PYRITE FRAMBOIDS AND THEIR DEVELOPMENT - A NEW CONCEPTUAL MECHANISM

It has been suggested that the two morphologies of sedimentary pyrite, framboids and euhedra, may reflect two distinct pathways of pyrite fo rmation. Framboids form indirectly via iron monosulphides, whereas euh edra form from direct precipitation from solution. A third pathway whi ch is bridging these two forms is proposed here, namely the continuous growth from a monosulphide globule through framboids to a euhedral si ngle crystal. It is also suggested that framboids probably occur over a range of three orders of magnitude, from the least complex microfram boids through framboids to polyframboids.