There is no time to write great posts these days because of my continued work on my diploma mapping report. Though I can share some stuff. Today I cut and polished a number of samples to enhance the illustration of my report. I didn't manage to polish them all but a few samples are done and I want to share two of the more spectacular ones.
First, I cut and polished a sample I already discussed here. Back then I thought it to be a carbonate tempestive with an erosive base. Right now I am not that sure. Either way the cement is entirely sparitic from the shells upward. Below one can also find micritic and sparitic cement. Very few ooids are cut and truncated by shells. So maybe it is still a storm layer or a very proximal debris flow of carbonate sand. You can find a wild mixture of grains from shells, snails, foraminifera even, ooids, coated grains, aggregate grains, etc.
Second is a cut sample of an oncoid bed that I also discussed earlier. These wonderful and easy to recognise oncoids show a great, irregular laminae, one as a gastropod as a nucleus and two of them are obviously bored with internal boring sediment. I am not so sure how to interpret the contacts between the oncoids. First I thought them to be slightly deformed by each other. Meaning they would have been still soft enough for that to happen. Some partial laminae seem to have broken off. But then some contacts look a little like pressure solution seams and the laminae are abrubtly truncated. The matrix is a carbonate mud with shells, snails and other stuff that I didn't bother to check out, yet.
(My excuses, I accidentally messed-up the scale. The scale in the oncoid image is suppossed to be 4 cm not 6 cm.)