Where can economic sand and gravel deposits be found?
Much of the sand and gravel used for construction purposes in Maine was deposited by water melted from glaciers. If possible, water runs downhill so most gravel deposits are found in valleys and other lowlands where they were laid down in glacial outwash streams, glacial lakes, or the ocean. Ice-tunnel deposits (eskers) are notable exceptions. Some of these ridges of sand and gravel, deposited in confined subglacial tunnels, climb up hillsides and pass through elevated gaps in the hills. Surficial geologic maps are a useful guide to where geologists have found sand and gravel resources on land. Sand and gravel deposits are also present on the coast, in Maine’s beach and dune systems, and offshore on the sea floor. Due to significant environmental restrictions or logistical constraints these are not economically available resources.
