Both the Bull Head Trail (5.9 miles long) and the Rainbow Falls Trail (6 miles long) begin from the Cherokee Orchard Road and end on Mount Le Conte. Both trails start on a large debris fan of predominantly boulders of metasandstone. The Bull Head trail crosses sheared rocks of the Elkmont Sandstone above the Greenbriar fault and both trails cross good exposures of the Thunderhead Sandstone that are well exposed at Rainbow Falls.

Looking at Mount Le Conte from the Gatlinburg Bypass, the large
debris fan underlies the valley in the center that extends from the
head of Cherokee Orchard Road to "Airport Road" in Gatlinburg.

Close up of Elkmont Sandstone

Rainbow Falls is where Le Conte Creek flows over gently-dipping
beds of Thunderhead Sandstone at 4326 feet above sea level on
the north face of Mount Le Conte. The metasandstone is
interbedded with dark gray to black metasiltstone that is exposed
along the trail above and below the falls. Angular blocks of
metasandstone of the Thunderhead Sandstone are colluvium
derived from the cliff by gravity and freeze-thaw processes.

Mount Le Conte

There is a lodge on top of Mount Le Conte, about 6360 feet above
sea level, for hikers with reservations.

Trillium Gap Trail and Grotto Falls

The Trillium Gap Trail (6.5 miles long) connects The Roaring Fork Motor Trail with Mount Le Conte. The trail begins on a large fan of debris of predominantly boulders of metasandstone and it crosses local colluvium and scattered outcrops of Elkmont Sandstone before it crosses Grotto Falls.Grotto Falls is where Surry Fork (a tributary of Roaring Fork) flows over nearly flat-lying ledges of metasandstone of the Thunderhead Sandstone at 3680 feet above sea level. The sandstone overlies dark gray to black slaty metasiltstone that is exposed along the trail at the approach to the falls. There is a natural overhang, or grotto, behind the falls where the Trillium Gap Trail crosses it.

Alum Cave Trail

The Alum Cave Trail (4.9 miles long) begins near the Newfound Gap Road and ends at Mount Le Conte. The trail crosses colluvium along Alum Cave Creek and Styx Branch where rocks of the Anakeesta Formation are exposed in Arch Rock. On the east side of Styx Branch at 4200 feet above sea level, Arch Rock is a large hole in black slaty rocks of the Anakeesta Formation where water and ice have eroded. The slaty rocks are highly fractured, folded, and have irregular pods and veins of white quartz in them.

The trail crosses a debris chute of a debris flow and deposits at several places on the route to Alum Cave. The spectacular scenery here is largely the result of debris flows that have stripped the vegetation and soil during high rainfall events to expose bedrock.

Alum Cave is a bluff of rocks of the Anakeesta Formation that forms a natural overhang along the Alum Cave Trail at about 5000 feet above sea level. The word Alum is a general term for hydrous alkali aluminum sulfate minerals that form as sulfide minerals weather. Alum Cave is recognized for the occurrence of "potash alum" (Palache and others, 1951). Local legend has the alum quarried here by Cherokee and Civil War for gunpowder.

Alum Cave is a bluff of rocks of the Anakeesta Formation that forms a natural overhang.

The rocks exposed here were named for the dark slaty rocks found on Anakeesta Ridge to the immediate southeast (King and others, 1958). The metasiltstone and phyllite exposed in the bluff is composed of quartz, muscovite, paragonite, chlorite, and accessory garnet, rutile, pyrite (fools gold), pyrrhotite, allanite, monazite, apatite, graphite, and zircon (Flohr and others, 1995). The musty sulfur-like smell and the yellow, white, and rusty-brown colors on the rock surface are from the weathering of sulfide minerals and secondary-minerals that weather from them. Fine-grained soluble secondary salt minerals form by the evaporation of acidic metal-bearing groundwater seeps. These minerals have been identified here: copiapite, alunogen, gypsum, halotrichite, pickeringite, melanterite, rozenite, slavikite, epsomite, and starkeyite (Flohr and others, 1995).

Also exposed within the metasiltstone are podiform bodies of light gray metasandstone and dark gray to black sandy dolomite. The bodies of sandstone and dolomite are interpreted to be local channel deposits that are now intrafolial isoclinal folds. These folds have near horizontal axial planes that parallel the dominant foliation. The origin of the dolomite-rich silt may be inorganic precipitate (Hadley and Goldsmith, 1963). Noteworthy is that similar silty dolomite occurs as lenticular clasts within granite boulder conglomerate of the Thunderhead Sandstone along Big Creek.

Aggregate of fine halotrichite needles and euhedral hexagonal
tabular grains of slavikite.

The bluff at Alum Cave is dark slaty rocks of the Anakeesta
Formation that contain pod-like bodies of metasandstone that are
tightly folded (1-meter stick for scale). Some of the rocks have a
dissolved, pitted surface that indicates dissolution of calcium
carbonate rocks. These are small bodies of sandy dolomite. White
powdery deposits on the bluff are secondary salt minerals that
precipitated from water seeps.

Chimney Tops Trail

The Chimney Tops Trail (2 miles long) begins near the Newfound Gap Road and ends at Chimney Tops.

Spectacular scenery is found in areas underlain by rocks of the Anakeesta Formation, and nowhere is this better seen than at Chimney Tops.

The Chimney Tops are two prominent knobs underlain by dark
slaty rocks of the Anakeesta Formation at about 4700 feet above
sea level.

The rugged landscape is characterized by narrow, steep-sided, serrate ridges with craggy pinnacles of bare rock with thin residual soils. Chimney Tops is underlain by rocks of the lower part of the Anakeesta Formation that are gradational above the massive to medium-bedded metasandstone of the Thunderhead Formation that are well exposed in the stream.

Boulders of Thunderhead Sandstone line the bed of Road Prong (second footbridge) at start of trail to Chimney Tops. crossing on the lower trail. The contact of the rocks of these two formations is crossed along the trail at about 3600 feet elevation above sea level. The black sulfide-bearing slaty shale and metasiltstone weathers to produce sulfuric acid with orange iron rust-stained on fresh exposures.

Dark slaty rocks of the Anakeesta Formation are exposed along the Chimney Tops Trail from about 3800 feet above sea level to the top. The rust color is due to weathering of sulfide minerals that give the rock a "peacock" or rainbow color close-up.

On Chimney Tops, tectonic folds of metasiltstone with axial planar cleavage are well-exposed.

Folds of dark slaty rocks of the Anakeesta Formation exposed at
the Chimney Tops have a pervasive cleavage that dips to the south.
The rocks are folded into anticlines and synclines but mostly they
dip very steep. The slab-like habit of outcrop and loose rocks of
the Anakeesta Formation are controlled by the pervasive cleavage.
Bedding is recognized as fine laminations on the plane of the cleavage. The trail along the ridge goes across the bedding. The ridge follows prominent joints that trend northerly

.
There are two Chimney Tops that are connected by a ridge developed along a prominent north-trending joint. The rocks have a pervasive cleavage that dips to the south.

From the promontory at about 4800 feet above sea level are views of Balsam Point (north) and Mount Le Conte (northeast). The contrasting landscape is a function of massive Thunderhead Sandstone that underlies Balsam Point and Anakeesta Formation that is exposed from Mount Le Conte and eastward.

The Boulevard Trail

The Boulevard Trail (5.3 miles long) connects the Appalachian Trail near the Jump off (approximately 2.7 miles east of Newfound Gap) with Mount Le Conte. The Boulevard Trail cuts across the strike of the stratigraphy and structure of the Anakeesta Formation and often follows a serated ridge that drops steeply on both sides.

Looking north at snow covered Mount Le Conte from the Boulevard
Trail.

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U.S. Department of the Interior \| U.S. Geological Survey URL: http://geology.er.usgs.gov/eespteam/smoky/ Page Contact Information: Scott Southworth ssouthwo @usgs.gov webmaster Boris Barrios bbarrios @ usgs.gov Page Last Modified: June 7, 2005