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Grigo, Domenico
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Grigo, Domenico
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- PublicationOpen AccessAssessment of thermal evolution of Paleozoic successions of the Holy Cross Mountains (Poland)(2017)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Poland is considered the most prospective country for shale gas production in Europe. Hydrocarbon generation/expulsion scenarios, drawn in the latest intensive exploration phases, tend to overestimate maturation levels when compared with brand new data acquired after recent drillings. We tested an integrated workflow to correlate published and original thermal maturity datasets for the Paleozoic to Jurassic successions cropping out in the Holy Cross Mountains. These successions, when preserved in subsurface, host the major source rocks in the area. The application of the workflow allowed us to highlight the burial and thermal evolutionary scenarios of the two tectono-stratigraphic blocks of the Holy Cross Mountains (Łysog ory and Kielce blocks) and to propose this approach as a tool for reducing levels of uncertainty in thermal maturity assessment of Paleozoic successions worldwide. In particular, published datasets including colour alteration indexes of Paleozoic microfossils (conodont, acritarchs) and vitrinite and graptolite reflectance data, show differences in levels of thermal maturity for the Łysog ory (mid mature to overmature) and Kielce (immature to late mature) blocks. Original data, derived from optical analysis, pyrolysis, and Raman spectroscopy on kerogen, and X-Ray diffraction on finegrained sediments, mostly confirm and integrate published data distribution. 1D thermal models, constrained by these data, show burial and exhumation events of different magnitude, during the Late Cretaceous, for the Łysog ory (maximum burial depths of 9 km) and Kielce (burial depths of 6 km) blocks that have been related to the Holy Cross Fault polyphase activity. In the end, Palynomorph Darkness Index and Raman spectroscopy on kerogen, for Llandoverian and Cambrian rocks, turned out to be promising tools for assessing thermal maturity of Paleozoic organic facies devoid of vitrinite macerals.342 73 - PublicationRestrictedThermal maturity of Silurian deposits in the Baltic Syneclise (on-shore Polish Baltic Basin): contribution to unconventional resources assessment(2015-05-21)
; ; ; ; ; ; ; ; ; Shale gas is envisaged to contribute in the next future to the European energy mix in the prospective of lowering CO2 emissions. Poland is by far one of the most perspective countries in Europe. In the “Golden Belt”, potential productive levels are Early Paleozoic in age and the reliable assessment of their thermal maturity is crucial for evaluating hydrocarbon generation/expulsion scenarios. When exploring Lower Paleozoic targets that are devoid of vitrinite macerals, uncertainties in thermal maturity evaluation can occur according to commonly adopted parameters (e.g., vitrinite reflectance). These uncertainties can negatively influence targets assessment. We adopted a multi-method approach to assess thermal maturity of the Silurian sections encountered in three wells deep between 2.9 and 3.3 km, recently drilled in the Polish Baltic Basin. The methodological strategy consists of: (i) measurement of organoclasts (mainly graptolites) reflectance; (ii) FT-IR spectroscopy on bulk dispersed organic matter; (iii) X-ray diffraction on <2 μm grain-size fraction of sedimentary core samples. Organoclasts reflectance is between 0.6 and 1.4% indicating a large range of thermal maturity spanning from early to late mature stages of hydrocarbon generation. Mixed layers illite-smectite and FT-IR indexes (e.g. CH2/CH3, A and C) allowed us to improve the definition of thermal maturity of Lower Paleozoic rocks (Roeq between 0.8 and 1.1%). This original dataset indicates lower levels of thermal maturity than those predicted in pre-existing thermal maturity maps, suggesting that the Silurian sections experienced thermal maturity conditions equivalent to the oil window more than the gas window.314 16 - PublicationRestrictedAn integrated platform for thermal maturity assessment of polyphase, long-lasting sedimentary basins, from classical to brand-new thermal parameters and models: An example from the on-shore Baltic Basin (Poland)(2020)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Paleo-thermometers in sedimentary basins often drive to misleading thermal modelling when applied alone or only on potentially productive Paleozoic source rocks. Different paleo-thermal and thermo-chronological data have been used as constraints to model the Silurian to Cenozoic succession of a recently drilled well in the onshore portion of the Baltic Basin, in northern Poland. This dataset provides an integrated platform for thermal maturity assessment contributing to the highly debated reconstruction of the thermal history of the Baltic Basin in the last decade. The well stratigraphy consists of a Lower Paleozoic marine clayey and arenaceous/calcareous succession, about 1000 m thick that is unconformably overlain by a 2000 m thick Permian to Cenozoic sequence, developed in a continental to shallow marine environment. Optical microscopy, FT-IR and Raman spectroscopy analysis of organic matter have been coupled with (U–Th)/He data to produce a robust vitrinite reflectance profile and constrain the 1D thermal modelling of the well. In addition, such a thermal maturity profile was validated by an independent thermal modelling calibrated by the smectite illitization kinetics. Both models identify high heat flow conditions (up to 1.7 HFU) at the end of Mesozoic. The Lower Paleozoic succession entered the late oil window of HC generation during this last heating event.244 3 - PublicationRestrictedExhumation patterns along shallow low-angle normal faults: an example from the Altotiberina active fault system (Northern Apennines, Italy)A multi-method approach (palaeothermal and thermochronological analyses; thermal modelling) is applied to reconstruct the exhumation history of the Altotiberina Fault (ATF), a representative example of crustal-scale active low-angle normal faulting in the Northern Apennines (Italy). Thermal maturity and thermochronological data yield similar burial histories but different exhumation patterns for the sedimentary successions in the hangingwall and the footwall of the ATF. Since 3.8 Ma, the ATF footwall has exhumed at rates of 0.90 mm a 1. Exhumation led to bending and deactivation of the ATF uppermost portion as a result of tectonic unloading and isostatic adjustment, followed by migration of extension and the development of a set of domino-like, east-dipping normal faults, rooting on the buried portion of the ATF. ATF activity and isostatic rebound exhumed Triassic rock units from depths of about 4 km. We suggest that isostatic instability is accommodated at shallow crustal levels, in a similar way to what is observed on larger structures at mid-low crustal levels
284 7 - PublicationRestrictedReply to Narkiewicz (2017) comment on “Thermal evolution of Paleozoic successions of the Holy Cross Mountains (Poland)”(2017-07)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; In this paper we reply to the criticisms advanced by Narkiewicz (2017) on the paper by Schito et al. (2017). We clarify the issues related to the stratigraphic and thermal maturity constraints used for reconstructing burial and thermal models of the two blocks of the Holy Cross Mountains. We also show how geological evidences brought by Narkiewicz (2017) as a proof of elevated Variscan heat flow are not conclusive or at least suggest the occurence of a localized thermal anomaly only along the area of the Holy Cross Fault. In the end, we performed new burial and thermal models in the Kielce region demonstrating that stratigraphic thickness variations between Schito et al. (2017) and Narkiewicz et al. (2010) produce only negligible differences in levels of thermal maturity of Paleozoic rocks. In addition, we outline that levels of thermal maturity for Silurian rocks can be matched only by using constant heat flow values through the Paleozoic and point to a decisive role for the absence of regional high Variscan heat flow in the area.326 5