Recent Studies of the Geothermics of the Sedimentary Basins

 We have summarized and critically reviewed Polish well  temperature logs in the cratonic area and in the accreted terranes to the south west. The analysis of this data and modeling of the crustal temperatures shows evidence of extensive crustal-mantle warming in the area between the Sudets to the south and the TESZ (Trans-European Suture Zone) to the north. The change in heat flow is over 100% when compared with the craton and well above the uncertainty limits. Heat flow in anomalous zone is also higher  by some 25% than in the Sudets. The axis of the anomaly is approximately aligned with the Dolsk Fault and Variscan deformation front. Low crustal/mantle temperatures derived from the relationship between temperature and Pn velocities (as high as 8.4 km/s) are at odds with high crustal temperatures calculated from surface heat flow, seismic velocity based heat generation models and thermal conductivity with depth. High heat flow (Variscan platform) zone and related high temperatures of the crust coincides with relatively low crustal thickness (30-35km). Opposite is the case for the low heat flow zone (45-50km). High heat flow of the thin crust and low heat flow of the thick crust with no major changes in elevation is supported by simple isostatic balance model. Crustal heat generation can explain some of the high flow in the zone characterized  by thick meta-sediments reaching up to 20 km depth, however, it is far from explaining high heat flow zone in the areas of Variscan crust and in the transition zone into a cold craton . New modeling of heat flow using 2D inversions and strongly based on new seismic results shows that the contrast (some 15mW/m²) in mantle heat flow is required to explain observed changes. High mantle heat flow (40 mW/m²) is likely to occur in the high heat flow zone while cold crust and cold and high density mantle (mantle heat flow of 25 mW/m²) is characteristic for the craton. The Teisseyre-Tornquist Zone (TTZ),  in Poland is showing as  relatively cold area.

 Recent results were published in Physics and Chemistry of the Earth 28 (2003) p. 375-391 in Geological Quarterly 2004 number 1. v.48. p 1-14

Recent Methane Hydrate Studies

Regional studies of methane hydrate stability has been conducted for the northern Canadian basins (off shore and on shore) and the Atlantic oceanic margin of Canada. Estimates of the methane volume (hydrate based) for Canada has been done (AAPG Bulletin Vol. 85, July 2001). Detailed studies of well logs in the Beaufort McKenzie and Sveredrup basins has been presented  (Majorowicz et al 2000, Natural Resources Research Vol. 9, Number 1 and Number 3, and Vol.11 Number 2, June 2002).

The study of natural gas hydrate stability in the East Coast Offshore-Canada has been recently completed. The maps of thickness of the methane hydrate stability zone have been shown for the Nova Scotia Shelf, Grand Banks and Labrador-offshore (Majorowicz and Osadetz, Natural Resources Research, Vol. 12, No.2, June 2003, p. 93-104).