...W. D. Keller; G. W. Viele; C. H. Johnson Abstract Arkansas novaculite in the Hot Springs-Little Rock area exhibits the texture, in scan electron micrographs, of a thermally metamorphosed rock formed ostensibly from cryptocrystalline chert. The stratigraphic formation, named Arkansas Novaculite...

...A. E. Beck Abstract Since it has been found that the heat flow along a borehole rarely deviates more than 20 percent from the mean equilibrium value and that formation thermal resistivities may vary by as much as an order of magnitude, the profile of temperature gradient versus depth is equivalent...

...D. J. Bachinski Abstract Thermal metamorphism of cupriferous iron sulfide deposits occurring in mafic volcanic rocks in the Notre Dame Bay area of Newfoundland results in conspicuous changes in ore and gangue mineral assemblages. Formerly chloritic and sericitic host rocks are represented...

... by transverse faults, deformed by longitudinal shear, affected by thermal metamorphism and by an early period of dynamothermal metamorphism. Silicate mineral assemblages of the country rocks indicate metamorphism at pressures in excess of 5 kilobars and temperatures from 525 degrees to 690 degrees C...

... lithosphere is perturbed, causing doming or swelling and eventual fracture and magmatism. It is also possible that kimberlite and carbonatite intrusions are a result of thermal perturbations that result when continental lithosphere overrides a chemical hot spot. The locations of chemical plumes may control...

...Gerhard Lagaly; Klaus Beneke; Armin Weiss Abstract Analytical composition, thermal analysis, and cation exchange reactions with organic cations are reported for the synthetic and natural layer silicate magadiite Na 2 Si 14 O 29 · 1l H 2 O. Thermal decomposition of magadiite depends upon...

... thermochemical (heat), piezochemical (shear), and possibly radiochemical (radiation) reactions. Energy for thermal alteration and destruction (conversion to amorphous carbon and to graphite) may be generated geothermally (related to sedimentary or tectonic overburden) or by igneous activity (volcanic...

...A. Hood; C. C. M. Gutjahr; R. L. Heacock Abstract A scale referred to as “Level of Organic Metamorphism” (LOM) describes how far the thermal metamorphism of sedimented organic matter has progressed during subsurface burial. It represents a single, continuous numerical scale which is applicable...

...TERRY W. OFFIELD Abstract High-altitude thermal-infrared images, taken at various times of the day over the Front Range and adjacent plains in Colorado, display many linear and circular topographic features. These features are enhanced by thermal shading effects and commonly are better displayed...

...V. Rajamani; C. T. Prewitt Abstract Natural pentlandite has a smaller cell dimension than the synthetic pentlandite of identical composition and shows a nonreversible thermal expansion after heating at moderately low temperatures. The reasons for the irreversible expansion have not been completely...

..., biotite, and sericite in varying proportions constitute the gangue.The ores have been subjected to dynamothermal-dynamic metamorphism. Effects of thermal metamorphism are noted locally. Textural features such as polygonization, equiangular triple-junction points in polycrystalline aggregates, annealing...

... oils undergo continuing alteration which ultimately affects their composition to a greater extent than does the character of the source material. Unmetamorphosed deeper reservoirs yield sweet, lighter crudes because of thermal alteration and deasphalting. Such crudes are also less likely to have...

...Wilson L. Orr Abstract Changes in sulfur content and sulfur-isotope ratios with “thermal maturation” have been studied using Big Horn basin (Wyoming) Paleozoic oils as examples of “single source” oils which have attained different stages of maturity as a result of variations in thermal history...

...D.J. Frank; J.R. Gormly; W.M. Sackett Abstract A series of long-term thermal cracking experiments at 400°C on n -octadecane and a comparison with previous experiments at higher temperatures established that temperature effects for 400°C and above are unimportant relative to the nature of the bonds...

...G. A. Chinner; J. S. Fox Abstract Thermal metamorphism GeoRef, Copyright 2004, American Geological Institute. 1974 ...