Integrated estimates of the thickness of the fault damage zone in granitic terrain based on penetrative mesocracks and XRD analyses of quartz

Takahashi, Hideo; Takahashi, Kazuhiro; Shimada, Kōji; Tsutsui, Kosuke; Miura, Reiko; Kato, Narumi; Takizawa, Shigeru

doi:10.1016/j.jsg.2011.11.008

Cited by 13 publications

(11 citation statements)

References 26 publications

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“…1 and 2). Furthermore, several previous field studies and a borehole drilled into the MTL in the Iitaka region (referred to here as the ITA borehole) provide constraints on the tectonic history and deformation styles of the MTL in this area (e.g., Takagi 1985;Shimada et al 1998;Wibberley and Shimamoto 2003;Jefferies et al 2006a, b;Fukunari and Wallis 2007;Okudaira and Shigematsu 2012;Shigematsu et al 2012;Takagi et al 2012;Mori et al 2015). We focus on two areas where the MTL is well exposed, centred around the previously-described Tsukide outcrop (see Wibberley and Shimamoto 2003) in the west ( Fig.…”

Section: Introductionmentioning

confidence: 99%

The architecture of long-lived fault zones: insights from microstructure and quartz lattice-preferred orientations in mylonites of the Median Tectonic Line, SW Japan

Czertowicz

Takeshita

Arai

et al. 2019

Prog Earth Planet Sci

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We combine field mapping with quartz microstructure and lattice preferred orientations (LPO) to constrain the mechanisms and spatio-temporal distribution of deformation surrounding the Median Tectonic Line (MTL), SW Japan. In the study area, the MTL occurs either as a narrow gouge zone or as a sharp contact between hangingwall quartzofeldspathic mylonites to the north and footwall pelitic schists to the south. Along the northern margin of the MTL, there exists a broad zone of mylonitic rocks, overprinted by cataclastic deformation and a damage zone associated with brittle deformation. The mylonitic shear zone is dominated by coarse-grained protomylonite up to~100 m from the MTL, where fine-grained ultramylonite becomes dominant. We observe a systematic variation in quartz LPO with distance from the MTL. In protomylonites, quartz LPOs are dominantly Y-maxima patterns, recording dislocation creep by prism slip at~500°C. Closer to the MTL, we observe Rand Z-maxima, and single and crossed girdles, reflecting dislocation creep accommodated by mixed rhomb and basal slip, likely under cooler conditions (~300°C-400°C). Some ultramylonite samples yield weak to random LPOs, interpreted to result from the influx of fluid into the shear zone, which promoted deformation by grainsize-sensitive creep. Following cooling and uplift, deformation became brittle, resulting in the development of a narrow cataclasite zone. The cataclasite was weakened through the development of a phyllosilicate foliation. However, healing of fractures strengthened the cataclasites, resulting in the development of anastomosing cataclasite bands within the protomylonite.

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Section: Introductionmentioning

confidence: 99%

The architecture of long-lived fault zones: insights from microstructure and quartz lattice-preferred orientations in mylonites of the Median Tectonic Line, SW Japan

Czertowicz

Takeshita

Arai

et al. 2019

Prog Earth Planet Sci

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“…The overall thickness of the fault damage zone is, however, much larger, extending to a distance of about 250 m on either side of the fault (Takagi et al . ). Dark green, fine‐grained diorite dikes intrude the Sugodani Granite, and both of these rock types together are highly fractured locally.…”

Section: Description Of the Magawa Outcrop And Pseudotachylyte Veinsmentioning

confidence: 97%

“…The Sugodani Granite exposed at the Magawa outcrop has clearly undergone intense cataclasis during Atotsugawa faulting, which has resulted in the formation of abundant cataclasite or fault breccia within about 10 m of the fault surface. The overall thickness of the fault damage zone is, however, much larger, extending to a distance of about 250 m on either side of the fault (Takagi et al 2012). Dark green, fine-grained diorite dikes intrude the Sugodani Granite, and both of these rock types together are highly fractured locally.…”

Section: Magawa Outcropmentioning

confidence: 99%

Geological framework and fission track dating of pseudotachylyte of the Atotsugawa Fault, Magawa area, central Japan

et al. 2013

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This paper describes newly discovered pseudotachylyte along the Atotsugawa Fault at the Magawa outcrop, where this fault divides Quaternary deposits in the SW from Triassic Hida granitic rocks to the NE. Within several meters of the fault surface, pseudotachylyte veins are found with a thickness of less than 10 cm, but are displaced by fault brecciation. Zircon fission track dating of pseudotachylyte samples yields ages of 48.6–50.2 Ma (sample AT‐A), 55.1 Ma (AT‐A'‐1) and 60.9 Ma (AT‐D‐1); the latter is similar to the fission track ages of 56.1–60.1 Ma for granitic protoliths. The results of fission track length analyses in zircon suggest that pseudotachylytes (AT‐A and AT‐D‐1) and protolith granite are mostly annealed. Consequently, the pseudotachylyte (AT‐A) reached the highest temperature during 48.6–50.2 Ma, thereby resetting the fission track system totally in zircon during faulting. Another pseudotachylyte (AT‐A'‐1) and its wall rock granite contain shortened tracks within zircon grains suggesting partial annealing. The age distribution pattern of the former also contains decomposed age after the normality test (Shapiro–Wilk test) in which the major age yields 52.5 Ma. Accordingly, these pseudotachylytes yield a peak age of about 50 Ma, whereas the peak ages of one pseudotachylyte (AT‐D‐1) and the protolith Hida granitic rocks are about 60 Ma, representing the thermal effects not caused by frictional heating but by intrusions of Late Cretaceous to Paleogene granitoids that are probably concealed below the exposed Triassic Hida granitic rocks. Such thermal effects did not affect the K–Ar muscovite age (149 Ma) for the protolith granite because of the higher closure temperature of this system. Using the new geochronological data, we can elucidate the cooling history of the Hida granitic rocks, and constrain the timing of the main pulse of pseudotachylyte generation along the Atotsugawa Fault at about 50 Ma.

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“…The dip of the MTL is 56˚N in western Mie Prefecture (Shigematsu et al, 2012) and approximately 62˚, where the MTL outcrops in the Taki area (Takagi et al, 2010) . Ductile to brittle shear zones within the fault core and within damage zones along the MTL have been investigated in western and central Mie Prefecture (Takagi, 1985;Shimada et al, 1998;Wibberley and Shimamoto, 2003;Jefferies et al, 2006;Takagi et al, 2010Takagi et al, , 2012Shigematsu et al, 2012) . However, the exact location of the surface trace of the MTL in eastern Mie Prefecture is poorly constrained and did not exhibited it as concealed fault in previous geological maps (e.g., Nishioka et al, 2010) , because of Miocene to Quaternary sediments cover and the devel- The confirmed location of the MTL in the famous Ise Grand Shrine (Geku) would be also of particular value for geo-tourism involving educational activities through creating a geosite (Kapuscik, 2014) .…”

Section: Introductionmentioning

confidence: 99%

Determination of the Exact Surface Trace of the Median Tectonic Line in the Ise Area, Southwest Japan

Suzuki

Takahashi

Kawamoto³

et al. 2015

Journal of Geography(Chigaku Zasshi)

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The Miocene collision of the Izu-Bonin arc with the Honshu arc in Japan is thought to have initiated eastward bending of the Median Tectonic Line （MTL） from an approximate E-W strike to an ENE-WSW strike in the Ise area of the easternmost Kii Peninsula. However, the exact surface trace of the MTL in the Ise area remains poorly defined because of Quaternary sediment cover and the development of urban areas. Determination of the surface trace of the MTL is important to evaluate the characteristics of seismic motion upon the paired metamorphic belts divided by the MTL, which reflects the subsurface geology, and to better explain the curvature of the MTL in central Japan. This paper presents the results of petrographic observations from several localities in the Ise area, including Tamaki Town and Ise City : boring cores at （1） the factory building of Miwa Lock Co., Ltd., in Tamaki Town, which overlie the MTL, （2） Ise City Hall, （3） Ise City Tourism and Culture Hall, as well as additional boring data from Ise City. The depth of pre-Neogene basement increases eastward from the Gokatsura area, ranging from 6-12 m in the Sanbagawa belt near Ise City Hall to greater than 30 m in the Ryoke Belt. A geological survey of rare exposures, including the Ryoke rocks of the Ooike pond area in Tamaki Town, Miocene conglomerate along the Miyagawa River in the Ryoke belt, and Sanbagawa schists in Ise City, have helped to constrain the exact location of the MTL in Ise City. Through this study we have also signalized the potential of investigated sites in Ise city to be used as prospect geosites in future. After proper development and promotion these sites can become important points of attention to be seen by visitors and geologists and provide various opportunities for local economy growth.

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Integrated estimates of the thickness of the fault damage zone in granitic terrain based on penetrative mesocracks and XRD analyses of quartz

Cited by 13 publications

References 26 publications

The architecture of long-lived fault zones: insights from microstructure and quartz lattice-preferred orientations in mylonites of the Median Tectonic Line, SW Japan

The architecture of long-lived fault zones: insights from microstructure and quartz lattice-preferred orientations in mylonites of the Median Tectonic Line, SW Japan

Geological framework and fission track dating of pseudotachylyte of the Atotsugawa Fault, Magawa area, central Japan

Determination of the Exact Surface Trace of the Median Tectonic Line in the Ise Area, Southwest Japan

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