Welcome to the website for EEEC’s 2600-pound polished slab of stromatolitic jasper. The specimen comes from the Mary Ellen Mine of Biwabik, Minnesota. It is a sample of the sea floor during a significant early period of geologic history, before there were complex forms of life on the planet, and when oxygen was still building up in the atmosphere from the microbes’ photosynthetic processes.
Made possible by gifts from Mark and Kandi Sutich (Biwabik Mary Ellen Stone Company) and the Geology Associates.
Do you like to breathe? Thank the cyanobacteria, because the oxygen in our planet’s atmosphere was first generated by these microbes, beginning about 2.45 billion years ago. The concentric structures that you see in the polished rock are stromatolites, laminated structures that formed from the interaction of cyanobacteria and sediments. Approximately 1.878 billion years ago, on a shallow sea floor in what is now Minnesota, mats of photosynthetic cyanobacteria grew towards
the sun’s light, producing these stromatolites. The specimen is composed of jasper (red microcrystalline quartz) and magnetite (gray iron oxide).