Geology topics

M. Mastalerz

Publications and source records attributed to M. Mastalerz.

4 recordsLinked to original sources

USGS2026

Multi-proxy thermal history of basin heating during Cordilleran orogenesis in the Magallanes-Austral retroarc foreland basin, Patagonian Andes

Resolving thermal histories in sedimentary basins is crucial for interpreting orogenic growth, basin burial, and tectonic processes during Cordilleran orogenesis. In the Magallanes–Austral Basin, Patagonian Andes, we integrate new (U-Th)/He thermochronology, vitrinite reflectance (%R o ), calcite-cement clumped isotope data and thermal history modelling to resolve the origin of the regionally extensive Paleogene unconformity (51°S–50°S). Thermal history modelling results require post-depositional heating of Palaeocene (Danian–Selandian) strata below the unconformity and suggest maximum burial temperatures of 87°C–101°C (55–52 Ma) and 89°C–92°C (18–16 Ma). For lower Eocene strata above the unconformity, Miocene burial temperatures (89°C–92°C) are consistent with calcite cement formation temperatures (~62°C–92°C) from carbonate clumped isotopes. Our results indicate that basin burial and heating between ca. 60 and 52 Ma were likely driven by shallowing of the subducting Farallon plate and enhanced plate coupling preceding arrival of the Farallon–Phoenix mid-ocean ridge. Subsequent basin inversion and cooling from ca. 52 to 44 Ma correspond with subduction of this mid-ocean ridge. Refined thermal models, constrained by expanded thermochronometric and organic maturation datasets, indicate that up to ~1.7–2.0 km of proximal foreland basin strata were removed during uplift and erosion across the Paleogene basin margin. A return to basin subsidence beginning ca. 44 Ma may reflect dynamic subsidence after passage of the mid-ocean ridge and renewed coupling between the fold-thrust belt and foreland basin system. Neogene thermal histories document continued subsidence, localized hot orogenic fluid flow along stratigraphic boundaries, followed by a final phase of basin inversion and cooling at ca. 18–16 Ma, which we attribute to regional uplift associated with Chile ridge subduction. Altogether, this study demonstrates that multiple thermal indices when analysed and modelled can provide clarity for tectonic and stratigraphic events that affect foreland basins.

Patagonian Andes↗

USGS2024

Structure and morphology of chars and activated carbons obtained from thermal treatment of coal and biomass origin materials, including their wastes: Results from the ICCP Microscopy of Carbon Materials Working Group

This paper describes the evaluation of petrographic textures in char and activated carbon derived from coal, coal by-products and biomass, formed during carbonization and activation processes. This work represents the results of interlaboratory exercises from 2016 to 2022 of the Microscopy of Carbon Materials Working Group in Commission III of the International Committee for Coal and Organic Petrology. The interlaboratory exercises were run on photomicrograph samples. For textural characterization of carbon materials, the existing American Society for Testing and Materials (ASTM) classification system for metallurgical coke was applied. Morphological differences were evaluated in 29 carbon material types, including 22 char samples, and 7 activated carbon (AC) samples obtained experimentally using conventional direct/indirect and microwave heating technologies. This approach gives an extended view on the identification of microporous carbons, and how a certain heat treatment develops a certain optical texture and structure in a raw material. The requested evaluation of carbon materials was related to their porosity, origin, extent, and characteristics, which are particular to each carbon material type. Because carbon matrices can form a wide range of optical textures during heat treatment it is important to demonstrate which carbon occurrences will have a crucial role in industrial applications dominated by adsorption phenomena. The interlaboratory exercises included 17 participants from 14 laboratories. Four sets of digital black and white and colour photomicrographs were distributed, which in total comprised 184 fields of different types of carbon material. The results were evaluated based on four levels: (i) optical texture (isotropic/anisotropic), (ii) optical type and size (punctiform, mosaic, fiber, ribbon, domain), iii) morphology (porous, non-porous/massive), and (iv) particle origin (precursor type). The statistical method applied to evaluate the results was based on “raw agreement indices”. Comparative analyses of the average values of the level of overall agreement showed homogeneity in the results, the mean value was 89%, with a minimum value of 87% and a maximum value of 91% for those who participated in at least three out of four exercises.

International Journal of Coal Geology↗

USGS2019

Hydrous heating experiments at 130°C yield insights into the occurrence of hydrogen sulfide and light alkanes in natural gas reservoirs

Improved understanding of the origin of produced volatiles from conventional reservoirs and unconventional source rocks is critical for petroleum exploration and production. A series of hydrous heating experiments using two immature Type II siliciclastic source rocks, Pennsylvanian Turner Mine shale (TMS) and Devonian New Albany Shale (NAS), at 130 °C over one to two years were conducted to assess gas generation at low temperature. Elemental sulfur (ES) was added to the NAS samples to evaluate the role of sulfur on thermochemical sulfate reduction (TSR). The produced volatile composition was investigated in situ using Raman spectroscopy at the end of the heating experiments. Results show that the two source rocks yield different types and concentrations of volatiles. Only CH 4 and CO 2 were detected following hydrous heating of the TMS source rock in contrast to CH 4 , C 2 H 6 , C 3 H 8 , and CO 2 which were observed in experiments using NAS. Variations in the produced volatiles are likely the result of compositional differences within the respective source rock organic matter. Experiments involving ES show strong H 2 S signals that are likely due to the formation of H 2 S from the reaction of ES with water at 130 °C. H 2 S signals correlate with a greater relative concentration of CH 4 and CO 2 compared to experiments where ES was not added, on a time-normalized basis. The correlation between the presence of H 2 S and an increase in CH 4 and CO 2 concentration could indicate the occurrence of TSR. Here we propose that H 2 S in siliciclastic shale can be generated in the presence of ES at low temperatures via both disproportionation of ES into H 2 S and SO 4 2– , and TSR. Our findings from this study provide experimental evidence that may aid efforts to interpret the origin of H 2 S in low-temperature sedimentary basins.

Pennsylvania↗

USGS2017

Identification of alginite and bituminite in rocks other than coal. 2006, 2009, and 2011 round robin exercises of the ICCP Identification of Dispersed Organic Matter Working Group

The paper presents results of round robin exercises on photomicrograph-based identification of dispersed organic matter in source rocks that represent a range of marine and lacustrine deposits from worldwide localities and cover a range of thermal maturities. The round robin exercises were conducted by the Identification of Dispersed Organic Matter Working Group (IDOM WG) of the International Committee for Coal and Organic Petrology (ICCP). The round robin exercises aimed to (1) assess the applicability of the established ICCP definitions of bituminite, (2) identify deficiencies and improve the existing nomenclatures, and (3) provide a basis for the revision of the bituminite and alginite definitions in the ICCP Handbook (Taylor et al., 1998). Three round robin exercises performed in 2006, 2009 and 2011 involved 18 participants from research laboratories at universities and within government and industry. Participants were asked to identify macerals on the basis of existing definitions in 129 photomicrographs taken in incident white light and fluorescent mode and also in fluorescence light mode at prolonged (15 min) blue light irradiation. The results indicate that the definition of telalginite permits its positive and satisfactory agreement among the participants. In contrast, the descriptive characteristics of lamalginite referring to film-like appearance (filamentous) and lack of inner or outer structure are insufficient and inadequate to enable an unequivocal discrimination between it and telalginite. Furthermore, based on the amorphous nature of bituminite and lack of adherence to its established description and character (Taylor et al., 1998), the highest discrepancies were observed in its identification. Differentiation of bituminite from a fluorescent groundmass and in some cases from lamalginite proved to be particularly challenging. The findings of these round robin exercises are useful for improving the identification of sedimentary organic matter in source rocks and may be an important foundation for the modification of the ICCP definitions of alginite and bituminite.

International Journal of Coal Geology↗