CONODONT COLOR (CAI) VERSUS MICROCRYSTALLINE AND TEXTURAL CHANGES IN UPPER TRIASSIC CONODONTS FROM NORTHWEST GERMANY

Scanning Electron Microscopy on conodonts from the Middle Triassic ''T rochitenkalk'' from Northwest Germany with CAI values ranging from 1 t o 5 revealed structural alterations during progressive diagenesis. Con odonts with low CAI values of 1.5 already show syntaxial recrystalliza tion of apatite on the conodont surface. Aggrading crystallization of the internal structure occurs in conodonts with CAI=5. The usually sho rt-prismatic and blocky syntaxial crystallites become increasingly lon ger and an overall increase in crystallite size takes place. Conodonts from the telemagmatically heated sediments overlying the intrusive bo dy of the Vlotho Massiv are often corroded, i.e., they have pocked, fr osted to pitted surfaces with dolomite rhomb overgrowths, indicating c ontact with ascending dolomitizing brines.