A major environmental change happened in a since long lost time: the early Paleozoic.
Two colourful layers stand out in the limestone of the Ordovician Horns udde formation on the big island of Öland. These are called “the flowery leaf” and “the blood horizon”, named by local stone masons. It is not certain how these two layers formed, but it is clear that they represent a major environmental change affecting the entire marine ecosystem on Baltica during the Ordovician geological period.
Senast granskad: 2018-12-13