Online guide to the continental Cretaceous-Tertiary boundary in the Raton basin, Colorado and New Mexico

Sites to See

Raton to Sugarite, New Mexico

This segment of the trip involves a hike along a good trail through some rugged terrain. To reach Sugarite (Fig. 1) go north on I-25 and turn east from Raton via New Mexico highway 72. The route crosses outcrops in creek bottoms of the upper (Exiteloceras jenneyi) part (Campanian) of the Pierre Shale (Pillmore and Scott, 1994) and gravelly alluvium on the broad flats formed by the Barilla and Beshoar pediment surfaces (Scott and Pillmore, 1993; Pillmore and Scott, 1976). Along the route, to the north, large landslides cover much of the slopes below the 3.5 Ma basalt caps of Bartlett Mesa. To the east, landslides also cover the slopes beneath the 7.2 Ma basalt cap of Johnson Mesa (Stormer, 1972). As a side observation, about a mile from the Interstate, the view to your left reveals a broad valley containing a small hill that contains a diatreme (breccia-filled volcanic pipe formed by a gaseous explosion). A fission-track date by C. Naeser of the USGS on zircon grains in a quartzitic sandstone (Trinidad Sandstone or possibly Dakota Sandstone) block yielded 25 ± 1.4 Ma, younger than the sedimentary rocks in the area but older than the oldest basalt. This number dates the last time the rock was heated past the annealing temperature of zircon, 200 ± 25°C.

About 3.5 miles from the Interstate is the junction with New Mexico 526. Bear left and proceed left up Chicorica Canyon on New Mexico highway 526. On the left, cliffs formed by sandstone beds of the barren zone of the Raton Formation and the Trinidad Sandstone are visible in the upper slope. Basaltic lava flows cap Horse Mesa on the right and Bartlett Mesa on the left.

A short distance up the creek, large coal waste piles from the Sugarite mines become evident. Follow the trail through the abandoned Sugarite town site, and continue up the east side of the valley to examine an exposure of the Sugarite coal bed that contains the K-T boundary. The coal is about 6 ft thick and was mined for several years from entries on both sides of the canyon.

Sugarite

Sugarite is an abandoned mining town. Coal from the Sugarite bed was mined in this valley from about 1902 until the mines were closed in 1941. Coal was produced from Wagon Mine No. 2 until the main Sugarite mine (No. 1) was opened in 1912. The coal is high-resin, noncoking, and was prized for domestic fuel (Lee, 1917). The Sugarite coal camp was established in 1908 by the Chicorica Coal Co., and began full operation the following year

The opening of the Sugarite mine was hailed as one of the important developments in northern New Mexico, and the mine produced high-quality domestic coal for over thirty years. When the camp first opened it consisted of scattered tents, but within a short time the construction of a full fledged company town began. Managed by the St. Louis Rocky Mountain and Pacific Company, concrete and stone dwellings were built on slopes and terraces along the canyon sides, along with a mercantile store, schoolhouse, post office, and community center. The population of the camp fluctuated between 400 and 1,000 during its years of operation, and this mining community was considered one of the best coal camps in the area because of its beautiful setting along a running stream, its everyday amenities and community activities, and its first class equipment.

The Sugarite mines were located high on both sides of Chicorica Creek. Miners in the canyon relied on mules and burros to do the heavy work of pulling carts loaded with coal from the underground mines to the surface. From there, the coal was initially hauled by wagon to Raton, where it was used for steam generation and domestic purposes. A few years later, railroads served both the Sugarite and Yankee camps nearly every day, with coal runs to and from Raton and on to other markets.

Following closure of the mines, some of Sugarite's houses and buildings were moved to Raton, while others were simply torn down for salvage. Now all that remains of the camp are rows of rock foundations, the old post office, a mule barn, and a few residences and structures associated with the operation of the Lake Alice and Lake Maloya water systems. Further description of the mines and Sugarite Canyon State Park is given by Virginia McLemore (McLemore, 1990).

The area is mostly covered with landslide debris, soil, and vegetation. The Sugarite coal bed is exposed near the top of the lower coal zone of the Raton Formation in a landslide scar at about 7300 ft elevation on the east wall of the canyon about 450 ft above the valley floor. It has also been uncovered in a pit dug beside the trail. The Trinidad Sandstone forms ledges about mid-slope. The Sugarite coal bed is only about 90 ft above the top of the Trinidad and about 10 ft below the base of the cliff forming sandstones of the barren series.

The Sugarite coal accumulated in a large poorly drained backswamp on a broad, low gradient, alluvial plain near the eastern edge of the Raton basin. The thickness of the coal indicates a great accumulation of peat and a long period of stable conditions in the area. The presence of the isochronous K-T boundary clay allows us to correlate with confidence the coal zone observed at the Raton site with the Sugarite coal bed at Sugarite. The swamp or perhaps several smaller coeval swamps extended over an area of roughly 35 sq mi. The site differs from all other sites located to date in that beds of coal sandwich the K-T boundary claystone.

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Next: Stop 4 - The Sugarite K-T boundary site

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