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| Titel |
Organic Geochemistry of Oltu Gemstone Coal, Erzurum (NE Turkey) |
| VerfasserIn |
R. Kara-Gülbay, S. Korkmaz, G. Yaylalı-Abanuz |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250071456
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| Zusammenfassung |
| The Oltu Gemstone, also known as Black Amber, is a type of coal that has bright, completely
homogenous and black colored characteristics. The Oltu Gemstone occurrences are located
around the Dutlu Village in the northern Oltu (Erzurum, NE Turkey). The Oltu Gemstone
levels are located within the sequence composed of sandstone, marl, siltstone and
claystone alternation with lens-shaped (max. 0.50 m thickness and a few meters
length). Operation is being carried out in small underground mine by local private
company.
The TOC and HI values vary from 70.01 to 78.56 % wt. and 357 to 379 mg HC/gr
rock, respectively. The pyrolysis (Rock-Eval) data indicate that the Oltu Gemstone
samples consist of Type II kerogen. Tmax values are between 417 and 436oC. In
gas chromatograms of samples, less amount of n-alkanes and isoprenoids were
recorded.
Tricyclic terpanes contents of Oltu Gemstone samples are of lower than hopanes and C30
hopane is dominant compound in m-z 191 mass chromatogram. C31 homohopanes are
dominant over the others and homohopane distributions decrease towards the higher members
in the m-z 191 mass chromatograms of the Oltu Gemstone samples. Moratane/hopane,
Ts/(Ts+Tm) and C31 homohopane/C30 hopane ratios of samples are very low. In m/z 217
mass chromatograms, the pregnanes are recorded in high amount and diasterane
concentrations are lower than those of steranes. (20S+20R) and ββ/(ββ + αα) sterane ratios
are 0.35-0.24 and 0.24-0.16, respectively. 22S/(22S+22R) homohopane ratios are between
0.56 and 0.62, and these ratios indicate that homohopane isomerization reached
equilibrium.
C27 and C28 triaromatic (TA) steranes are dominant component, and C20 and C21 TA
steranes were recorded in lower/higher amount for different samples. In m-z 253 mass
chromatograms, C21 and C22 monoaromatic (MA) steranes are recorded in lower amount
than long-chain MA steranes, and C28 and C29 MA steranes are dominant compounds.
In m/z 178 and 192 mass chromatograms, phenanthrenes (P) are dominant over
alkylphenanthrenes (MP) and, 9MP and 1MP were recorded in higher amount than the
other MPs (MPI-1; MPI-2= 0.35-0.34; 0.41-0.42, respectively). In the m-z 184
and 198 mass chromatograms, dibenzothiophene (DBT) concentrations are higher
alkyldibenzothiophene (MDBT) and 2MDBT are dominant peak than the other MDBTs
(4MDBT> 1MDBT). The P contents are in higher amount than DBT contents and P/DBT
ratios of the Oltu Gemstone samples were estimated to be between 3.04 and 5.72. |
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