Changes

==Terminology==

==Terminology==

To develop a working classification of shale tectonics, recognition that two primary classes of features occur is critical: (1) those associated with extrusion of fluids and material that does not involve grain-to-grain contact,<ref name=Battanietal_2010 /><ref name=Delisleetal_2010 /> and (2) those associated with larger scale deformation of apparent highly overpressured mud or shale substrates involving grain-to-grain plastic flow.<ref name=Elsleyandtieman_2010 /><ref name=Wieneretal_2010>Wiener, R. W., M. G. Mann, M. T. Angelich, and J. B. Molyneux, 2010, [http://archives.datapages.com/data/specpubs/memoir93/CHAPTER09/CHAPTER09.HTM Mobile shale in the Niger Delta: Characteristics, structure, and evolution], ''in'' L. Wood, ed., Shale tectonics: [http://store.aapg.org/detail.aspx?id=1023 AAPG Memoir 93], p. 145–160.</ref> In addition, several varieties of highly fractured seep features exist (Warren et al.<ref name=Warrenetal_2010 />). These features allow fluid leakage from overpressured beds, but they do not always involve plastic or fluid-mud extrusion. Shales form a variety of nonextrusive structures, many of which resemble features generated through mobile salt movement, such as domes, welds, and walls. In contrast, muds form a variety of extrusive features, such as volcanoes, ponds, and flows and can erupt explosively.

To develop a working classification of shale tectonics, recognition that two primary classes of features occur is critical: (1) those associated with extrusion of fluids and material that does not involve grain-to-grain contact,<ref name=Battanietal_2010 /><ref name=Delisleetal_2010 /> and (2) those associated with larger scale deformation of apparent highly overpressured mud or shale substrates involving grain-to-grain plastic flow.<ref name=Elsleyandtieman_2010 /><ref name=Wieneretal_2010>Wiener, R. W., M. G. Mann, M. T. Angelich, and J. B. Molyneux, 2010, [http://archives.datapages.com/data/specpubs/memoir93/CHAPTER09/CHAPTER09.HTM Mobile shale in the Niger Delta: Characteristics, structure, and evolution], ''in'' L. Wood, ed., Shale tectonics: [http://store.aapg.org/detail.aspx?id=1023 AAPG Memoir 93], p. 145–160.</ref> In addition, several varieties of highly fractured seep features exist.<ref name=Warrenetal_2010 /> These features allow fluid leakage from overpressured beds, but they do not always involve plastic or fluid-mud extrusion. Shales form a variety of nonextrusive structures, many of which resemble features generated through mobile salt movement, such as domes, welds, and walls. In contrast, muds form a variety of extrusive features, such as volcanoes, ponds, and flows and can erupt explosively.

Several terms are used to describe the processes and features of shale mobility. These include shale tectonics, mud diapirism, shale diapirism and diapirs, mobile shales, mud volcanoes, mud diatremes, mud flows, and finally, from the Greek, argillokinesis and pellitokinesis. Although many scientists continue to argue against the existence of mobile shale, the term is well entrenched in the lexicon and unlikely to go away. A [http://www.americangeosciences.org/georef/georef-information-services GeoRef] search on the topic of mobile shale resulted in 34 instances of the combined term present in the peer-reviewed literature. Mobile shale and mud are the primary subject of a 2003 publication from the Geological Society of London, Subsurface Sediment Mobilization (Van Rensbergen et al.<ref name=Vanrensbergenetal_2003>Van Rensbergen, O., R. R. Hillis, A. J. Maltman, and C. K. Morley, 2003, Subsurface sediment mobilization: Introduction, ''in'' P. Van Rensbergen, R. R. Hillis, A. J. Maltman, and C. K. Morley, eds., [http://sp.lyellcollection.org/content/216/1 Subsurface sediment mobilization]: Geological Society (London) Special Publication 216, p. 1–8.</ref>). This single publication accounts for 36 additional articles on the subject, quadrupling the previous literature offering.  

Several terms are used to describe the processes and features of shale mobility. These include shale tectonics, mud diapirism, shale diapirism and diapirs, mobile shales, mud volcanoes, mud diatremes, mud flows, and finally, from the Greek, argillokinesis and pellitokinesis. Although many scientists continue to argue against the existence of mobile shale, the term is well entrenched in the lexicon and unlikely to go away. A [http://www.americangeosciences.org/georef/georef-information-services GeoRef] search on the topic of mobile shale resulted in 34 instances of the combined term present in the peer-reviewed literature. Mobile shale and mud are the primary subject of a 2003 publication from the Geological Society of London, Subsurface Sediment Mobilization.<ref name=Vanrensbergenetal_2003>Van Rensbergen, O., R. R. Hillis, A. J. Maltman, and C. K. Morley, 2003, Subsurface sediment mobilization: Introduction, ''in'' P. Van Rensbergen, R. R. Hillis, A. J. Maltman, and C. K. Morley, eds., [http://sp.lyellcollection.org/content/216/1 Subsurface sediment mobilization]: Geological Society (London) Special Publication 216, p. 1–8.</ref> This single publication accounts for 36 additional articles on the subject, quadrupling the previous literature offering.  

Argillokinesis is a broadly applied, all-encompassing term used to describe the dynamics of uncompacted flexible clays. With broad consideration of previous literature, as well as numerous conversations with the scientific community of subsurface researchers, we propose herein to use the term shale tectonics to define the structuring within a basin associated with shale or mudstone plasticity or mobility, either as the cause of such mobility or as a result of such mobility. Mobile shales are defined as any manifestation of clay constituents (indurated or not) that show evidence of microscopic-scale fluid or plastic movement. We acknowledge that such mobility is currently poorly understood and may be some manifestation of microscopic shearing or as a reconstitution of partly indurated muds through diagenetic alteration.

Argillokinesis is a broadly applied, all-encompassing term used to describe the dynamics of uncompacted flexible clays. With broad consideration of previous literature, as well as numerous conversations with the scientific community of subsurface researchers, we propose herein to use the term shale tectonics to define the structuring within a basin associated with shale or mudstone plasticity or mobility, either as the cause of such mobility or as a result of such mobility. Mobile shales are defined as any manifestation of clay constituents (indurated or not) that show evidence of microscopic-scale fluid or plastic movement. We acknowledge that such mobility is currently poorly understood and may be some manifestation of microscopic shearing or as a reconstitution of partly indurated muds through diagenetic alteration.