Plateteorien

Plateteorien is a proposed, but not widely accepted, category in meteoritics describing certain meteoritic fragments that exhibit flat, plate-like morphology. The term blends a root meaning flat with a suffix indicating a group of objects. In reported descriptions, plateteorien grains are tabular or lamellar, often thin, and may show layered or mosaic internal textures. They are typically found within brecciated meteorites or in melt pockets and can vary from micrometers to centimeters in size.

Reported characteristics include a predominantly silicate composition with occasional metallic inclusions, and a geometry that appears as planar sheets or plates within the host rock. Under microscopic examination, plateteorien textures are described as highly anisotropic, sometimes with visible cleavage or sheet-like zoning. The diagnostic features cited to distinguish plateteorien from other textures are not universally agreed upon, and criteria have varied between studies.

Proposed formation scenarios for plateteorien include formation by shock-driven planar cleavage during impact metamorphism on the parent body, or as exsolution and realimentation of minerals during cooling within differentiated crustal material. Another possibility is fragmentation of larger plate-like components during brecciation, preserving a planar geometry in the fragments. Because these narratives rely on limited samples and interpretation, they remain speculative.

Status and reception in the scientific community are cautious. Plateteorien is not part of the standard meteorite taxonomy, and its diagnostic criteria lack broad consensus. Critics argue that features labeled as plateteorien may reflect known textures such as lamellae or shock-induced sheets in other mineral contexts. Further study and replicated observations are needed to establish whether plateteorien represents a distinct and stable category.

See also: meteorite, shock metamorphism, breccia, lamellar textures.