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Earthquakes are frictional instabilities caused by the shear stress decrease, that is, dynamic weakening, of faults with slip and slip rate. During dynamic weakening, shear stress depends on slip, slip rate, and temperature, according to constitutive laws governing the earthquake rupture process. In the laboratory, technical limitations in measuring temperature during frictional instabilities inhibit the investigation and interpretation of shear stress evolution. Here we conduct high velocity friction experiments on calcite‐bearing simulated faults, both on bare‐rock and on gouge samples, at 20–30 MPa normal stress, 1–6 m/s slip rate and 1–20 m total slip. Seismic slip pulses are reproduced by imposing boxcar and regularized Yoffe slip rate functions. We measured, together with shear stress, slip, and slip rate, the temperature evolution on the fault by employing an innovative two‐color fiber optic pyrometer. The comparison between modeled and measured temperature reveals that for calcite‐bearing faults the heat sink caused by decarbonation reaction controls the temperature evolution. In bare‐rocks, energy is dissipated as frictional heat, and temperature increase is buffered by the heat sink of the calcite decarbonation reaction. In gouges, energy is dissipated as frictional heat and for plastic deformation processes, balanced by the heat sink caused by the decarbonation reaction enhanced by the mechanochemical effect. Our results suggest that in calcite‐bearing rocks, a common fault zone material for earthquake sources in the continental crust at shallow depth, the type of fault materials (bare‐rocks vs. gouges) controls the energy dissipation during seismic slip. Plain Language Summary: During earthquakes, faults rocks lose strength, and therefore the ability to sustain shear stress as a consequence of slip, slip rate, and temperature resulting in dynamic weakening. The mathematical relationships between the decreasing strength and slip, slip rate, and temperature and the energy balance describing the partition of energy are of fundamental importance to model the propagation of an earthquake rupture. These relationships can be defined thanks to laboratory experiments that simulate seismic slip. Here, we tested calcite‐bearing fault rocks simulated as bare‐rock and gouges. During the experiments, temperature was monitored thanks to an innovative measuring system. Numerical models were done assuming all mechanical energy was converted into heat. By comparing all results above, we discovered that the mechanical energy in both bare‐rocks and gouges is converted to heat but limited by the occurrence of endothermic decarbonation reaction. In gouges, also an energy contribution for plastic deformation processes is required. Our work implies significant changes in the commonly accepted energy budget for earthquake propagation and show the importance of slip rate and temperature in driving together the dynamic weakening during seismic slip. Key Points: We measure temperature, shear stress, and slip rate to assess energy dissipation during seismic slip in calcite‐bearing fault materialsCalcite decarbonation compensates frictional heat production in all tested fault materialsMechanical energy is dissipated for frictional heat in bare‐rocks and for frictional heat and plastic deformation processes in gouges [ABSTRACT FROM AUTHOR]

A systematic revision of Alethopteris and Neuralethopteris from upper Namurian and lower Westphalian (Middle Pennsylvanian) strata of Nova Scotia and New Brunswick, eastern Canada, has demonstrated the presence of eight species: Alethopteris bertrandii, Alethopteris decurrens, Alethopteris cf. havlenae, Alethopteris urophylla, Alethopteris cf. valida, Neuralethopteris pocahontas, Neuralethopteris schlehanii and Neuralethopteris smithsii. Restudy of the Canadian material has led to new illustrations, observations and refined descriptions of these species. Detailed synonymies focus on records from Canada and the United States. As with other groups reviewed in earlier articles in this series, it is clear that insufficient attention has been paid to material reposited in Canadian institutions in the European literature. The present study emphasizes the similarity of the North American flora with that of western Europe, especially through the synonymies. Une revision systematique des Alethopteris et Neuralethopteris des strates du Namurien superieur et du Westphalien inferieur (Pennsylvanien moyen) de la Nouvelle-Ecosse et du Nouveau-Brunswick, dans l'est du Canada, a demontre la presence de huit especes : Alethopteris bertrandii, Alethopteris decurrens, Alethopteris cf. havlenae, Alethopteris urophylla, Alethopteris cf. valida, Neuralethopteris pocahontas, Neuralethopteris schlehanii et Neuralethopteris smithsii. L'etude du materiel canadien a mene a de nouvelles illustrations, observations et descriptions raffinees de ces especes. Les listes detaillees de synonymes se concentrent sur les documents du Canada et des etats-Unis. Comme pour les autres groupes examines dans les articles precedents de cette serie, il est clair qu'une attention insuffisante a ete accordee aux documents deposes dans les institutions canadiennes dans la litterature europeenne. La presente etude souligne la similitude de la flore nord-americaine avec celle de l'Europe occidentale, notamment a travers les synonymies. [Traduit par la redaction], INTRODUCTION This study is the ninth part of a revision of upper Namurian and lower Westphalian flora of Nova Scotia and New Brunswick, Maritime Provinces, Canada, begun in 2000 by [...]

This paper presents a taxonomic revision of filicopsid taxa from the lower to middle Westphalian strata of Nova Scotia and New Brunswick, Maritime Provinces of Canada. Most of the material represents sporadic historical collecting by Geological Survey of Canada (GSC) personnel, and specimens are in the GSC collections in Ottawa. Additional specimens are in the New Brunswick Museum at Saint John, the Fundy Geological Museum at Parrsboro, and the Joggins Fossil Institute at Joggins. Two specimens from outside Canada clarify specific characteristics. The revision involved the detailed examination of 20 adpression (mainly impression) taxa, of which one, Germera brousmkheae, is new. Detailed synonymy lists, with particular focus on records from Canada and the USA, facilitate a refinement of the stratigraphic and geographic distribution of these species. Most of the taxa from the Maritimes are the same as those from other parts of the paleoequatorial belt of Pennsylvanian times. The Maritimes record of filicopsid taxa closely resembles the filicopsid floras of western Europe, most notably the British Isles. Cet article presente une revision taxonomique des taxons de Filicopsida provenant de la strate westphalienne moyenne a inferieure de la Nouvelle-Ecosse et du Nouveau-Brunswick, des provinces maritimes du Canada. La plupart des documents decrivent la collecte de donnees historiques sporadiques effectuee par les membres du personnel de la Commission geologique du Canada (CGC), et des specimens se trouvent dans les collections de la CGC a Ottawa. D'autres specimens sont exposes au Musee du Nouveau-Brunswick de Saint John, au Fundy Geological Museum de Parrsboro, et au Joggins Fossil Institute de Joggins. Deux specimens preleves a l'exterieur du Canada apportent des precisions sur des caracteristiques particulieres. La revision a necessite l'examen de 20 taxons en adpression (principalement en impression), parmi lesquels un taxon, Germera brousmkheae, est nouveau. Des listes detaillees de synonymes, mettant un accent particulier sur les registres provenant du Canada et des Etats-Unis, facilitent le raffinement de la repartition geographique et stratigraphique de ces especes. La plupart des taxons des Maritimes sont les memes que ceux des autres parties de la ceinture paleoequatoriale du Pennsylvanien. Les registres de taxons de Filicopsida provenant des Maritimes ressemblent fortement aux flores de la classe des Filicopsida de l'Europe de l'Ouest, plus particulierement des iles Britanniques. [Traduit par la redaction], INTRODUCTION This study is the eighth part of a taxonomic revision of the upper Namurian to middle Westphalian floras of the Maritime Provinces of Canada. The revision was embarked upon [...]

As part of a larger project to revise the systematics of lower Westphalian floras of Nova Scotia and New Brunswick, the sphenopsid taxa are presently reviewed. We recognize 15 species, of which one, Annularia stopesiae, is new. Detailed synonymy lists allow a refinement of the stratigraphic and geographic ranges of these species. Scant attention has been paid previously to Canadian species in the European literature. For example, Annularia latifolia was described later from Europe as Annularia jongmansii. The identical composition of Westphalian floras from Canada and western Europe is striking. La revision de la flore du Westphalien inferieur de Nouvelle Ecosse et Nouveau Brunswick a ete continue a present avec les sphenopsides. Nous avons reconnu quinze especes, y compris une nouvelle, Annularia stopesiae. L'analyse des synonymies a permis etablir l'extension stratigraphique ainsi que la repartition geographique de cettes especes. On constate que les auteurs europeens ignoraient souvent les especes decrites au Canada. Un example a citer est Annularia latifolia qui est la meme espece qu'Annularia jongmansii decrite en Europe. On constate ausssi, une fois de plus, que la flore westphalienne est identique pour l'Europe occidentale et Canada. [Traduitpar la redaction], INTRODUCTION While engaged in the taxonomic revision of upper Namurian to middle Westphalian floras of the Maritime Provinces of Canada, it became apparent that certain forms of the sphenopsid fossil-genera [...]