Embrittlement Within Viscous Shear Zones Across the Base of the Subduction Thrust Seismogenic Zone

نویسندگان

چکیده

Geophysical observations indicate that patches of localized fracturing occur within otherwise viscous regions subduction plate boundaries. These place uncertainty on the possible down-dip extent seismogenic zone, and as a result maximum magnitude thrust earthquakes. However, processes controlling where how occurs shear zones are unclear. We examined three exposures exhumed boundary Kyushu, Japan, which contain subducted sediments hydrated oceanic crust deformed at ?300 to ?500°C. preserve subduction-related deformation, in two studied has mutually overprinting relationship with quartz veins, indicating cyclical embrittlement. Where observed, fractures commonly near lithological contacts form viscosity contrasts. Mineral equilibrium calculations for metabasalt composition showing embrittlement pressure-temperature conditions dehydration reactions consume prehnite chlorite. In contrast, dominantly deformation occurred intervening conditions. infer close metamorphic reactions, only small stress perturbations required transient embrittlement, driven by reducing effective stress, and/or locally increased stresses along rheological Our results show protolith subducting lithosphere controls locations magnitudes metamorphosed crust. Therefore, compositional variations might drive substantial slip style.

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

heterogeneity within the orientalist discourse: representation of the orient in womens travelogues and mens paintings

from 1950s onward, new theories and critical approaches burgeoned across humanities. these theories were context-oriented; as a result, the analysis of discursive practices gained significance. thus, social, political, historical and cultural discourses that have been hitherto marginalized and considered inferior to literary texts, were introduced as important texts to be analyzed by critics. o...

Metamorphic evolution along the slab/ mantle interface within subduction zones

One view of the metamorphic subduction system supposes that coupled deformation and prograde/metasomatic reaction between the chemically enriched slab and the depleted mantle wedge promotes the formation of complexly hybridized lithologies along the slab/mantle interface. This type of model is based upon direct observations of the structure and petrology of high-P/T metamorphic complexes (e.g.,...

متن کامل

Aftershock Area Expansion and Mechanical Heterogeneity of Fault Zone within Subduction Zones

We investigate global variations in the pattern of aftershock area expansion associated with large subduction zone earthquakes. The expansion of aftershock areas with time is relatively small in the subduction zones of Alaska, the Aleutians, Mexico, and parts of the Kuriles and South America. These subduction zones are interpreted to be characterized by moderate to strong interplate coupling. I...

متن کامل

Subduction Zones

[1] Subduction zones are where sediments, oceanic crust, and mantle lithosphere return to and reequilibrate with Earth’s mantle. Subduction zones are interior expressions of Earth’s 55,000 km of convergent plate margins and are the geodynamic system that builds island arcs. Excess density of the mantle lithosphere in subduction zones provides most of the power needed to move the plates while in...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Geochemistry Geophysics Geosystems

سال: 2022

ISSN: ['1525-2027']

DOI: https://doi.org/10.1029/2021gc010208