Geologic Mapping in Wyoming
From the Stone Age to the Iron Age, local knowledge of geology and
geologic resources has been instrumental in the development of humankind.
Advances in technology have been directly related to understanding and
manipulating geologic resources. This geologic knowledge can be portrayed on a
geologic map.
A wind polished (ventifact) mafic intrusion in granite.
Geologic maps are detailed, complex tools that record a geologist’s observations
and analyses; they are fundamental for locating and evaluating mineral, energy
and water resources, and geologic hazards. The focus and expertise of individual
geologists differ, and these differences are portrayed in their mapping. Every
geologic map is unique to the age and needs of a culture and the civilization it
reflects.
The history of geologic mapping can be traced back to the ancient Egyptians. In
the early nineteenth century, archeologists discovered a 3,000-year-old papyrus
scroll in a tomb, a scroll that came to be called the Turin papyrus. Several
older topographic maps have been found, but these are crude in comparison with
the Turin papyrus (Harrell and Brown, 1992). The Turin papyrus map details the topology and geology of a
valley east of the Nile River. The author of the Turin papyrus mapped the
metamorphic rocks of the valley, which were then being quarried for sculptures
and monuments. He also mapped several actively-mined gold-bearing quartz veins,
as well as the geology of the surrounding hills (the river valley alluvium,
granites, volcanic rocks, and serpentinite). Three millennia would pass before a
geologic map of such complexity would again be created.
The history of geologic mapping in Wyoming begins with the storied expeditions
of two geologists, John Wesley Powell and Ferdinand V. Hayden. In May of 1869
(Powell, 1875),
Powell and a group of nine men departed in three small boats from Green River,
Wyoming to explore and record the Colorado River canyon lands. A year later, the
Hayden expedition began a quest to document the wonders of the Yellowstone area.
The goal of both expeditions was to evaluate the resources of the uncharted
Territories of the Western United States.
Their reports and maps were the first to describe the amazing geology of Wyoming
and the unlimited potential of its natural resources. The stories, photos,
sketches, and paintings in the reports of the Powell and Hayden surveys
captivated people worldwide, and helped create the mythos of the American West.
The tools geologists use for mapping have undergone considerable change since
the days of Hayden and Powell (and even more so since ancient Egyptians times).
A Brunton compass, topographic maps, a protractor, and a rock hammer will always
be indispensable to a field geologist, but nowadays field gear also consists of
GPS units, laptops, complex drafting programs, and various imagery obtained from
remote sensing. These tools help geologists at the Wyoming State Geological
Survey (WSGS) to make very detailed geologic maps. The WSGS’s geologic maps are produced,
stored, and accessed digitally, which allows for easy and instantaneous map
revisions.
Bedrock Geologic Map of the Lander Quadrangle.
(Click image to enlarge)
Like the explorers of centuries past, the geologists of the Wyoming State
Geological Survey (WSGS) Regional Geology and Mapping Group approach geologic
mapping with a sense of discovery and wonder. Many areas of Wyoming have yet to
be mapped at a scale of greater detail than 1:500,000 (1 inch represents 4
miles). The goal of the WSGS is to map the bedrock geology of the entire state
at a scale of 1:100,000 (1 inch represents 1.6 miles), and areas of interest at
a more detailed scale of 1:24,000 (where 1 inch on the map represents 2,000 feet
on the ground).
The Mapping Group’s current projects have three objectives: (1) producing
geologic maps to ensure and encourage responsible development of coalbed natural
gas (CBNG) and stewardship of associated ground and surface water in Wyoming;
(2) mapping the more populated areas of the state to assist cities and counties
in siting and land-use planning by providing geologic, hydrogeologic, and
mineral resource information to ensure and encourage responsible development;
and (3) mapping to characterize and assess mineral resources, to better
understand geologic and hydrogeologic systems, and to advance scientific
investigations and knowledge of Wyoming’s geology, thereby encouraging
responsible use and conservation of the state’s energy and mineral resources.
The goal of the WSGS is to create geologic maps that will help the residents of
Wyoming to responsibly use the resources of the state in a beneficial and
environmentally sound way.
Bedrock geology over color infrared photo.
Geologic maps serve the resource needs of communities, but also reflect the
goals and desires of the culture in which they are crafted. The Egyptians used
geologic maps to create monuments that would equal the works of their gods.
Early exploring geologists in Wyoming and the West created maps that helped fuel
a young nation’s dreams of adventure and wealth. The maps we create today help
advance and maintain our infrastructure and our material and energy needs.
The rugged beauty of Wyoming is the product of massive geologic forces over
hundreds of millions of years. It is our privilege as WSGS geologists to immerse
ourselves in investigating the forces that created such beauty.
References
Harrell, J.A. and V.M. Brown, 1992, "The world's oldest surviving
geological map - the 1150 BC Turin papyrus from Egypt", Journal of Geology 100
(1992), pp.3-18.
Powell, J. W. (1875). The Exploration of the Colorado River and Its Canyons. New
York: Dover Press.
Related Links
Please vist WSGS Geologic Mapping page for more information.