posted by Bex .
I have to write a brief geological history of a region starting with the oldest events schist being the earlisest and then i have sandstone and gabbro, could you see if what i have wrote is correct
The schist would have probably originally been deposited first as a layer of mudstone, which through metamorphism formed into the layer of schist. An unknown layer of rock above the schist would have been present for the gabbro to then intrude into it (it could have formed by rapid cooling on the surface). Then through erosion/ weathering, the layers of rock above the schist would have eventually exposed the upper part of gabbro intrusion, finally more than one layer of sandstone would have been deposited and lithified (by being compacted and cemented) to form sandstone. I would assume the sandstone wasn’t present when the intrusion took place because it hasn’t gone through the phase of metamorphism