Mitmetasandilised

Mitmetasandilised is a geological term describing rocks and sedimentary sequences that exhibit multiple, interwoven cycles of sedimentation and metamorphism across different scales and tectonic settings. The concept envisions repeated deposition of sand- and mud-sized particles, each subsequently altered by metamorphic processes, producing layered fabrics that persist through deformation.

The name blends elements implying multiplicity and transformation, and it is not widely standardized. It appears in a small set of theoretical discussions and is not an established taxonomic category in most geologic classifications.

Key features include alternating mineral assemblages and fabrics that are interleaved by metamorphic foliations, with grain-size or chemical zoning reflecting successive cycles. Isotopic systems may record age spectra corresponding to distinct metamorphic events superposed on underlying sedimentary sequences.

Occurrences are proposed for complex orogenic belts, accretionary prisms, and other settings with protracted sedimentation and metamorphism. Empirical examples are limited and debated, and the term remains primarily theoretical rather than widely adopted in field practice.

Reception is mixed. Proponents argue it helps account for intricate fabrics beyond conventional models; critics caution against over-interpretation and emphasize the need for explicit criteria and robust field evidence before broader adoption. Further research in field mapping, petrography, and isotope geochemistry is cited as essential to establish clear criteria and to distinguish mitmetasandilised signatures from other complex terrains.

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