Details

Autor(en) / Beteiligte

• Penniston-Dorland, Sarah C.
• Harvey, Kayleigh M.

Titel

Constraints on tectonic processes in subduction mélange: A review of insights from the Catalina Schist (CA, USA)

Ist Teil von

• Geosystems and geoenvironment, 2023-08, Vol.2 (3), p.100190, Article 100190

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2023

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •Catalina Schist mélange records evidence for subduction tectonic mixing.•Length-scales of mixing are 10s of km.•Peak ages of blocks are different by <10 Myrs, limiting timescales of mixing.•Subduction fluid flow and mixing changed chemistry and mineralogy of mélange rocks.•Mélange records connections to arc magma chemistry. Subduction mélange, with its distinctive block-in-matrix structure, is documented in exhumed fossil subduction zones worldwide. Rocks from these terranes preserve features that record tectonic processes from the time that the rocks were at the subduction interface. Careful study of these features allows for connections to be made with tectonic processes occurring in active subduction zones. The Catalina Schist mélange has served as an exhumed analog in such studies as it records abundant evidence for tectonic processes occurring at the subduction interface. Focusing of fluids in mélange matrix at the subduction interface is documented, and this fluid-rich environment may have contributed to seismic activity. Deformation and tectonic mixing juxtaposed disparate materials (mafic, ultramafic, and sedimentary rocks) over length-scales of 10s of km along the interface, occurring in concert with metasomatism and mass transport by fluids to create mineralogically, chemically, and rheologically distinct compositions. These processes may have impacted seismic behavior and plate geodynamics along with influencing the chemistry of arc magmas that form above the subduction interface. Evidence suggests that the duration of tectonic formation of mélange may be variable from one locality to another, with relatively small differences in peak ages of blocks of <10 Myrs recorded in the amphibolite facies rocks of the Catalina Schist. [Display omitted]