Authigenesisalter

Authigenesisalter is a neologism used in geology and sedimentology to describe the interaction between authigenesis and alteration within sedimentary rocks and diagenetic systems. Authigenesis refers to the in situ formation of minerals during burial and diagenesis, while alteration denotes later chemical modification of minerals and rocks by fluids, heat, or pressure. The term thus denotes processes in which mineral growth occurs in place and is subsequently modified or overprinted by later diagenetic or metamorphic conditions.

In practice, authigenesisalter describes sequences where early, in situ mineral formation sets up porosity, geochemical buffers, or mineral templates that are later changed by fluids. Examples include early pyrite formation followed by oxidation, clay mineral authigenesis followed by illitization or dissolution, and calcite cement that later recrystallizes or in part dissolves during diagenetic evolution. The concept emphasizes the temporal coupling of mineral creation and subsequent alteration rather than a single static assemblage.

Applications of this idea include interpreting reservoir quality and diagenetic histories in sandstones and carbonates, reconstructing paleoenvironments, and informing models of fluid-rock interaction in basins. Because authigenesisalter spans multiple stages of rock evolution, it highlights sequence and overprint effects rather than discrete mineral epochs.

Authigenesisalter is not widely standardized in textbooks or databases, and its usage varies across studies. Readers should consult the specific definitions in each work to understand how the term is being applied.