The Upper Carboniferous (Westphalian A) Kozlu Formation consisting chiefly of sandstone, thick coal layers, shale, and conglomerate levels crops out in the Zonguldak-Amasra Basin, NW Anatolia. The Kozlu Formation contains a total of 20 mineable coal layers with the thickness varying from 0.5 to 6 m. The lower level of formation is represented by lacustrine deposits, whereas the upper part is made up of thick flood plain sediments and meandering river deposits bearing laterally continuous coal levels. In this study, coal samples taken from coal layers within the Kozlu Formation at the Kozlu Underground Coal Mining site were evaluated using the data obtained from pyrolysis/total organic matter (TOC), gas chromatography, and gas chromatography–mass spectrometry. The average total organic matter (TOC) value of Kozlu coals is 40.28%. The coals are characterized by relatively high hydrogen index (HI) value (average 262 mg HC/gTOC) and very low oxygen index value (2 mg CO2/gTOC). Pyrolysis data indicate that coals contain dominantly type II and less amount of type III kerogen, and T max values range from 454 to 468 °C. In gas chromatographs, the recorded distribution consists predominantly of low-carbon-numbered n-alkanes and subordinately of high-carbon-numbered n-alkanes and the terrigenous/aquatic ratio value is very low (0.05–0.09). Pristane abundance is greater than that of phytane, and Pr/Ph ratios are in the range of 1.11–1.60. The sterane abundances in the Kozlu coals are in the following order: C29 > C28 > C27. Coals have high C19 and C20 tricyclic terpane concentrations and high (C19 + C20)/C30 ratio, high C30* (diahopane) and C29Ts concentrations, and high C30*/C29Ts ratio and low C31R/C30 and C29/C30 hopane ratios. The dibenzothiophene-to-phenanthrene ratio of Kozlu coals is found to be very low (0.04–0.14). Based on the pyrolysis and biomarker data, the Kozlu coals are interpreted as being deposited in a suboxic–oxic continental environment in which there is effective input of clay and dominantly terrestrial (with significant lipid-rich components) and bacterial organic matter. High T max values, CPI values close to 1, low moretane/hopane (0.23–0.12), equilibrated 22S/(22S + 22R) homopane (for C32), 20S/(20S + 20R) C29 sterane (0.52–0.54) and TA­(I)/TA­(I + II) steroid ratios, high ββ/(ββ + αα) sterane (0.51–0.55), C30*/C29Ts, C30*/(C30* + C30H), MPI-3­(α/β) (1.24–1.41), and MDR and MA­(I)/MA­(I + II) steroid are indicative of mature–late mature organic matter. R o values between 0.9 and 1.25% determined from T max (454–468 °C) values indicate “high-volatile bituminous B–medium-volatile bituminous” rank for Kozlu coals. Kozlu coals having HI values (up to 331 mg HC/gTOC) extremely higher than those of classical coals indicates that these coals have significant oil and gas generation potential, and high S 1 (average 6.04 mg HC/g rock) and S 2 (110.08 mg HC/g rock) values imply that they generate notably high amount of liquid hydrocarbons and still have generation potential.

No abstract

No abstract

Major-element and trace-element content of oil shales in northwest Anatolia and their enrichment with respect to average shale have been investigated as well as the relationship between the total organic carbon (TOC) and different elements and the correlation between the different fields. The trace-element contents of the oil shales are generally similar, although the concentrations of some elements, such as As, B, Ba, Cr, Hg, Mo, Ni, and V, show a few differences. The contents of Ag, Au, B, Ba, Hg, Pb, Sb, Sn, Th, V, and Zn in the oil shales are lower than those of average shale. Only the Re concentration in all of the fields studied is greater than that in average shale. On the basis of the low-enrichment factors (<1) calculated for the trace elements, depletion of As, B, Ba, Cr, Hg, Ni, Pb, Sb, Sn, and Th in the Bahçecik field, Hg and Sn in the Gölpazarı field, and Sb in the Himmetoğlu field has been detected with respect to the average shale. Re shows the largest trace-element enrichment in all of the fields. In comparison to other elements, As, Mo, Ni, Se, Sr, U, Co, and Cr have higher enrichment values. The largest element enrichments have been generally observed in the Beypazarı and Seyitömer fields, whereas the lowest enrichments are typical of the Bahçecik field. Regarding the correlations between the elements and TOC, positive correlations with TOC at a significance level of p ≤ 0.05 or p ≤ 0.01 have been obtained as follows: Se in five fields, Cd in four fields, U in three fields, Th, Mo, Cu, Co, S, and Re in two fields, and Sb, P, Ca, K, Hg, Fe, and Zn in one of the fields. On the basis of the results from cluster analysis Se, U, and Mo in four fields, Th and Re in three fields, P and Ba in two fields, and Cd, K, V, Sr, Ca, Mn, Mg, B, and Ti in one of the fields comprise a group with TOC.

No abstract