Remapping Florissant Fossil Beds: How GIS Interns Mapped All 6,272 Acres in 2022–2023

The ancient valley at Florissant Fossil Beds. NPS photo

Florissant Fossil Beds National Monument, in a basin of Colorado's Front Range, protects petrified redwood stumps and delicate impressions of ancient plants and insects. Its geology has been mapped since 1877; in 2022 and 2023, three interns redrew that map with modern equipment — covering the whole monument.

Saved from souvenir hunters

In the 1800s, early scientific surveys and pioneers explored Florissant's fossil-rich hills, and word of its wonders brought scientists and tourists alike. In the early 1900s, private tourist attractions and a Midland Railway station drew thousands of visitors — who helped themselves to chunks of petrified stumps and dug up the hills. After decades of advocacy, the monument was established on August 20, 1969.

Mapping Florissant, 1877 to 1992

Evanoff's map greatly improved the picture of where Florissant's rocks lie, but three decades of advances in location technology meant its units and contacts — the boundaries between rock units — needed checking and updating.

The internship

In 2022, the monument and Southern Utah University's Intergovernmental Internship Cooperative set up a series of GIS geologic mapping internships, both to improve the map for the care of its fossils and to give early-career scientists hands-on experience, networking and mentorship.

Interns with Dr. Meyer at the monument's entrance. From left: Ashley Martinovich, Paityn Schlosser, Ashlynn Little, Dale Ligon and Herbert Meyer. NPS photo

Their mentor was park paleontologist Dr. Herbert Meyer, who guided 71 other interns over 29 years before retiring in 2023 — he put off his retirement that spring to see the second season through.

Adeline Rich's geologic map of central Florissant Fossil Beds, October 2022. Image from the National Park Service's page

Five months in the backcountry

NPS Intermountain Region geologist Tim Connors joined Schlosser and Martinovich to introduce them to the rock units, visiting outcrops few visitors see.

Paityn Schlosser (left), with a tablet, and Ashley Martinovich (right), with a GPS receiver, before a group of petrified stumps. NPS photo

Most mornings the pair were among the first employees on site. They drove to a pull-off or trailhead and hiked in with a GNSS receiver and mobile GIS software:

• Schlosser, the geologic mapper, identified the layers and contacts and decided where each contact belonged on the map.
• Martinovich, the GIS specialist, tracked their position by satellite and attached the right metadata to each point.

They hiked dozens of miles a week, meeting wildlife, roaming livestock and the remains of homesteads, including in a 280-acre western parcel added to the monument in 2019 that had never been mapped. Changeable weather and technical trouble put a September finish in doubt, but in five months they mapped all 6,272 acres.

A possible new unit

In the monument's south, Meyer showed them dark andesitic mounds eroding from the hillside, strewn with overturned shale beds and pumice fragments — mapped by Evanoff in 1992 as the upper pumice conglomerate and upper shale beds. Should the hills get a new unit, or should the old descriptions stretch to fit? In June, Evanoff himself joined the discussion of what a new unit would mean for Florissant's geologic history. The andesitic flows, breccias and inclusions were mapped under a tentative name: the "andesitic diamictite."

The andesitic diamictite, in the monument's far south. NPS photo

The result

The final geologic map of Florissant Fossil Beds National Monument, 2023. NPS image

With support from the nonprofit Friends of the Florissant Fossil Beds, Schlosser and Martinovich presented a poster, "Unearthing Truths and Transforming Maps at Florissant Fossil Beds National Monument," at the Geological Society of America's 2023 conference in Pittsburgh.

The poster presented at GSA Connects 2023. NPS image

The authors credit the result to collaboration — Evanoff's foundation, Rich's first season, and the geologists before them.

Learn more

• Florissant Fossil Beds National Monument
• Florissant Fossil Beds Geodiversity Atlas
• The history of paleontology in the National Park Service

Sources

Based on Paityn Schlosser and Ashley Martinovich, "Fostering Paleontological Stewardship Through Geologic Mapping in Florissant Fossil Beds National Monument," Park Paleontology News, Spring 2024, National Park Service; a work of the United States government in the public domain; rewritten in hubnx's own words.