Leadville Limestone

Figure 1. Location and tectonic features of the late-Mississippian, northern Sawatch Range showing distribution of Leadville Limestone (After DeVoto, 1990).

The Lime Creek drainage is an alpine karst system developed in Mississippian Leadville Limestone on the west slope of the Sawatch Range, approximately 20 kilometers (12 miles) northeast of Aspen, Colorado (Fig. 1). The mapped area is approximately 23 km (9 mi ), at elevations between 2,740 and 3,350 m (9,000 to 11,000 ft). The area is bounded by tributary valleys of the Fryingpan River on the north, south, and and west. The eastern extent of the study area is defined by uplifted and exposed Precambrian granite, gneiss, and schist (Fig. 2). 

The Leadville Limestone is part of a carbonate shelf northwest of the Sawatch Uplift (Fig. 1). In Lime Creek, the Leadville is a massive to well-bedded, fossiliferous limestone... 

Figure 2. Geologic map of Lime Creek Study Area. Xm Precambrian migmatite, Cs Sawatch Quartzite, Cp Peerless Shale, Om Manitou Dolomite,Dp Parting Quartzite, Md Dyer Dolomite, Ml Leadville Limestone, Mu undifferentiated Mississippian, Pb Belden Shale, Qi Ivanhoe Till, Qb Biglow Till, Qt Thomasville Till, Qg undifferentiated till, Qbt Burnt Mtn. Talus, Qa alluvium White line indicates line of section shown in...

It appears that a karst surface formed soon after the Belden Shale was removed. After the Leadville was exposed, a main, lower branch to the cave, and a high-water overpass into the Formation Room were formed. The cave stream carried limestone and chert gravel and cobbles derived from surface exposures of the Leadville Limestone and from material eroded from the cave walls. 

Glacial ice may have been responsible for removing some of the rock that overlies the Leadville Limestone, exposing the limestone to karstification. As discussed previously, glacial ice also transported igneous and metamorphic material from exposed Precambrian bedrock westward, onto the limestone. Glacial effects on cave sedimentation and karst development vary throughout Lime Creek. 

Engel, A. E. J., Patterson, C. C. Isotopic composition of lead in Leadville limestone, hydrothermal dolomite, and associated ore. Geol. Soc. Amer. Bull. 68, 1723 (1957). 

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