However , there is some debate on whether it was formed from an intrusion or a volcanic sediment pile .
In some areas , mainly in the northern area , the pillow basalts have been completely altered into a garbenschiefer - like amphibolite .
There is some debate on whether it was formed from an intrusion or a volcanic sediment pile .
In some areas , mainly in the northern area , the pillow basalts have been completely altered into a garbenschiefer - like amphibolite .