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1

Early Thermal History of Rhea: The Role of Serpentinization and Liquid State Convection

Czechowski L., Łosiak A.

Acta Geophysica

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2016

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Vol. 64, no. 6

2677--2716

EN

Early thermal history of Rhea is investigated. The role of the following parameters of the model is investigated: time of beginning of accretion, tini, duration of accretion, tac, viscosity of ice close to the melting point, η0, activation energy in the formula for viscosity, E, thermal conductivity of silicate component, ksil, ammonia content, XNH3, and energy of serpentinization, cserp. We found that tini and tac are crucial for evolution. All other parameters are also important, but no dramatic differences are found for realistic values. The process of differentiation is also investigated. It is found that liquid state convection could delay the differentiation for hundreds of My. The results are confronted with observational data from Cassini spacecraft. It is possible that differentiation is fully completed but the density of formed core is close to the mean density. If this interpretation is correct, then Rhea could have accreted any time before 3-4 My after formation of CAI.

2

Comparison of Early Evolutions of Mimas and Enceladus

Czechowski L., Witek P.

Acta Geophysica

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2015

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Vol. 63, no. 3

900--921

EN

Thermal history of Mimas and Enceladus is investigated from the beginning of accretion to 400 Myr. The numerical model of convection combined with the parameterized theory is used. The following heat sources are included: short lived and long lived radioactive isotopes, accretion, serpentinization, and phase changes. The heat transfer processes are: conduction, solid state convection, and liquid state convection. We find that temperature of Mimas’ interior was significantly lower than that of Enceladus. If Mimas accreted 1.8 Myr after CAI then the internal melting and differentiation did not occur at all. Comparison of thermal models of Mimas and Enceladus indicates that conditions favorable for the start of tidal heating lasted for a short time (~107 yr) in Mimas and for ~108 yr in Enceladus. This could explain the Mimas-Enceladus paradox. In fact, in view of the chronology based on cometary impact rate, one cannot discard a possibility that also Mimas was for some time active and it has the interior differentiated on porous core and icy mantle.

3

Thermal history and large scale differentiation of the Saturn’s satellite Rhea

Czechowski L.

Acta Geophysica

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2012

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Vol. 60, no. 4

1192-1212

EN

Thermal history of Rhea from the beginning of accretion is investigated. We developed a numerical model of convection combined with the parameterized theory. Large scale melting of the satellite’s matter and gravitational differentiation of silicates from ices are included. The results are confronted with observational data from Cassini spacecraft that indicate minor differentiation of the satellite’s interior. We suggest that partial differentiation of the satellite’s interior is accompanied (or followed) by the process of light fraction uprising to the surface. The calculation indicates that the partial differentiation of the matter of the satellite’s interior is possible only for narrow range of parameters. In particular, we found that the time from the formation of CAI (calciumaluminum rich inclusions in chondrites) to the end of accretion of Rhea is in the range of 3-4 My.

4

Hydrocarbon generation/expulsion modelling of the lower Paleozoic potential source rocks in the Gryfice and Kolobrzeg blocks (NW Poland)

Wróbel M., Kosakowski P., Poprawa P.

Geological Quarterly

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2010

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Vol. 54, No 2

183-196

EN

The lower Paleozoic source rocks in the offshore part of the Gryfice and Kolobrzeg blocks (NW Poland) were studied through geochemical data and numerical modelling. The geochemical study revealed a presence of effective source rocks in Caradocian strata, but with low hydrocarbon potential. The remaining lower Paleozoic source rock horizons were not documented by core samples. The timing of hydrocarbon generation and expulsion was modelled for the K1-1/86 and L2-1/87 boreholes located in the Gryfice and Kolobrzeg blocks, respectively. 1-D and 2-D modelling indicated that in the Kolobrzeg Block the onset of petroleum generation occurred at the end of the Silurian and the beginning of the Devonian. Source rocks in the Gryfice Block reached the early stage of oil generation at the beginning of the Permian and generation processes were completed by the end of the Triassic. Migration of hydrocarbons from source rocks began in the Carboniferous in both the Gryfice and Kolobrzeg blocks and lasted to the end of the Mesozoic. During hydrocarbon migration, an intensive dispersion process was observed, caused by leaking along the fault planes. The modelling revealed that hydrocarbons may have accumulated in Devonian reservoirs. The lack of any discovered accumulations could be the result of hydrocarbon dispersion caused by tectonic deformation and intense vertical fault block movements.

5

Burial and thermal history of the Polish part of the Baltic region

Wróbel M., Kosakowski P., Poprawa P.

Geological Quarterly

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2010

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Vol. 54, No 2

131-142

EN

The burial history and thermal evolution of the western part of the Baltic region was reconstructed by means of 1-D modelling for eight boreholes penetrating the lower Paleozoic succession. The Neoproterozoic rifting presumably caused elevation of heat flow, while Cambrian to Mid Ordovician post-rift thermal sag of the Baltica passive margin led to systematic decrease of heat flow with time. Development of the Late Ordovician to Silurian flexural foredeep of the Caledonide collision zone was associated with intensive subsidence, a high rate of sediment deposition and rapid burial of the Upper Cambrian and/or Tremadocian, Upper Ordovician and lower Silurian source rocks, presumably sufficient for the early stage of oil generation. After post-Caledonian Early Devonian uplift, the western Baltic region was subject to Early Devonian to early Carboniferous subsidence and deposition, leading to further burial of the source rocks. Together with elevated heat flow, characteristic of the Variscan broad foreland, this caused further source rocks maturation and hydrocarbon generation. Late- to post-Variscan uplift and erosion (late Carboniferous to late Permian) resulted in complete removal of the Middle Devonian to lower Carboniferous strata and development of the major regional unconformity. During late Permian to Cretaceous time the western part of the Baltic region constituted an eastern flank of the Polish Trough, with the main phases of subsidence and burial during late Permian-Early Triassic time, related to rifting in the Polish Trough, and during Late Cretaceous time, related to the compressional regime. Maturity profiles in boreholes from the vicinity of the studied boreholes indicate the presence of a late Mesozoic (Late Cretaceous?) positive thermal event, causing further maturation of the source rock.

6

Uniform parameterized theory of convection in medium sized icy satellites of Saturn

Czechowski L.

Acta Geophysica

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2009

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Vol. 57, no. 2

548-566

EN

We develop a parameterized theory of convection driven by radiogenic and tidal heating. The tidal heating depends on eccentricity e of a satellite's orbit. Using parameterized theory we determine the intensity of convection as a function of e and satellite's properties. The theory is used for 6 medium sized satellites of Saturn. We find that endogenic activity on Tethys and Dione is possible if e exceeds some critical values e[cr]. For Enceladus, e was probably close to the present value for billions of years. We cannot find constrains for e of Mimas and Iapetus. The theory successfully predicts the possibility of present endogenic activity in Dione and rules out such activity in Tethys. Both these facts were recently confirmed by Cassini mission.

7

Structural and textural evolution of zirconia nanocrystals induced by thermal treatment

Adamski A., Jakubus P., Sojka Z.

Materials Science Poland

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2008

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Vol. 26, No. 2

373--380

EN

Nanometric tetragonal and monoclinic zirconia was synthesized from zirconyl chloride by the modified forced hydrolysis method. Phase transitions and morphological changes accompanying zirconia calcination in the temperaure range 600-1000 °C were studied by XRD, HR-TEM techniques and N2-porosimetry. Ageing of the amorphous hydrous zirconia at 100 °C for 48 h in the mother solution and its subsequent calcination at 600 °C for 6 h strongly favoured formation of single-phase tetragonal ZrO2 of the thermal stability enhanced by 250 °C. Influence of the calcination temperature on phase composition, grain size, grain boundaries and pore structure of the resultant ZrO2 material was analyzed.

8

Two models of parameterized convection for medium-sized icy satellites of Saturn

Czechowski L.

Acta Geophysica

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2006

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Vol. 54, no. 3

280-302

EN

A parameterized theory of convection is developed for 6 medium-size icy satellites (MIS) of Saturn. It is an extension of the research concerning the Mimas -Enceladus paradox. Two parameterizations of dimensionless temperature are used in the model and a new constrain for tidal heating is included. It is found that the basic results of the model are independent of particulars of the parameterizations. The new constrain considerably reduces the space of possible values of the material parameter of satellites but the two basic conclusions are unchanged, i.e.: (a) the thermal state of the considered MIS can be explained in the frame of the uniform model that includes radiogenic and tidal heating; (b) the theory indicates that endogenic activity of some MIS was (or is) a result of a specific ‘excited’, high temperature state of a given satellite. The theory could be also used for estimation of tidal heating.

9

Potencjał naftowy utworów dolomitu głównego w strefie Kamienia Pomorskiego. Cz. 2, Analiza ropotwórczości

Kosakowski P., Burzewski W., Kotarba M. J.

Przegląd Geologiczny

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2003

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Vol. 51, nr 8

663-672

PL

Wyodrębniony w basenie dolomitu głównego element strukturalny platformy węglanowej Kamienia Pomorskiego jest okonturowanym facjalnie obszarem zbioru akumulacyjnego występujących tam złóż naftowych. Z tego względu obszar ten został wybrany do analizy porównawczej wytworzonego potencjału węglowodorowego w stosunku do wielkości akumulacji. Wyliczony metodą modelowania numerycznego potencjał węglowodorowy 2,5 do 8,8 kg HC/m3 skały macierzystej w odniesieniu do jej miąższości daje wielkość jednostkowego powierzchniowego potencjału węglowodorowego w przedziale od 11 do 163 kg HC/m2 powierzchni strukturalnej dolomitu głównego w strefie platformy węglanowej Kamienia Pomorskiego. Wielkości te kwalifikują system naftowy platformy węglanowej w klasie basenów naładowanych, z 16% wykorzystaniem wytworzonego potencjału ekspulsji w wielkości akumulacji złóż platformy węglanowej Kamienia Pomorskiego.

EN

The structural element of the Kamień Pomorski carbonate platform, separated from the Main Dolomite basin, is facially contoured with oil accumulations. For this reason the area was selected for a comparative analysis of hydrocarbon potential and the volume of accumulation. Hydrocarbon potential (2.5 to 8.8 kg HC/m of source rock) was calculated in relation to the thickness of the source rock by a numerical modelling method. On this basis the hydrocarbon potential was estimated. It ranges from 11 to 163 kg HC/m in the structural area of the Main Dolomite strata of Kamień Pomorski carbonate platform. With such parameters, the oil system in the carbonate platform could be classified as normally charged basin, with 16% efficiency of hydrocarbon potential in the oil accumulations of Kamień Pomorski carbonate platform

10

Thermal evolution of solid targets irradiated by pulsed plasma beams

Szymczyk W., Piekoszewski J., Werner Z., Szyszko W.

Nukleonika

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2002

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Vol. 47, nr 4

163-166

EN

Thermal evolution of various targets irradiated with high intensity pulsed ion or plasma beams was determined by computer simulation i.e. by solving numerically one dimensional heat flow equation. The calculations were carried out using the adopted ETLIT computer code (Energy Transport in Laser Irradiated Targets) based on Finite Element Method. The surface temperature, melt depth and liquid duration were computed as a function of pulse energy density, pulse duration, melting temperature and thermal diffusivity of a given material. In particular, some examples are shown for such materials as: Cu, Al, Zn, Fe, Ti, Mo, W, and Al2O3. Various practical aspects of the obtained results are discussed, with a special attention given to less or no intuitively predictable dependencies.