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Thermal Indicator (thermal + indicator)

Distribution by Scientific Domains

Earth and Environmental Science	50%

Selected Abstracts

Low-temperature single crystal reflection spectra of forsterite

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006
H. Suto
ABSTRACT The infrared reflectivities of crystalline forsterite (Mg2SiO4) were measured for the temperature range 295,50 K for each crystal axis, between wavenumber 5000 and 100 cm,1. The reflection spectra show clear dependence of temperature; most of the bands become more intense, sharper and their peak positions shift to higher wavenumber with decreasing temperature. Reflection spectra were fitted with dispersion formula of damped oscillator model of the dielectric constants and the oscillator parameters in the model were derived. The absorption spectra of forsterite particle are calculated with the derived dielectric constants to show that the forsterite features are good thermal indicator for cold temperature range below 295 K. [source]

Pulmonary artery blood temperature and the measurement of cardiac output by thermodilution

ANAESTHESIA, Issue 6 2002
S. F. Moise
Summary Thermodilution cardiac output measurement assumes that the temperature within the pulmonary artery is stable during the measurement period. This may not be achieved in clinical practice because of temperature changes that are not solely produced by the thermal indicator. Such temperature changes constitute thermal noise. Thermal noise and how it may interfere with measurement is discussed with reference to both the injectate and the thermal filament methods of thermodilution cardiac output measurement. [source]

Unravelling the multi-stage burial history of the Swiss Molasse Basin: integration of apatite fission track, vitrinite reflectance and biomarker isomerisation analysis

BASIN RESEARCH, Issue 1 2006
Martin Mazurek
ABSTRACT A complex basin evolution was studied using various methods, including thermal constraints based on apatite fission-track (AFT) analysis, vitrinite reflectance (VR) and biomarker isomerisation, in addition to a detailed analysis of the regional stratigraphic record and of the lithological properties. The study indicates that (1) given the substantial amount of data, the distinction and characterisation of successive stages of heating and burial in the same area are feasible, and (2) the three thermal indicators (AFT, VR and biomarkers) yield internally consistent thermal histories, which supports the validity of the underlying kinetic algorithms and their applicability to natural basins. All data pertaining to burial and thermal evolution were integrated in a basin model, which provides constraints on the thickness of eroded sections and on heat flow over geologic time. Three stages of basin evolution occurred in northern Switzerland. The Permo-Carboniferous strike,slip basin was characterised by high geothermal gradients (80,100°C km,1) and maximum temperature up to 160°C. After the erosion of a few hundreds of metres in the Permian, the post-orogenic, epicontinental Mesozoic basin developed in Central Europe, with subsidence triggered by several stages of rifting. Geothermal gradients in northern Switzerland during Cretaceous burial were relatively high (35,40°C km,1), and maximum temperature typically reached 75°C (top middle Jurassic) to 100°C (base Mesozoic). At least in the early Cretaceous, a stage of increased heat flow is needed to explain the observed maturity level. After erosion of 600,700 m of Cretaceous and late Jurassic strata during the Paleocene, the wedge-shaped Molasse Foreland Basin developed. Geothermal gradients were low at this time (,20°C km,1). Maximum temperature of Miocene burial exceeded that of Cretaceous burial in proximal parts (<35 km from the Alpine front), but was lower in more distal parts (>45 km). Thus, maximum temperature as well as maximum burial depth ever reached in Mesozoic strata occurred at different times in different regions. Since the Miocene, 750,1050 m were eroded, a process that still continues in the proximal parts of the basin. Current average geothermal gradients in the uppermost 2500 m are elevated (32,47°C km,1). They are due to a Quaternary increase of heat flow, most probably triggered by limited advective heat transport along Paleozoic faults in the crystalline basement. [source]

Tectono-thermal Evolution in the Bachu Uplift, Tarim Basin, China

ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 5 2010
QIU Nansheng
Abstract: The thermal evolution of source rocks in the Paleozoic has long been a problem to petroleum exploration in the Bachu uplift, Tarim basin, since the thermal history in the Paleozoic could not be rebuilt objectively due to lack of effective thermal indicators in the Lower Paleozoic successions. The apatite and zircon (U-Th)/He thermochronometry can be used as a new kind of technique to study the thermal history and tectonic uplift of sedimentary basins. Based on the measured apatite and zircon (U-Th)/He ages, apatite fission track data and equivalence vitrinite reflectance (%EVRo), the tectonothermal histories in 5 wells of the Bachu uplift were modeled. The modeling results show that there was relatively high gradient at the Early Paleozoic in the Bachu uplift and it decreased gradually during the entire Paleozoic: 33,35°C/km in the Cambrian-Ordovician, 32,33°C/km in the Silurian-Devonian, 30,32°C/km at the end of Carboniferous and 27.5,31°C/km at the end of Permian. Therefore, the thermal history can be modeled by combining multiple thermal indicators of AFT, (U-Th)/He ages and EVRo data. Especially, this provides a new method to rebuild the thermal history for the Low Paleozoic carbonate successions in the Tarim Basin. [source]