Examples

Lake Vico, 1573 cm depth. Optical microscope view.

This laminated facies is alternating with an homogeneous facies. Measurements using image analysis are shown below.

Image analysis shows that the difference between sedimentary facies is only due to a different internal fabric of the elements of the sediment. The sedimentary input is similar for both facies.

Annual laminations at Nogaret are composed of 3 laminae:

diatom lamina (spring)
neoformed calcite due to saturation in the epilimnion (summer). This lamina shows usually a graded-bedding
mixing of diatoms, organic debris and clays (autumn and winter)

Detailed grain-size measurements could be performed on SEM views of the neoformed calcite lamina.

Nogaret, BSE picture at 376 cm depth. White grains is neoformed calcite.

Graded-bedding is not progressive. An interpretation is proposed below.

BUT

HYPOLIMNION WATER IS DENSER (NEAR 4°C)

FINEST ELEMENTS DON'T SETTLE IMMEDIATELY