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It is essential to identify marbles' petrographic and geochemical characteristics to determine the palaeo-environmental settings where their carbonate protoliths formed. The petrogenesis of massive Gimo marbles in the Gole area, Kurdistan Region of northeast Iraq, was investigated in this study through a combination of field mapping, petrographic, and geochemical techniques. Petrographic examination of these marbles reveals that mineral compositions are similar in all samples, with both homeoblastic and mosaic textures occurring, in addition to opaque grains that provide evidence of mineralization. Geochemical analyses show that the average calcium carbonate content of the marble is 94.96%; hence, the marble is lithologically characterized as a pure calcite marble. In most samples, the silica content was below 2 wt.%, with high values related to quartz veinlets. A range of geochemical indices and Post-Archean Australian Shale (PAAS–normalized rare earth element (REE) patterns) suggest that the limestone protolith was deposited in a shallow, near-shore marine environment on a continental margin, with very low input of detrital material. The negative Ce anomalies indicate that the protoliths of the Gimo marbles were carbonate rocks of a sedimentary origin.

The Middle to Late Eocene Mangahewa Formation in the Taranaki Basin has been evaluated for its petroleum system (source potential and reservoir qualities). The Mangahewa Formation is generally interpreted as an alternating marginal to shallow marine environment, with lithologies consisting of sandstone, siltstone, mudstone and bitumonius coal. The pyrolysis results show very good source rock generative potential with total organic carbon content of 0.8-90.02 wt. % and hydrogen index values in the range of 54- 491 mg HC/g TOC, with a predominance of oil- and/or gas-prone, mixed Type II-III kerogen. Organic petrographical data reveal that the humic nature of coals being rich in perhydrous vitrinite whereas shales are rich in alginite and bituminite desplaying frequent of migrabitumens. Biomarker analysis suggests predominantly terrigenous origin, whereas pyrolysis Tmax data (414–447°C) and other maturity indicators such as biomarkers and vitrinite reflectance indicates immature and mature samples. Petrographic analyses show that the occurrence of compaction and cementation is succeeded by leaching of feldspars and dissolution of calcite cement. The reservoir samples exhibit largely good reservoir quality with porosity being the dominant feature. The average porosity value is 15.7%, with 21.4% average water saturation. The source and reservoir units are part of a complete petroleum system of the Mangahewa Formation, with the overlying Turi Formation seal rock. The petroleum processes of maturation, generation, and migration which started since Lower Miocene (18.8 Ma) have been recorded in many stratigraphic traps within the Mangahewa Formation or other faulted structural traps due to migration. The generation process is expected to continue to the present day as the source continues to attain maturity while it does not yet reach the peak generation.

The karst bauxites of the Parnassos-Ghiona Unit (Greece) are hosted within Upper Jurassic to Late Cretaceous carbonate rocks. Three bauxite horizons are intercalated within shallow water limestones. They are named B1, B2 and B3 from bottom to top. In this study we present the characteristics of the B3 horizon (Cenomanian-Turonian) sampled in Agia Anna, Variani and Shila 1 underground mines. The bauxite ore has a prevailing oolitic texture. Diaspore, boehmite, hematite and goethite are the major mineral components of the analyzed samples. Kaolinite, rutile and anatase are common minor phases. Pyrite occurs in a small number of samples. Ilmenite, rutile, chromite, zircon, baddeleyite and serpentine are common detrital minerals. Authigenic minor minerals are mostly represented by REE-phosphates, barite, and gypsum. The presence of pyrite and diaspore suggests that after a first stage of additional in situ weathering and bauxitization, the deposits were affected by early diagenetic reducing conditions (allowing the formation of pyrite) and significant diagenesis, resulting in diaspore formation. This three-stages genesis is reflected in complex correlations between major, minor and trace elements. The occurrence of detrital chromite and serpentine in the bauxite reflects mafic parental rocks. The mafic component likely originated from the ophiolite suites exposed in the vicinity of the Parnassos-Ghiona bauxites.

Fifteen samples of the Lower Cretaceous Balambo Formation from three sections in the Zagros Fold-Thrust Belt, Kurdistan Region of northern Iraq have been studied by means of organic petrography, in order to assess the type and the thermal maturity of the contained organic matter. The microscopic study revealed that most of the samples are poor in primary macerals but do contain frequent solid hydrocarbons. In terms of macerals, only bituminite-like particles, vitrinite, both indigenous and reworked, and fusinite are observed; additionally, three types of solid hydrocarbons occur, these of microgranular and homogenous migrabitumen, as well as pyrobitumen. The equivalent vitrinite reflectance (Eq.VR. %) of solid microgranular migrabitumen of the Baraw section ranges between 0.55 and 0.68%, of the Bn-1 section between 0.58 and 0.73%, and for the Sazan section, the Eq.VR. % value is 0.58%. The Eq.VR. % for solid homogenous migrabitumen was calculated for the Baraw and Sazan sections samples, ranging from 0.68 to 0.72% and from 0.65 to 0.67%, respectively, whereas the Eq.VR. % for the pyrobitumens of Baranan-1.G1 ranges from 0.87 to 0.96%. These values indicate that the organic matter of the Balambo Formation in the studied sections reached early mature to mature stage, and possibly, liquid hydrocarbons were generated.

Summary A new potential source rock formation was discovered in Ionian Zone, Epirus region, western Greece and its organic petrographic and organic geochemical characteristics were investigated. The formation lies between the overlying lower Liassic “Pantokrator Limestones” and the underlying Rhaetian “Pantokrator Dolomites”. It consists of alternating organic-rich black shale and less organic-rich gray dolomite/dolomitic sandstone beds. The organic geochemical results suggest high amounts (up to 35,56 wt.% TOC) of Type I and II/IIS organic matter, with a Hydrogen Index up to 790 mg HC/g rock and a high remaining generation potential (S2) of 237,4 mg HC/g rock. Based on the mean Tmax of 422⁰C and on %VRo-eq from solid bitumens, formation hasn’t entered the oil window in this part of the basin. Nevertheless, presence of Type IIS kerogen in some samples, indicate that certain intervals of the formation may already have entered oil window and produced liquid hydrocarbons. Relatively high clastic input may be indicative of a climatic shift towards seasonably controlled wetter conditions, as it is inferred from adjacent areas. This study suggests that the stratigraphic position and the geochemical characteristics are comparable to intervals in Albania and Italy, possibly indicating a source rock interval with regional significance.

Upper Jurassic Naokelekan Formation, being part of the intercepted strata of the well-known Miran oilfield in Kurdistan region of Northern Iraq, has been previously extensively evaluated as a potential/effective source rock, mainly by means of organic geochemistry. In the present study, a total of 60 samples were collected from four Naokelekan Fm. outcrops, those of Banik, Galy-Derash, Barsarin and Dwawa, in order to conduct organic petrographical study and organic geochemical assessment, including both biomarker and Rock-Eval analyses. The average recorded TOC content for Banik, Galy-Derash, Barsarin and Dwawa section is considerable to very high, corresponding to values of 27.5, 9.0, 3.5 and 5.2 wt%, respectively, with the highest values representing the notably organic-rich bottom part of the Formation, known as “coal layer”. According to the petrographical analysis, solid migrabitumens comprise the predominant component for all the analysed samples, whereas the maceral groups of vitrinite, liptinite and/or inertinite showcase a minor to trace occurrence. In terms of organic geochemistry, each of the four sections of interest shows a different biomarker profile. Nevertheless, a number of calculated parameters related to kerogen type and depositional conditions, including the isoprenoids/n-alkanes ratios, suggest a mixed terrestrial-marine organic matter. Furthermore, as indicated by the Ro (%) measurements along with Rock-Eval parameters and the vitrinite reflectance equivalent based on aromatic compounds, the maturity level is marginally mature in the cases of Banik and Galy-Derash, whereas in the cases of Dwawa and Barsarin sections it is mature to post-mature. A synthesis of the organic petrography and geochemical appraisal applied in the present study, suggests that the reported solid hydrocarbons in Naokelekan Fm., particularly at its basal layers are non-indigenous/migrated and the precursor organic matter was deposited in a marine environment, under oscillating conditions ranging from euxinic to well‑oxygenated. Accordingly, the organic features of the notably bitumen-rich “coal-bed” fit the profile of a reservoir and/or migration path., This research was supported by the University of Patras, Greece, the University of Soran, KRG-Iraq, INCAR, Spain, as well as from EU Erasmus + Programme.

A recent field study in Northeastern Iraqi Kurdistan revealed the extensive occurrence of fuchsite mineral in listvenite bodies within the Zagros Ophiolites. Mineralogical and geochemical analytical techniques were applied to describe the features of the fuchsite-rich phases in relation to the various listvenite lithotypes. Fuchsite occurs in two main types: (i) as pale green flaky form infilling intensively fractured zones (type I), and (ii) as pale to intense green primary mineral crystals within the listvenite (type II). The main paragenesis associated with fuchsite includes quartz and clinochlore with variable Cr content, calcite and/or dolomite, and spinel. The results of this study suggest that fuchsite and the associated Cr-rich clinochlore have been formed as a result of metasomatic reactions of Si- and K-rich fluids with Cr-rich serpentine and Cr-spinel due to hydrothermal alteration of serpentinized peridotite within the Zagros Ophiolites.

Self-heating of coal waste is a major problem in the leading coal-producing and consuming countries, independent of the recent or past coal exploitation history. The phenomenon of self-heating is dependent on many factors such as the properties of organic matter (maceral composition and rank), moisture and pyrite content, climate effects, and storage conditions (shape of the dump or compaction of the coal waste). Once deposited, coal waste undergoes oxidation, which can lead to self-heating with the overall temperatures exceeding 1000 °C. During these self-heating processes, both organic and mineral matter undergo oxidative and thermal alterations, being influenced, among others, by the rate of heating as well as by the access of air and moisture. The morphological features of organic matter in coal waste at microscopic scale reflect the thermal conditions within the waste dump. Since 2008, several exercises designed to establish a petrographic classification system of oxidatively- and thermally-altered morphological forms of organic particles present in self-heated coal waste dumps have been carried out within the Self-heating of Coal and Coal Waste Working Group (Self-Heating WG), in Commission III of the International Committee for Coal and Organic Petrology (ICCP). Based on the degree of oxidative and thermal alteration, all assessed organic particles were divided into unaltered particles (huminite, vitrinite, liptinite, and inertinite macerals), altered particles, and newly formed particles (pyrolytic carbon, bitumen, chars, graphite, and coke). Altered particles were further divided according to their optical properties (porous, massive; isotropic, anisotropic). For altered particles the following specific features were distinguished: fractures, fissures, cracks; brighter rims; darker rims; plasticised edges; bands; devolatilisation pores; paler in colour particles. The final petrographic classification of oxidatively- and thermally-altered morphological forms of organic particles in coal waste dumps was established as a result of the successively performed Round Robin Exercises 2008–2017. The selected criteria and categories proved the high performance of the analysts characterised by a minor bias. The proposed petrographic classification system based on petrographic methods represents a useful way to characterize the undesirable phenomena occurring in coal waste dumps. Microscopic analyses and application of the petrographic classification system for organic particles affected by self-heating in coal waste offers the identification, documentation and monitoring of coal waste oxidation, self-ignition and combustion processes. It also enables a selection and application of appropriate measures to delay or even prevent undesired environmental impacts. The established classification system may assist in the air quality monitoring and assessment of burning waste dump sites and, thus, provide a relevant support in the environmental management of the disposal sites related to coal mining. The classification system can provide an important instrument for environmental protection agencies to increase the effectiveness of measures applied in fire hazard combating. The proposed classification of oxidatively- and thermally-altered morphological forms of organic particles in coal waste dumps can be applied on self-heating coal waste or mining dumps research, being a useful tool for coal waste managements performed by environmental agencies responsible for the landfill managements and monitoring of waste dumps., The samples used for preparation of the Round Robin Exercises within the Self-heating Working Group of the ICCP were obtained within the framework of the grants 2011/03/B/ST10/06331 and N307 016 32/0493 acquired by Magdalena Misz-Kennan from the National Center of Science, Poland. The research work conducted by Jolanta Kus within the Self-heating Working Group of the ICCP was supported and is published with the permission of the Federal Institute for Geosciences and Natural Resources, Hannover, Germany.

The characteristics of the source rocks in the early to late Miocene Belait Formation of Brunei Darussalam have been evaluated through the application of Rock-Eval and biomarker analyses, as well as by organic petrographical examination. Analyses have been performed on coal, coaly shale/carbonaceous claystones and shale samples from the Formation, retrieved from outcrops across the Brunei-Muara district, and covering a wide lateral extension of the Formation. The geochemical results indicate that the coal and some carbonaceous samples (with TOC from 14.1% to 67.7%) from the Belait Formation have “good to excellent” generating potential, quantity and quality, due to their high S2 and TOC values, which are consistent with the intermediate hydrogen index (HI) values ranging from 144 to 258 mg HC/g TOC. Organic material of “fair to good” quantity, quality and hydrocarbon generating potential is recorded for the coaly shale samples in the Belait Formation. Non-coal samples generally have the lowest potential as source rocks, due to their low TOC, HI and S2 values. Within the Formation, the coal layers together with a number of coaly shale and shale layers contain type III (gas prone) and type II-III (mixed oil and gas) kerogens. This is proven by the dominance of huminite, often of fluorescent varieties, which is confirmed though maceral analysis, as well as a trend of n-alkanes skewed towards heavier compounds. Evidence of the possible generation of liquid hydrocarbon is offered by the fact that liptinite is the second most abundant maceral group in most of the samples, as well as by the perhydrous nature of part of the huminite. Furthermore, kerogen type IV (dry gas) has been identified in a majority of the coaly shale samples. Facies analysis of the Belait Formation through the use of maceral indices and biomarkers data indicates that the coals were deposited in a mangrove setting in a lower delta plain, where mainly herbaceous and arboreal plants were growing. The depositional conditions were predominantly oxic, with a possible marine influence, and hence brackish conditions. All samples are found to be thermally immature to early mature, with Tmax values ranging from 356 °C to 441 °C, huminite reflectance values of up to 0.46% and high carbon preference index (CPI) values.

In this article, we report the discovery of a gossanite-type hematite and magnetite ore associated with sulfide mineralization in the Rayat area of NE Iraq. Detailed petrographic, mineralogical, and geochemical data define the features of the gossanite and the associated sulfide-rich rocks, providing an assessment of the mineralization and its relation to hydrothermal, microbial and alteration processes. The identified gossanite-like rocks are interpreted as part of a specific submarine gossan formed on the sulfide-rich serpentinite. In the uppermost part of the studied sequence, jasperite lithofacies occur, within which millimeter-thick layered iron oxide-silica alternations are also visible and comparable to the banded iron formation (BIF). Below the jasperite, an oxidized mineralized zone (OMZ) developed, representing gossanite that is exceptionally rich in iron oxides (up to 70%), chlorite, and quartz with some minor spinel content. The lowermost part of the studied sequence is the sulfide-rich reduced mineralized zone (RMZ) composed of silica, pyrite, chalcopyrite, pentlandite, Ni-chlorite, and siderite. The transition zone (TZ), approximately 1 m thick, between the OMZ and RMZ, contains chlorite, Fe-oxides, quartz, and partially altered sulfide minerals. The potential economic significance of the ore body in addition to Fe is the silver-nickel (Ag-Ni) and cobalt (Co) mineralization, with an average Ag concentration of 5.09 wt% per sulfide grain, which occurs as an exsolution phase within the sulfidic-cherts lithofacies. The Ni concentration ranged from 363 to 4,000 mg/kg, while that of Co ranged from 90 to 441 mg/kg, depending on the lithofacies. A thin lensoid coaly bed associated with the ore body, attributable to the Ophiolitic Melange, provides some initial clues for the epigenetic thermotectonic evolution of the studied strata. The overall data suggest that the Rayat gossanite, jasperite, and the underlying sulfide-rich zone were formed near the seafloor through a combination of initial hydrothermal alteration of serpentinites, which provided the sulfides, accompanied by the sedimentary deposition of Fe-Si-exhalatives along with the olistostromatic brecciated facies in the upper section, and the subsequent seafloor oxidation/weathering effects along microbial iron uptake. The discovery of gossanite and sulfides in the Rayat area, along with the already known chromitite deposits in the contiguous areas, highlights NE Iraq as a potential mineral-rich domain.

In the present study the palaeoenvironmental setting of the coastal mire/swamp zone called ‘Keri Lake’, on Zakynthos Island, west Greece is presented. The mire/swamp area is famous for the asphalt-pitch seepages named as ‘Herodotus-springs’. In order to interpret the Holocene evolution of the area, samples from four 7 m long vibracores were analyzed for their total organic carbon, total nitrogen and sulfur contents, as well as for their micro- and macro-fauna. The chronological framework of this study was based on three 14C ages, while the age depth model and the sedimentation rate were estimated applying OxCal software. The age depth model indicates that the cores cover the period from the middle Holocene to present, with a mean sedimentation rate of 1 mm/yr. Before 4000 BP large part of the area inundated by the sea while after 4000 yrs BP the ecosystem changed to a high marsh and gradually to a fen environment, where peat accumulated under telmatic to limnotelmatic conditions. The trends and the ratios of the geochemical markers TOC, TN and TS clearly reflect the palaeoenvironmental change from terrestrial to fen depositional environments. The results show that during the middle Holocene the Herodotus Lake was influenced by sudden sea water inundation events, possibly as a result of high waves or storm events, while since the late Holocene the setting is that of a brackish coastal fen, where peat accumulates, under the significant inflow of fresh water that originates from the karstic systems of the catchment area.

This paper investigates an alternative use of sterile aggregate materials which may arise from various construction applications in conjunction with other low-cost mineral raw materials to remediate the acid mine drainage phenomenon. This study is based on the combination of unprocessed mineral raw materials, as well as on the basic concept of the cyclic economy where the conversion of a waste into a raw material for another application can be achieved. In this study, in order to examine the remediation, in lab scale, of the drainage waste water of Agios Philippos mine, an experimental electrically continuous flow-driven forced device was constructed, enriching the research gap relative to this type of remediation approach. Through this experimental device, the use of certain mixes of mineral raw materials (serpentinite, andesite, magnesite, peat, and biochar) was studied. Our results focus on the impact of the studied mineral raw materials and especially on their synergy on the water purification potential under continuous water flow operation. Using the new 7-day experimental electrically continuous flow-driven forced device with certain mixes of mineral raw materials, the increase of pH values from 3.00 to 6.82 was achieved. Moreover, with use of the experimental device, the removal of toxic load was achieved, and more specifically the concentration of Fe was decreased from 6149 to 1300 ppb, Cu from 8847 to 35 ppb, and Zn from 285,458 to 50,000 ppb.

This paper investigates an alternative use of sterile aggregate materials which may arise from various construction applications in conjunction with other low-cost mineral raw materials to remediate the acid mine drainage phenomenon. This study is based on the combination of unprocessed mineral raw materials as well as on the basic concept of the cyclic economy where the conversion of a waste into a raw material for another application can be achieved. In this way, the value of mineral raw materials can be prolonged for as long as possible, waste generation and exploitation of natural resources are minimized and resources are kept as far as possible within the existing economy. In this study, an electrically continuous flow driven forced device proposed and demonstrated for the remediation of waste water in lab-scale by using certain mixes of mineral raw materials (serpentinite, andesite, magnesite, peat and biochar). Our results focus on the impact of the studied mineral raw materials and especially on their synergy on the water purification potential under continuous water flow operation. Using the proposed 7-day experimental electrically continuous flow driven forced device with the certain mixes of mineral raw materials, the increase of pH values from 3.00 to 6.82 as well as significant removal of Fe, Cu and Zn was achieved.

Upper Jurassic Naokelekan organic-rich strata are ubiquitous across the Kurdistan Region of Iraq. Laterally, continuous layers, of substantial thickness, outcrop in the highly folded and imbricated zones and in subsurface sections in the Low Folded Zone. In this study, 15 samples from 5 outcrops, viz., Barzinja, Sargelu, Barsarin, Karak, and Bnavya, were examined, which represent the entire lithological alternations of limestones and shales encountered in the Whole Naokelekan Formation. This study assesses the type, the thermal maturity and the petroleum generation potential of the organic matter contained in the upper Jurassic Naokelekan formation throughout the area. The qualitative petrographical evaluation of the studied samples revealed that the main organic constituents are solid hydrocarbons, in the form of microgranular migrabitumens, with minor amounts of pyrobitumens. Equivalent vitrinite reflectance estimations (0.59–1.12% Ro) indicate that the upper Jurassic sequence in the western part of the area is at a mature stage, while the same sequence in the eastern part is at late mature stage.

An interlaboratory study (ILS) was conducted to test reproducibility of vitrinite and solid bitumen reflectance measurements in six mudrock samples from United States unconventional source-rock reservoir petroleum systems. Samples selected from the Marcellus, Haynesville, Eagle Ford, Barnett, Bakken and Woodford are representative of resource plays currently under exploitation in North America. All samples are from marine depositional environments, are thermally mature (T >445 °C) and have moderate to high organic matter content (2.9–11.6 wt% TOC). Their organic matter is dominated by solid bitumen, which contains intraparticle nano-porosity. Visual evaluation of organic nano-porosity (pore sizes < 100 nm) via SEM suggests that intraparticle organic nano-pores are most abundant in dry gas maturity samples and less abundant at lower wet gas/condensate and peak oil maturities. Samples were distributed to ILS participants in forty laboratories in the Americas, Europe, Africa and Australia; thirty-seven independent sets of results were received. Mean vitrinite reflectance (VR) values from all ILS participants range from 0.90 to 1.83% whereas mean solid bitumen reflectance (BR) values range from 0.85 to 2.04% (no outlying values excluded), confirming the thermally mature nature of all six samples. Using multiple statistical approaches to eliminate outlying values, we evaluated reproducibility limit R, the maximum difference between valid mean reflectance results obtained on the same sample by different operators in different laboratories using different instruments. Removal of outlying values where the individual signed multiple of standard deviation was >1.0 produced lowest R values, generally ≤0.5% (absolute reflectance), similar to a prior ILS for similar samples. Other traditional approaches to outlier removal (outside mean ± 1.5*interquartile range and outside F10 to F90 percentile range) also produced similar R values. Standard deviation values < 0.15*(VR or BR) reduce R and should be a requirement of dispersed organic matter reflectance analysis. After outlier removal, R values were 0.1%–0.2% for peak oil thermal maturity, about 0.3% for wet gas/condensate maturity and 0.4%–0.5% for dry gas maturity. That is, these R values represent the uncertainty (in absolute reflectance) that users of vitrinite and solid bitumen reflectance data should assign to any one individual reported mean reflectance value from a similar thermal maturity mudrock sample. R values of this magnitude indicate a need for further standardization of reflectance measurement of dispersed organic matter. Furthermore, these R values quantify realistic interlaboratory measurement dispersion for a difficult but critically important analytical technique necessary for thermal maturity determination in the source-rock reservoirs of unconventional petroleum systems., This research was funded by the USGS Energy Resources Program.

This paper investigates the interrelationships between the engineering properties of igneous aggregate rocks from Greece with the aid of the R-mode factor analysis. The collected samples represent mafic and ultramafic rocks from the ophiolite complexes of Gerania, Guevgueli, Veria-Naousa, and Edessa as well as intermediate-acidic rocks from the surrounding areas of the complexes. Factor analysis verifies the important interdependences among the engineering parameters like physical, mechanical, geometrical, and physicochemical properties by giving statistical significance. Variations of the petrographic characteristics of the investigated rocks influence their engineering properties as well as the interdependence among them. Factor 1, which is the most representative one (~36% of the total variance), shows interdependences between certain physical, mechanical, physicochemical properties such as total porosity (nt) with moisture content (w), nt with the Los Abrasion value (LA), and the uniaxial compressive strength (UCS) with point load index Is(50). Additionally, the second factor (~27% of the total data variability) correlates physical properties such as w, nt, physicochemical properties such as the methylene blue test (MBF), mechanical properties such as UCS, Is(50), and loss on ignition (LOI), which highlights the effect of mineralogy on these properties. Lastly, Factor 3 (~14% of the total data variability) expresses the interdependence of the flakiness index (IF), which is an elongation index (IE) relative to their alteration (LOI).

In this study, the features of fly ashes originating from industrial-scale high volatile bituminous coal combustion and co-combustion of coal with 10% admixture of alternative fuel SRF (solid recovered fuel) are presented, with emphasis on the organic petrographical characteristics. The organic petrographical and mineralogical data are co-evaluated with geochemical data, with the aim to provide a full classification of the studied fly ashes, as well as base information toward any potential application of this waste material, according to the recycling economy principles. By applying organic petrographical methods, the assignment of the carbon-rich residuals to the respective feed fuel, either coal or SRF, can be achieved. The obtained quantitative evaluation provides useful information regarding the combustion conditions in the stoker boiler. The analyzed fly ashes contain significant C-residuals, mostly in the form of fused, dense, and anisotropic particles, while the enrichment in sooty particles is caused due to the addition of SRF fuel. In conjunction with the moderate-low content of potential hazardous elements, the features of the contained C-residual phases suggest that these fly ashes could possibly be the subject of further studies for their applicability as soil improvements.

The aim of this study is to assess the type, thermal maturity and the petroleum generation potential of the Upper Jurassic Naokelekan Formation, occurring across the Kurdistan Region of Iraq, by applying organic petrographical methods and Rock-Eval analysis. The Rock-Eval data would indicate the presence of kerogen types III, IV and II as the main constituents. However, the qualitative petrographical evaluation revealed that the main organic constituents are solid hydrocarbons, in the form of microgranular migrabitumens, with minor amounts of pyrobitumens. These secondary particles have affected the results of the Rock-Eval analysis and would have led to misinterpretation of organic matter typification based on pyrolysis results only. The combined results of petrography and pyrolysis indicate an active petroleum system within the Upper Jurassic sequence, where hydrocarbons are generated and reservoired within suitable lithologies.

Coal layers up to 1 m thick, exposed mainly on river banks in the vicinity of Agbor, Okhuokhuo and Ubiaja, Southern Nigeria, were examined by means of organic petrology, mineralogy and geochemistry, in order to gain coal quality data and understand the palaeoenvironmental conditions during peat accumulation in the broad area of the Ogwashi-Asaba Formation. The obtained results show that coal is of low-rank C; it overlies mainly claystone derived from flooding of branches of the palaeo-Niger River. The precursor peat was accumulating in mires under mesotrophic to ombrotrophic, anoxic conditions. The peat-forming vegetation represented mainly herbaceous plants with minor tree contribution. Though the number of studied samples is low, the distribution of the lignite layers extends further towards N.NW of the known lignite-bearing area. Taking into consideration the low ash yields of some samples, there are encouraging indications for notable lignite deposits of high quality. The mineralogical composition and the activity concentrations of 238U, 226Ra, 232Th and 40K exclude any severe environmental effect from coal exploitation. Due to all these promising evidences, a detailed exploration in these and between these outcrops is recommended in order to estimate the lignite potential hosted in this area.

A recent geological field work in the Northeastern part of Iraqi Kurdistan and subsequent analytical studies showed that the previously reported metamorphosed limestone outcrops around Rayat area represent actually listvenite bodies. Field mapping and remote sensing applications were used to understand the spatial distribution of the listvenite; additionally petrographical, mineralogical and geochemical studies were applied in order to define the features of the listvenite and to provide an initial genetic model, as well as to assess potential mineralizations related to the listvenitization. Listvenitization occurred as a product of hydrothermal alteration of the Cr-rich serpentinised peridotite that extensively occurs in the area, and resulted in the formation of silica and carbonate listvenites, as well as transitional phases, with fuchsite mineralization being predominant along the sheared zones. The results of this study upgrade the broad area of Rayat as potential hydrothermal ore-forming system and provide a basis for future detail prospecting of the area.

Maceral analyses along with proximate and elemental analyses were undertaken in order to determine the features of the Amynteo coal deposit and its depositional environment. The Amynteo coal has an eu-ulminite B reflectance of Rr = 0.21%, and in terms of lithotype belongs to matrix lignite. Huminite is the most abundant maceral group, consisting mostly of detrohuminite. Inertinite has relatively low percentages whereas liptinite concentrations are rather high. A ternary plot was applied as an indication of the depositional paleoenvironment. The results from the majority of the samples indicate origin in a topogenous setting. The peat accumulation was governed by a high groundwater level (wet telmatic to limno-telmatic facies). The depositional environment can be characterized as a reed-marsh environment, with occasional establishment of forest swamps.

The low-grade base metal sulphide Cu–Zn–Pb and Fe mineralization of Qandil Series develop in shear zones that occur in formations of the north-western part of the Zagros Orogen. This sulphide mineralization occurs either as quartz vein type or disseminated type associated with metamorphic rocks (marbles and phyllites). This study aims to characterize these sulphide-rich ores by means of their mineralogical and geochemical features, including also the features of the corresponded host formations and those of marbles (calcitic and dolomitic) and phyllites. Petrographical data indicate the presence of Cu, Zn, Pb and Fe sulphides in hydrothermal quartz (±calcite) veins of different generations. Geochemical data of surface samples indicate enrichment of Cu and Fe in shear zones with low concentrations in Zn and Pb. The REE data indicate that the genesis of these sulphide ores took place in a hydrothermal system and was generally attributed to high temperature (> 250 °C).The mineralization seems to be fault-controlled, which is favoured by the significant tectonic deformation of the area.

A new system for the microscopic classification of fly-ash components has been developed by the Fly-Ash Working Group, Commission III of the ICCP and is presented herein. The studied fly-ashes were obtained from the combustion of single coals of varied rank, coal blends, and coals blended with other fuels (biomass, petroleum coke), in different operating conditions and by means of different technologies. Microscopic images of the fly-ash samples were used to test the optical criteria proposed for classifying the fly-ash components. The classification system developed is based on a small number of microscopic criteria, subdivided into six independent levels or categories, three of which are directed at whole particle identification on the basis of nature, origin and type of fly-ash particle, while the other three levels are directed at the smaller section identification on the basis of character, structure and optical texture of unburned carbons. To classify the inorganic components of the fly-ash, the criterion proposed is composition in terms of metallic/non-metallic character. To establish the classification criteria the petrographers involved in the work performed three successive round robins. Evaluation of the results by using firstly descriptive statistics and then the criteria and parameters employed by the ICCP in their accreditation programs indicated that the classification of the fly-ash components was accurate and that there was only a minor bias. The main conclusion of this study was that the proposed criteria are valuable for identifying, and classifying fly-ash components and for describing the optical properties of fly-ash particles.

Thermal maturity and palaeodepositional environment of the Taratu Formation has been studied by evaluating its geochemical properties and organic petrographical features. Geochemical properties of the Cretaceous-Palaeocene Taratu source rock that are identified through pyrolysis indicate that this formation has excellent organic matter quality, quantity and hydrocarbon generation potential. Only the Cretaceous-aged sequence from this formation is thermally mature, with Tmax values ranging from 429 °C to 459 °C, while Palaeocene samples are found to be thermally immature. Organic matter of the Taratu Formation comprises primarily of oil and gas prone kerogen type II-III and gas prone kerogen type III, which is reflected by high HI (165.0–327.5 mg HC/g TOC) and low OI (5.00–25.7 mg CO2/g TOC) values. Tissue Preservation Index (TPI) and Gelification Index (GI) indicates that the Taratu Formation was previously deposited in a limnic environment. Further assessment of the source rock's palaeodepositional environment through correlating cross-plots of various biomarker data and evaluation of organic petrography suggests that the formation was subjected to brackish water influx.

A new high-resolution Last Interglacial pollen record from the Tenaghi Philippon peatland, northeast Greece, documents variability in forest composition and cover, which we attribute to changes in temperature and moisture availability. The declining stage of the interglacial was marked by a stepwise decrease in temperate tree populations and culminated in the complete collapse of forest at the onset of the ensuing stadial. The coincidence of the onset of the stepwise declining trend with the increased prominence of North Atlantic ice-rafting events suggests that ecological thresholds in southern Europe were only crossed once ice rafting events intensified, and implies that changes in North Atlantic ocean circulation were an important contributing factor to the declining temperate forest cover in southern Europe. Our results provide evidence for intra-interglacial variability in the low mid latitudes and suggest a coupling between the high northern latitudes and the northeast Mediterranean during this interval. Copyright # 2013 John Wiley & Sons, Ltd.

The deposition of sapropels in the eastern Mediterranean Sea is thought to occur during intervals of intensified African monsoon and increased precipitation in the Mediterranean borderlands. Speleothem and pollen records, however, reveal conflicting evidence for a Mediterranean-wide precipitation increase, suggesting that seasonal changes in the hydrological regime may be important. Using a multiproxy record, we present the first independent evidence for seasonality of precipitation during the early Last Interglacial (ca. 130–119 ka) from the Tenaghi Philippon peatland in northeast Greece. During the early part of the interglacial, mineralogical, macrofossil, and pollen records from the same core show a shift from mire to lacustrine conditions simultaneous with an expansion of sclerophyllous vegetation and the presence of acicular aragonite, indicating the onset of highly evaporative summer conditions. This indicates enhanced seasonality of precipitation and reconciles the apparent incongruity between Mediterranean pollen and speleothem records. It also provides evidence for significantly increased winter precipitation coeval with the deposition of sapropel S5, one of the most prominent sapropels of the Pleistocene. We suggest that in addition to the summer African monsoon component, increased winter precipitation from the northern Mediterranean borderlands may have contributed to maintaining reduced surface-water salinities in the Mediterranean Sea over the entire year.

The Achlada and Mavropigi lignite deposits in northern Greece provide the main coal source for the next generation of Greek power plants. A comparative characterization of these two lignite deposits is presented, covering the coal rank and the features of the maceral components, based on detailed coal petrography, and the mineralogical and geochemical features of the coals and their ashes, based on XRF and XRD analyses. The data are used to interpret the palaeoenvironments of the lignite beds, as well as factors that may affect their burnout behavior. Both deposits have a lignite C rank. The Mavropigi lignite is mainly a matrix lignite lithotype, whereas the Achlada deposit consists both of matrix and xylite-rich lithotypes. The Achlada lignite was formed in a fluviatile environment, mainly in the abandoned channels of a meandering river system during flooding periods; hence it is enriched in inorganic matter, with ash values > 30 wt.%. The Mavropigi lignite formed in a reed-marsh environment under limno-telmatic conditions, and displays ash values The inorganic matter of the two deposits is different in composition due to the contrasting environments, and these differences should be taken into account in optimizing their utilization for power production. A preliminary assessment indicates that the Achlada lignite may have more favorable slagging and fouling properties than the Mavropigi lignite, although experimental studies are required for more solid conclusions to be reached.

Ο τυρφώνας της Αγουλινίτσας σχηματίστηκε στη δυτική ακτή της ομώνυμης λίμνης, η οποία αποξηράνθηκε το 1969, εξαιτίας της αυξανόμενης ζήτησης για καλλιεργήσιμες εκτάσεις. Η παρούσα μελέτη αποτελεί μια πρώτη προσπάθεια για τη διερεύνηση των συνθηκών που επικρατούσαν κατά την τυρφογένεση. Για τις ανάγκες της μελέτης πραγματοποιήθηκαν διατρήματα μικρού βάθους, καθώς και προσδιορισμοί των φυσικών, χημικών ιδιοτήτων της τύρφης, και των ορυκτολογικών συστατικών της. Η υψηλή περιεκτικότητα σε τέφρα και οι υψηλές τιμές του pH υποδηλώνουν πως η τύρφη σχηματίστηκε κάτω από αλκαλικές συνθήκες, ενώ οι υψηλές τιμές της ηλεκτρικής αγωγιμότητας υποδηλώνουν έντονη τροφοδοσία με διαλυμένα στερεά. Στην τύρφη προσδιορίστηκαν αργιλικά ορυκτά, χαλαζίας, ασβεστίτης, αλίτης, συλβίτης και σιδηροπυρίτης. Η κατανομή των παραπάνω ορυκτών με το βάθος υποδηλώνει την επικράτηση συνθηκών γλυκού νερού κατά το μεγαλύτερο διάστημα απόθεσης της τύρφης στο κεντρικό τμήμα της περιοχής, ενώ στο νότιο τμήμα η επίδραση της θάλασσας ήταν πιο έντονη και οι συνθήκες χαρακτηρίζονται ως ελαφρά υφάλμυρες. Συμπερασματικά ο τυρφώνας της Αγουλινίτσας μπορεί να χαρακτηριστεί ως ένας τυρφώνας που σχηματίστηκε πίσω από αμμώδεις φραγμούς. Παρόμοιες συνθήκες κυριαρχούσαν ήδη από το Νεογενές, στις δυτικές ακτές της Πελοποννήσου και ευνόησαν τη γένεση λιγνιτικών κοιτασμάτων στην ευρύτερη περιοχή, The Agoulinitsa peatland formed on the western shore of the homonymous lake, which was drained in 1969 because of the emerging demand for agricultural land. This study is a preliminary attempt to determine the conditions that prevailed during peat formation. Shallow cores were obtained from the peatland and initial physical, chemical and mineralogical analyses were carried out. High ash yield and pH values indicate that peat accumulated under alkaline conditions with periods of high clastic material influx, while high electric conductivity values indicate increased influx of dissolved solids into the mire. The mineral matter consists mainly of clay minerals, quartz, calcite, halite, sylvite and pyrite. The distribution of these minerals with depth indicates that fresh-water conditions prevailed for a long period during peat accumulation at the central part of the peatland, whereas the sea-water influence was more intense to the south establishing slightly brackish conditions. All data suggest that the Agoulinitsa peatland was developed as a back-barrier mire formed at the southwestern part of the Agoulinitsa Lake, and hence it can be considered as a modern analogue of the Neogene lignite deposits occurring along the west coast of Péloponnèse

The Pera-Lakkos coal located on top of bauxite deposits in the Ghiona mining district (Central Greece), is the only known Mesozoic (Late Cretaceous) coal in the country. It was derived from herbaceous plants and algae growing in mildly brackish mires that formed behind a barrier system during a regression of the sea, on a karstified limestone partly filled in with bauxitic detritus. Petrological, mineralogical and geochemical data point to the predominance of reducing conditions and intense organic matter degradation in the palaeomires. O/C vs. H/C and OI vs. HI plots, based on elemental analysis and Rock-Eval data, characterize kerogen types I/II. This reflects the relatively high liptinite content of the coal. Besides kerogen composition, O/C vs. H/C plot for the Pera-Lakkos coals is in accordance with a catagenesis stage of maturation in contrast with vitrinite reflectance and T max from Rock-Eval pyrolysis, which indicate the onset of oil window maturation stage. Suppression of vitrinite reflectance should be considered and the high liptinite content corroborates this hypothesis. Despite some favourable aspects for petroleum generation presented by the Pera-Lakkos coal, its maximum thickness (up to 50 cm) points to a restricted potential for petroleum generation. Coal oxidation took place either during the late stage of peat formation, due to wave action accompanying the subsequent marine transgression, or epigenetically after the emergence of the whole sequence due to percolation of drainage waters. Both options are also supported by the REE shale-normalized profiles, which demonstrate an upwards depletion in the coal layer. Oxidation also affected pyrite included in the coal; this led to the formation of acidic (sulfate-rich) solutions, which percolated downwards resulting in bleaching of the upper part of the underlying bauxite.

Oxidised lignite is a potential alternative source of N fertilizers. Ammonoxidation is the reaction of a given substrate with oxygen in aqueous ammonia. Lignite ammonoxidation is used for converting low-rank lignite into slowly nitrogen-releasing artificial humic matter. A lignite sample is compared before and after ammonoxidation in terms of geochemical and petrological properties, as well as the acid–base and physical hydrophobic sorptive behavior. The most obvious change caused by ammonoxidation is the decrease of attrinite, texto-ulminite and textinite in favor mainly of densinite and gelohuminite. In general, the ammonoxidative reactions promote the destruction of the structured humic macerals (texto-ulminite, textinite), and the formation of gels, which resulted in the cementation of the freely fine humic particles (attrinite). The pzc values are 3.4 and 4.3 for oxidised and non-oxidised lignite, respectively. After ammonoxidation the contents of carboxylic and free phenolic groups are found to be lower. The oxidised lignite shows a statistically lower sorptive capacity and affinity than the original sample due to a possible decrease in the hydrophobicity of the lignite.

The present study aims to elucidate the depositional environment of Seam I in the Megalopolis Basin, Southern Greece, using existing geological data supported by maceral and mineralogical analyses, as well as by natural radioactivity determinations. Very high pyrite and uranium contents and a very low tissue preservation index usually suggest a marine influence during deposition. In Seam I, however, these features are most probably the result of a karstic aquifer supplying the palaeomire with sulphate-rich, neutral to weakly alkaline water. The pyrite formation and the U precipitation are attributed to the anaerobic conditions, which prevailed during peat accumulation. The petrographic, mineralogical and geochemical data of the studied profile point to several changes in the surface runoff and the supply of clastic material during deposition.

Summarization: Twenty-eight samples of peat, peaty lignites and lignites (of both matrix and xylite-rich lithotypes) and subbituminous coals have been physically activated by pyrolysis. The results show that the surface area of the activated coal samples increases substantially and the higher the carbon content of the samples the higher the surface area. The adsorption capacity of the activated coals for NO, SO2, C3H6 and a mixture of light hydrocarbons (CH4, C2H6, C3H8 and C4H10) at various temperatures was measured on selected samples. The result shows a positive correlation between the surface area and the gas adsorption. In contrast, the gas adsorption is inversely correlated with the temperature. The maximum recorded adsorption values are: NO = 8.22 × 10− 5 mol/g at 35 °C; SO2 = 38.65 × 10− 5 mol/g at 60 °C; C3H6 = 38.9 × 10− 5 mol/g at 35 °C; and light hydrocarbons = 19.24 × 10− 5 mol/g at 35 °C. Adsorption of C3H6 cannot be correlated with either NO or SO2. However, there is a significant positive correlation between NO and SO2 adsorptions. The long chain hydrocarbons are preferentially adsorbed on activated lignites as compared to the short chain hydrocarbons. The results also suggest a positive correlation between surface area and the content of telohuminite maceral sub-group above the level of 45%. Presented on: International Journal of Coal Geology