Thermal alteration index

Staplin, F. Determination of thermal alteration index from color of exinite (pollen, spores), in How to assess maturation and paleotemperatures, (eds. Staplin, F. L., et al.) SEPM Short Course 7, p. 91, Tulsa OK, SEPM 1982... 

The second important point is that not all samples contain vitrinite. Pre-Devonian samples do not contain vitrinite since higher plants did not evolve until around this time and vitrinite is derived from higher plant remains. However, there are a number of alternative maturity scales that can be used. For example, the thermal alteration index (Staplin, 1969) and spore coloration index (Burgess, 1974) have been used... 

Temperature is the main "driving force" of the geochemical pro esses to a point that a thermal alteration index (an indication of the maximum temperature the sample has reached) can be used to say if the organic matter is mature to produce oil or gas. 

Thermal Alteration Index. This index, of a very empiric nature, tries to define the maximum temperature reached by the rock in terms of color and preservation of the sample (for more details see e.g. Correia (34)). The use of this index has been very useful in studies with the Irati F. to detect temperature effects due to the diabase intrusion. Used as a stratigraphic function in the column CERI-1 it was possible to detect a heat effect on the top of the lower... 

Temperature is a fundamental parameter that definitely influen ces the maturation of sediments. This has been shown empiricalyari T laboratory simulations use it as the "driving force" to induce maturation. In this way, the use of the thermal alteration index in geological materials allows one to qualify (37) source rocks as imature (.temperature below 609C), mature (able to produce oil -if the sediment reached temperatures of 60-1509C) and senile - ja ble to produce gas if the temperature surpassed 1509C. It must be always kept in mind that these transformations occurred along millions of years, and, consequently, all tentatives to simulate these processes in laboratory suffer a severe criticism of their validity. 

Rock-Eval Tmax (°C) thermal alteration index (TAI)... 

Thermal Properties. Thermal properties include heat-deflection temperature (HDT), specific heat, continuous use temperature, thermal conductivity, coefficient of thermal expansion, and flammability ratings. Heat-deflection temperature is a measure of the minimum temperature that results in a specified deformation of a plastic beam under loads of 1.82 or 0.46 N/mm (264 or 67 psi, respectively). Eor an unreinforced plastic, this is typically ca 20°C below the glass-transition temperature, T, at which the molecular mobility is altered. Sometimes confused with HDT is the UL Thermal Index, which Underwriters Laboratories estabflshed as a safe continuous operation temperature for apparatus made of plastics (37). Typically, UL temperature indexes are significantly lower than HDTs. Specific heat and thermal conductivity relate to insulating properties. The coefficient of thermal expansion is an important component of mold shrinkage and must be considered when designing composite stmctures. 

A method for determining the alteration of the refractive index of a medium as a result of the temperature rise in the path of a beam of coherent light absorbed by the medium. Thermal lensing can also occur with pigmented proteins, and this phenomenon can influence the accuracy of concentration gradient measurements in small aperture flow cuvettes as well as in ultracentrifugation. 

When a solid body is made to absorb heat, we have seen that its temperature, and its volume, and hence also its specific gravity, are aU altered. At the same time, a great number of the other physical properties of the body are changed for example, its optical properties (refractive index and reflectivity), its electrical and thermal conductivity, etc. AU these properties vary continuously with the temperature, so that we have a continuously changing series of intermediate states of the body between any two temperatures. There is a temperature for every body at which this continuous change of the physical properties ceases, viz. the temperature at which the body changes from the solid to the liquid state. This process... 

Physical Hygroscopic differential Thermal stability Cold flow or creep distortion Refractive index may be altered Reflective index may be altered... 

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