tonian, cryogenian, and ediacaran periods. the most severe glaciation known in the geologic record occurred during the cryogenian, when ice sheets reached the equator and formed a possible "snowball earth." the earliest fossils of multicellular life are found in the ediacaran, including the earliest animals...
paving mixes achieve higher pg grades and incorporate perfectly into the asphalt blend with no need for high shear milling as is the case with many other modifiers. gilsonite can partially or totally replace, or complement, the use of sbs polymers in modified asphalts at a fraction of the cost. gilsonite-modified...