Heating during thrust faulting in the rocky mountains: friction or fiction?

doi:10.1016/0040-1951(83)90075-6

Tectonophysics

Volume 95, Issues 3–4, 10 June 1983, Pages 309-328

https://doi.org/10.1016/0040-1951(83)90075-6 Get rights and content

Abstract

Measurement of the levels of organic maturation below and within shear zones of thrust faults in the Rocky Mountains has revealed no general thermal metamorphism that can be attributed to faulting, with the exception of very localized areas. With few exceptions the vitrinite reflectance values obtained are in the range expected if the maximum level of organic maturation was produced as a result of increasing temperature during progressive burial accompanying sedimentation. Only at Marias Pass evidence has been found to suggest additional maturation as a result of post-orogenic burial below the thrust sheets. Anomalously high vitrinite reflectances obtained from the Lewis thrust, McConnell thrust, Coleman thrust and two unnamed thrusts, are restricted to very narrow films immediatly adjacent to, or within the shear zone which, considering any reasonable thermal conductivity, indicates elevated temperatures were very short lived. The anomalously high vitrinite reflectances within these films, when compared to laboratory heated coals, suggest temperatures in the order of 350°-650°C were locally generated during faulting. Such high temperatures are considered to have been generated during stick-slip faulting at macro-asperities or at ramps on the fault plane where local, and possibly transient, high frictional stresses existed. The absence of evidence for extensive frictional heating supports previous arguments that stable-sliding and/or low frictional stress must exist during thrusting.

References (52)

A.R. Allen
Mechanism of frictional fusion in fault zones
J. Struct. Geol.
(1979)
T.K. Ghosh
Reflectance of Himalayan coals
Fuel
(1970)
J.T. McCartney et al.
Classification of coals according to degree of coalification by reflectance of the vitrinite component
Fuel
(1972)
H.E. Moore et al.
Experimental thermal fragmentation in relation to seismic faulting
Tectonophysics
(1978)
L.J. Sydora et al.
Model calculations of the thermal fields of subducting lithospheric slabs and partial melting
Tectonophysics
(1980)
M.N. Toksöz et al.
Modelling of temperatures in continental convergence zones
Tectonophysics
(1977)
A. Beech et al.
Fluid transport and shear zones at Scourie Scotland: evidence of overthrusting
Contrib. Mineral. Petrol.
(1972)
N.H. Bostick
Time as a factor in thermal metamorphism of phytoclasts (coaly particules)
N.H. Bostick
Microscopic measurements of the level of catagenesis of solid organic matter in sedimentary rocks to aid in exploration for petroleum and to determine former burial temperatures, a review
Soc. Econ. Paleontol. Mineral., Spec. Publ.
(1979)
N.H. Bostick et al.
Gradients of vitrinite reflectance and present temperatures in the Los Angeles and Ventura Basins

F.P. Bowden et al.

The friction and lubrication of solids

R.M. Bustin

Oxidation characteristics of some sheared coal seams of the Mist Mountain Formation, southeastern Canadian Cordillera

R.M. Bustin et al.

Implications of coalification levels. Eureka Sound Formation, northeastern Arctic Canada

Can. J. Earth Sci.

(1977)

R.K. Cardwell et al.

Frictional heating on a fault zone with finite thickness

Geophys. J. R. Astron. Soc.

(1978)

J.R. Castano et al.

Interpretation of vitrinite reflectance measurements in sedimentary rocks and determination of burial history using vitrinite reflectance and authigenic minerals

D. Chandra

Reflectance and microstructure of weathered coals

Fuel

(1962)

D. Chandra

Use of reflectance in evaluating temperatures of carbonized or thermally metamorphosed coals

Fuel

(1965)

D. Chandra

Reflectance of coals carbonized under pressure

Econ. Geol.

(1965)

M.O. Childers

Structure and stratigraphy of the southwest Marias Pass area, Flathead Country, Montana

Geol. Soc. Am. Bull.

(1963)

R.R. Dutcher et al.

Carbonaceous materials as Indicators of Metamorphism

Geol. Soc. Am., Spec. Pap.

(1974)

I.F. Ermanovics et al.

An occurrence of Archean pseudotachylite from southeastern Manitoba

Can. J. Earth Sci.

(1972)

M. Friedman et al.

Glass indurated quartz gouge in sliding friction experiments of sandstone

Geol. Soc. Am. Bull.

(1974)

T.K. Ghosh

A study of temperature conditions at igneous contacts with certain Permian coals of India

Econ. Geol.

(1967)

P.E. Gretener

On the character of thrust faults with particular reference on the basal tongues

Bull. Can. Pet. Geol.

(1977)

P.A. Hacquebard et al.

Rank studies of coals in the Rocky Mountains and Inner Foothills Belt Canada

Hendrickson

Cited by (71)

Palaeo-thermal history of the Blanice Graben (the Bohemian Massif, Czech Republic): The origin of anthracite in a late-Variscan strike-slip basin
2022, International Journal of Coal Geology
Citation Excerpt :
Although temperature has generally been considered to be a triggering factor for coalification, which influences the coalification stage gradually, the frictional heat generated by shearing events in tectonically active terrains have also been shown to be a physical force capable of enhancing the coalification rate (Taylor et al., 1998; Cao et al., 2009) and to promote a significant increase in optical reflectance and bireflectance of vitrinite (Stone and Cook, 1979; Teichmüller et al., 1979; Frey et al., 1980; Hower and Davis, 1981; Teichmüller, 1987; Levine and Davis, 1989; Suchy et al., 1997; Ghosh et al., 2018; see also Yu et al., 2022 for a review). Sharp but localized increases in coal rank up to the anthracite stage have sometimes been observed adjacent to or within sheared fault planes, and interpreted as a consequence of short-lived high temperatures (350–650 °C) generated by frictional heating during faulting (Teichmüller and Teichmüller, 1966; Bustin, 1983; Bustin and England, 1990). More recent experimental studies have also proven that coal, when exposed to frictional heat ranging from 26 °C to >500 °C, can mature extremely rapidly up to the meta-anthracite rank, in only ∼9–11 s.
Coal petrology data and vitrinite reflectance modelling were combined with micro-geochemical and fluid inclusion analyses of coal mineralization and apatite fission track analysis (AFTA) of coal-bearing sediments to constrain the thermal history of the Blanice Graben, a narrow, nearly 150-km long, late-Variscan strike-slip basin filled with Permo-Carboniferous continental coal-bearing deposits. The vitrinite reflectance modelling and the ranking of coals, which increased along the meridional axis of the graben from bituminous coals (R_r ∼ 0.70%) to high-rank anthracites (R_r = 2.85–4.77%), provide evidence of maximum palaeo-temperatures ranging from about 120–145 °C to 310–390 °C. This corresponds to the diagenetic realm in the north of the graben that graded to high-grade anchizonal to low-epizonal metamorphic conditions in the south. The present level of coalification resulted from the Permian burial, 2500–5000 m thick, which aggregated under a high geothermal gradient (∼ 90 °C/km). In central and southern relics of the graben, however, specific microscopic features of coals and fluid inclusion and chlorite thermometry suggest that the anthracite rank was attained by the combined effect of a stratigraphic burial, a regional discharge of ∼300 °C hot, mineralized fluids that ascended along faults into buried coal-bearing strata and an intense Permian faulting and shearing of coal seams, which collectively contributed to the anthracitization process. The heat source, promoting high geothermal gradient and circulation of hot fluids through the coal-bearing sediments, was probably associated with a mantle magma chamber hidden deeply below the graben and manifested at current errosional level by ∼303 and ∼ 270 Ma old microdiorite dykes. Similar dramatic geothermal settings, characterized by elevated geothermal gradients, localized fault-controlled incursions of hot hydrothermal solutions, and rapid coalification of peat layers at relatively shallow depths of burial, dominated in many late Variscan coal-bearing basins during a period of post-collisional extension at ∼315–280 Ma. The AFTA method, applied to sedimentary apatites, provides evidence that following the climax of the Variscan orogeny, the Blanice Graben coal-bearing deposits were rapidly uplifted and, throughout the Mesozoic and Cenozoic times, they experienced only prolonged slow cooling (0.46–0.54 °C/My) and moderate burial temperatures of 50–70 °C. Its final ascent towards the present-day erosional surface occurred during a period of accelerated uplift that has affected the Bohemian Massif since the Oligocene.
Deformation-related coalification: Significance for deformation within shallow crust
2022, International Journal of Coal Geology
Citation Excerpt :
It has long been recognized that long tectonic evolution and sedimentary burial process of the coal measures have produced the adequate temperature and work time to catalyze the transformation process of organic macromolecules (Bustin, 1982; Bustin, 1983). Before the 21st century, there was speculation on whether tectonic stress could change the chemical structure of coal (Bustin, 1983; England and Bustin, 1986; Suchy et al., 1997). Coal geology research has demonstrated significant transitions in the physical structures of coal, for example, the pore-fracture system (Laubach et al., 1998), optical properties of vitrinite (Levine and Davis, 1989; Ross and Bustin, 1997; Suchy et al., 1997), and matrix deformations (Frodsham and Gayer, 1999; Li, 2001).
With a low mechanical strength and high Poisson's ratio, coal can exhibit brittle or ductile deformation when exposed to lower levels of stress, strain rate, pressure, and temperature compared to the adjacent sedimentary rocks (sandstone, mudrock, and carbonate). The physical and optical properties of deformed coals have been extensively examined. However, it is still unclear if within the shallow crust, tectonic stresses can enhance the coalification and how the coal organic structure responds to ductile deformation. Here, dynamic-related coalification was reviewed to identify the significance of ductile deformation within the shallow crust. Compared with the brittle and transition stages, the dynamic-related coalification initiated within the ductile deformation could also exert a more substantial impact, resulting in a distinct evolution such as enhanced structural alignment, increased curvature in aromatic molecules, higher aromaticity, and generation of secondary defects. Although these alterations are similar to those resulting from normal thermometamorphism, their patterns are influenced by the stress mode and tectonic exposure, which was related to the host basins. Either tension or extrusion stresses under a high strain rate (corresponding to normal or high-angle reverse faults) are favorable for brittle deformation, where the dynamic-related coalification was presented as a stress degradation process. However, ductile deformation (or even rheology) was produced from compressive-stress, compressive-shear stress, or pure shear stress accompanying low strain rates (corresponding to the nappe, layer slip, and strike-slip faults). There, the deformation-related coalification was promoted to a greater extent and was present as stress condensation. Thus, the deformation extent of coal and the accompanying deformation-related coalification is of significance for identifying the ductile deformation within the shallow crust. The outcome of this paper can be applied to the geological analysis of coalfield structure in tectonically complex regions.
Stress degradation mechanism of coal macromolecular structure: Insights from molecular dynamics simulation and quantum chemistry calculations
2021, Fuel
The shear action caused by tectonic stresses deforms and destroys the coal macrostructure and significantly affects the coal macromolecular structure. To study the degradation mechanism of the macromolecular structure of low-rank coal during shearing, the macromolecular structure model of Wender coal was selected in this study. Forty molecules of this structure were used to construct a polymer cell. Shearing simulations were performed using Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) software, and bond strength was determined using Gaussian software. Two chemical bond breakage types were observed: tensile break and shear break. The former is controlled by the bond's position and strength, while the latter is controlled by the bond's position and angle strength. The mechanism of tensile break is different from that of shear break. The former tends to occur when the bond rotates clockwise around the point of action, towards the shear action direction (X axis positive direction), and the rotation angle is between 0° and 90°. The latter easily occurs when the bond rotates clockwise around the point of action, towards the shear action direction (X axis positive direction), and the rotation angle is between 90° and 180°. Small molecules, such as CH₄, are produced by the shear action, partially revealing the excess coalbed methane eruption mechanism of coal and gas outburst. The shear action increases the order degree and stratification of the coal molecular structure by breaking and cutting side chains and bridge bonds, promoting the evolution of the coal rank.
Gas generation mechanisms of bituminous coal under shear stress based on ReaxFF molecular dynamics simulation
2021, Fuel
Although research on the relationship between coal functional groups and tectonic stress has made great progress in recent years, the evolution of the morphology and chemical structures of coal macromolecules under tectonic stress is still unclear. We used reactive force field molecular dynamics (ReaxFF MD) simulations to explore the gas generation mechanisms of high-volatile bituminous coal model under shear stress. Several interesting results were found. First, in the absence of frictional heat, shear stress can act on the macromolecular structures of coal directly and generate gases, such as CH₄, CO₂, H₂O, H₂, and CO. Second, under the action of shear stress, coal macromolecular structures will generate a variety of free radicals, such as OH, H, CH₃, and many small free radical fragments or monocyclic radicals. These detached free radicals may combine with each other or attach to other structures to promote further reactions. Third, in the entire macromolecular network, many components may participate in the reactions as “catalysts”, providing conditions for the contact of various small free radicals. For the first time, we have obtained direct simulation evidence of the gas generation mechanisms of coal via mechanolysis instead of relying on frictional heat. These results are a beneficial supplement to understand the coalification process.
Macromolecular transformations for tectonically-deformed high volatile bituminous via HRTEM and XRD analyses
2020, Fuel
Coalbed methane reservoir properties of tectonically deformed coals (TDCs) vary greatly in comparison to unaltered coals. These differences are attributed, in part, to their macromolecular transformations. The structure of different TDCs at various distances from a fault plane was evaluated using image analysis of aromatic fringes from HRTEM micrographs, and from XRD data. The distribution of fringe length, orientation, stacking, and curvature, were quantified to establish the structural organization. From the fringe length, orientation, and XRD data, two deformation stages were identified a) a weak deformation stage (–cataclastic–schistose–scaly) and b) a strong deformation stage (–wrinkled–mylonitic). In the weak deformation stage, the fringe length distribution was consistent, however the strong deformation coals had longer fringes. The majority (94–98%) of the aromatic fringes were individual layers for both stages. There was a significant improvement in the structural alignments however with strong deformation. The common statement that tectonic stress enhances the stacking of the aromatic clusters (and thus perhaps the graphitization ability) was not observed here. Rather, the enhancement in order was limited to the strong deformation stage. The aromatic fringes of the strong deformation coals had greater curvature extents. The XRD data also supported increased organization (lower d₀₀₂ values) with strong deformation. These observations indicate there was an improvement in the basic structural unit from poorly ordered to more ordered that occurred in the strong deformation stage. These transformations are likely to impact the coalbed methane production and methane behaviors.
Stress response of noncovalent bonds in molecular networks of tectonically deformed coals
2019, Fuel
Investigations on macromolecular evolution of tectonically deformed coals are of great theoretical and practical significances for the coal safe production and coalbed methane exploitation. Alteration of covalent bonds in rigid coal carbon skeletons was studied extensively, while insufficient attention was paid to the variation of noncovalent bonds in macromolecular networks. In present study, some insights about stress response of noncovalent bonds are given by investigating a primary coal and six typical tectonically deformed coals collected around a fault structure. Self-associated n-mers (n > 3), OH-ether, cyclic OH, COOH dimers, OH-SH and OH-N are all disrupted by tectonic stress, which is partially resulted from dissociation of functional groups. Conversely, amount of OH-π is in an increasing trend, indicating that there is a transformation between OH-π and other hydrogen bonds. In general, the total content of hydrogen bonds generally decreases from primary coal to granulitic coal, and then slightly increases from scaly coal to wrinkle coal, which is ascribed to the increase of OH-π transformed from other hydrogen bonds. Furthermore, −ΔH_total and −ΔH_av both decrease with the increasing deformation intensity even in scaly and wrinkle coals with slightly increasing total content of hydrogen bonds. While, the amount of ππ bonds increases with enhancement of coal deformation intensity (especially in brittle-ductile and ductile deformed coals), indicating that free molecules liberated by disruption of hydrogen bonds and ππ bonds are rearranged into a more stable, stacked and ordered configuration accompanied by the formation of new noncovalent bonds.

View all citing articles on Scopus

View full text

Heating during thrust faulting in the rocky mountains: friction or fiction?

Abstract

J. Struct. Geol.

Fuel

Fuel

Tectonophysics

Tectonophysics

Tectonophysics

Fluid transport and shear zones at Scourie Scotland: evidence of overthrusting

Contrib. Mineral. Petrol.

Time as a factor in thermal metamorphism of phytoclasts (coaly particules)

Microscopic measurements of the level of catagenesis of solid organic matter in sedimentary rocks to aid in exploration for petroleum and to determine former burial temperatures, a review

Soc. Econ. Paleontol. Mineral., Spec. Publ.

Gradients of vitrinite reflectance and present temperatures in the Los Angeles and Ventura Basins

The friction and lubrication of solids

Oxidation characteristics of some sheared coal seams of the Mist Mountain Formation, southeastern Canadian Cordillera

Implications of coalification levels. Eureka Sound Formation, northeastern Arctic Canada

Can. J. Earth Sci.

Frictional heating on a fault zone with finite thickness

Geophys. J. R. Astron. Soc.

Interpretation of vitrinite reflectance measurements in sedimentary rocks and determination of burial history using vitrinite reflectance and authigenic minerals

Reflectance and microstructure of weathered coals

Fuel

Use of reflectance in evaluating temperatures of carbonized or thermally metamorphosed coals

Fuel

Reflectance of coals carbonized under pressure

Econ. Geol.

Structure and stratigraphy of the southwest Marias Pass area, Flathead Country, Montana

Geol. Soc. Am. Bull.

Carbonaceous materials as Indicators of Metamorphism

Geol. Soc. Am., Spec. Pap.

An occurrence of Archean pseudotachylite from southeastern Manitoba

Can. J. Earth Sci.

Glass indurated quartz gouge in sliding friction experiments of sandstone

Geol. Soc. Am. Bull.

A study of temperature conditions at igneous contacts with certain Permian coals of India

Econ. Geol.

On the character of thrust faults with particular reference on the basal tongues

Bull. Can. Pet. Geol.

Rank studies of coals in the Rocky Mountains and Inner Foothills Belt Canada