industrially only marginally. For the present study, selected depositories of coloured stones at the Mineralogy Museum of the East Kazakhstan State Technical University were used, supplemented by the newly collected material during personal fieldwork in the southern Altay between 2005 and 2015. Standard documentation of the gemstones selected is provided, alongside with their known occurrence sites and an evaluation of the perspective gemstone-bearing deposits with respect to regional morphostructural bedrock characteristics. The most precious gemstones include topaz, corundum (sapphire and ruby), beryl (emerald and aquamarine), coloured tourmalines, agates as well as diamonds. Despite the great variety, the majority of these traditionally most valued stones are currently commercially not viable, unlike high-quality decorative stones.
Źródło:
Geologos; 2020, 26, 2; 139-162
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy-mineral assemblages from fluvial Pleniglacial deposits of the Piotrków Plateau and the Holy Cross Mountains - a comparative study
Autorzy:
Wachecka-Kotkowska, Lucyna
Ludwikowska-Kędzia, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/94384.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
heavy mineral analysis
fluvial deposits
Vistulian
Pleniglacial
central Poland
Holy Cross Mountains
Piotrków Plateau
analiza ciężkich minerałów
osady rzeczne
Wisła
środkowa Polska
Góry Świętokrzyskie
Opis:
The heavy-mineral assemblages of Pleniglacial fluvial sediments were analysed for two river valleys, viz. the Luciąża River (at Kłudzice Nowe) and the Belnianka River (at Słopiec). These sites, on the Piotrków Plateau and in the Holy Cross Mountains respectively, are located in different morphogenetic zones of Poland that were affected to different degrees by the Middle Polish ice sheets. The study was aimed at determining the kind of processes that modified the heavy-mineral assemblages in the two fluvial sediments, at reconstructing the conditions under which these processes took place, and in how far these processes caused changes in the assemblages. The heavy-mineral associations of the parent material was taken as a starting point; this parent material were the sediments left by the Odranian glaciation (Warta stadial = Late Saalian). It was found that heavy-mineral assemblages in the Luciąża valley deposits are varied, particularly if compared with other fluvioglacial Quaternary deposits from the Polish lowlands, with a dominance of garnet. In the fluvial deposits of the Belnianka valley, zircon, staurolite and tourmaline dominate, with minor amounts of amphibole, pyroxene, biotite and garnet. This suggests that the deposits were subject to intensive and/or persistent chemical weathering and underwent several sedimentation/erosion cycles under periglacial conditions. In both valleys chemical weathering and aeolian processes were the main factors that modified the assemblages of the transparent heavy minerals; these processes were largely controlled by the climatic changes during the Pleistocene.
Źródło:
Geologos; 2013, 19, No. 1-2; 131-146
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy and light minerals as a tool for reconstructing depositional environments: an example from the Jałówka site (northern Podlasie region, NE Poland)
Autorzy:
Woronko, Barbara
Rychel, Joanna
Karasiewicz, Mirosław T.
Ber, Andrzej
Krzywicki, Tomasz
Marks, Leszek
Pochocka-Szwarc, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/94625.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
heavy minerals
quartz grain
periglacial processes
source deposits
Vistulian glaciation
NE Poland
minerały ciężkie
ziarna kwarcu
procesy peryglacjalne
złoża źródłowe
zlodowacenie Wisły
Polska północna
Opis:
Part of northern Podlasie (NE Poland), shaped during the Wartanian stadial of the Odranian glaciation (Saalian), was situated in the periglacial zone during the Vistulian (Weichselian) glaciation. Both landforms and sediments were affected by the periglacial conditions. This is recorded at the Jałówka site, at the floor of a dry valley, where mineral deposits of 4.13 m thick, overlying organic deposits from the Eemian interglacial, were examined. These mineral deposits form four units, from bottom to top: a fluvial unit (I), a loess-like unit (II), a solifluction unit (III), and an aeolian unit with ice wedges (IV) on top of unit III. The heavy and light minerals were analysed, as well as the geochemistry, in order to find out about the parent material and to reconstruct the climatic conditions during deposition. The mineral analysis indicates that the Saalian till was predominantly derived from shallow-marine deposits; erosion accompanied by sorting of the heavy minerals took place on the basis of their mass and grain size. The original material of the till seems therefore to be sedimentary rocks from the eastern Central Baltic Basin. This material became strongly weathered under the periglacial conditions, resulting in the destruction of the quartz grains, as well as in leaching, leading to complete decalcification of the deposits. Aeolian activity resulted in infilling of ice wedges and the creation of thin layers. The intensity and the duration of these processes was limited, so that the effects of the aeolian abrasion are insignificant. Neither resulted the aeolian activity in significant reshaping of the landscape.
Źródło:
Geologos; 2013, 19, No. 1-2; 47-66
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł

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