STATEMAP: How Federal-State Geologic Mapping Pays Off, From Alaska to Texas

Artwork by Kimber Petersen, from the USGS fact sheet.

What STATEMAP is

STATEMAP is part of the National Cooperative Geologic Mapping Program (NCGMP): a partnership of the U.S. Geological Survey (USGS), the Association of American State Geologists (AASG) and the state geological surveys.

• Why: Congress set up the NCGMP in 1992 because, though federal and state governments share an interest in geologic maps, no single group could meet the need for detailed ones.
• How: STATEMAP gives state surveys 1:1 matching funds for new mapping, using the expertise and reach of geologists across the country. By 2020 it had invested more than $150 million in 48 state surveys, matched dollar for dollar.
• What for: the states' own mapping priorities, plus work with neighboring states and the USGS on regional and national issues. Projects target important areas and address:
• • land-use planning;
  • mineral, energy and water resources;
  • earthquake, flood, sinkhole and landslide hazards;
  • urban and infrastructure development;
  • coastal resiliency;
  • groundwater quality.

Alaska: guiding mineral investment

Mining companies use geologic maps to judge an area's mineral resources and decide where to invest. The Alaska Division of Geological & Geophysical Surveys (DGGS) completed a STATEMAP-funded map of the Bonnifield volcanogenic massive sulfide (VMS) district, about 100 kilometers south of Fairbanks, along with geochemical data from its igneous rocks and ore. The district has two known VMS deposits and good potential for more zinc-silver-lead-gold-copper deposits.

• In 2016, White Rock Minerals, a multinational exploration company, began a project there.
• Using the DGGS map and data, it made key decisions on evaluating and acquiring property, choosing targets, staking more claims, and planning drilling.
• By early 2018, White Rock rated the two deposits as potentially world-class, had outlined 30 targets, and had grown its claims from 16 to 143 square kilometers — a substantial investment in Alaska's economy.

Idaho: healthier timberland

Geologic maps help show how geology shapes ecology. In northern Idaho, tree growth, mortality, fertilizer response and replanting success all depend partly on the bedrock and surface geology: nutrient-poor rocks mean poorer soils, nutrient-rich rocks richer ones.

• Forest managers at the Potlatch Corporation noticed that tree-health problems in their nearly 600,000 acres of forest followed the pattern of certain rock types.
• Using the Idaho Geological Survey's STATEMAP maps and reports, they found those rocks in the field and changed how they manage them — from adjusting fertilizer in some areas to planting other tree species in others. The survey's maps now underpin forest-health guidelines for commercial timberland.

Texas: a changing coast

Coastal environments never stand still. Geologic maps help track the erosion and deposition that can threaten safety and property. On the Texas Gulf Coast, maps by the Texas Bureau of Economic Geology (BEG), made through STATEMAP, give baseline data to judge how the coast is changing, whether people have caused it, and whether planned land-management decisions will help or harm. Gulf and bay shores face habitat loss from erosion, subsidence and sea-level rise, plus dredging, ship traffic, saltwater intrusion and ongoing development.

• A coastal atlas built from STATEMAP maps will guide management of Texas Parks and Wildlife's Powderhorn Ranch — 17,351 acres of unspoiled coastal prairie and the largest conservation investment in Texas history.
• BEG researchers are studying its ecosystems, including upland and wetland plants on the Ingleside barrier-strandplain, an ancient barrier system from the last Pleistocene interglacial. These wetlands shield communities from storm surges and sea-level rise, and support the local economy through recreation.

Iowa: water for the future

Rising demand for water — for farms, industry, biofuels and homes — led the Iowa Geological Survey to study how sustainable the state's surface and groundwater are. Building on the statewide bedrock map, it produced detailed maps that give a three-dimensional framework for identifying the layers that hold and move groundwater.

• STATEMAP mapping in north-central Iowa produced maps of shale distribution and thickness and structure contours, showing where water is stored and how aquifers are connected or separated.
• The Iowa Department of Natural Resources water-supply group uses them for water allocation and well-interference decisions.
• In Worth County, STATEMAP maps are helping plan irrigation wells, showing where to drill — at the surface and at depth — without interfering with existing wells.

More: the National Cooperative Geologic Mapping Program.

Sources

Based on U.S. Geological Survey STATEMAP Program—Geologic Mapping for the Public Good, USGS Fact Sheet 2019–3060 (July 2020), by Abby Ackerman and Darcy K. McPhee, U.S. Geological Survey; a work of the United States government in the public domain. The artwork is taken from the fact sheet's PDF; its photographs by a state geologist and a photographer credited by name only, and a state survey's map, are not reproduced.