Garden of the Gods

This page features points of interest along the final pedal-to-the-metal leg of the Colorado geology road trip John Barr and I took in September, 2002. We left the Cathedral Lake trailhead in Castle Creek Canyon south of Aspen late in our next to last afternoon, bound for Garden of the Gods above Colorado Springs the next morning and Denver International Airport (DIA) by mid-afternoon to catch John's plane back to California.

Along the way, we encountered many attractions. We were in far too much of a hurry to do any of them justice, but we caught some interesting sights nevertheless.

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Independence Pass and the Sawatch Range
	Independence Pass: From Aspen, scenic CO82 took us first south and then east up the Roaring Fork River to Independence Pass (at 12,095', one of the highest in the US), where it crosses the crest of the towering Sawatch Range along a weakened fault zone. On average, the Sawatch is the tallest of the ranges comprising the Colorado Rockies. Looking south from CO82 at the ghost town of Lincoln Gulch just west of the pass, these visible and NIR photos show a large glacial cirque carved into Independence Mountain (12,703'), part of a ringed Tertiary intrusive and volcanic complex that may be a large dissected volcano. East of the pass, CO82 descends with the North Fork of Lake Creek along the southern flank of Mt. Elbert (14,433'), the highest peak in Colorado.

	Mount Massive: In the 1st frame, aptly named Mt. Massive (14,421', 2nd highest peak in Colorado) looms to the west from the Leadville airport, the highest in North America at 9,927'. Some of the aerial photos on this site came from the back seat of this 300 hp Cessna 182 while my pilot friend Jim Fischer (left, 1st frame) practiced his mountain flying with instructor ^Ron Zawadzinski on his right in the 2nd frame. Leadville attracts mountain flying trainees and flight tests from all over the world. Jim was proud to collect one of the "I landed at Leadville" certificates the airport operator issues.) you get a much closer look at Mt. Massive just east of Independence Pass, which is just out of view to the left in the 3rd frame. The helicopter in the 1st frame was a new Huey adaptation under testing by the US Forest Service.


Twin Lakes and Lake Creek Valley
	Twin Lakes: After an overnight at the Nordic Inn in Twin Lakes, we set out early to take in Florissant Fossil Beds National Monument and Garden of the Gods before John's 5PM flight to Oakland. US24 first took us south and down via the spectacular upper Arkansas River valley, an active segment of the Rio Grande Rift. Hemmed in at first between high, sheer buff-colored 1.7 Ga Precambrian granite walls, the Arkansas valley broadened as we passed Mt. Oxford (14,153'), the northernmost Fourteener of the Collegiate Range, as the southern half of the Sawatch is known.
	Lake Creek Valley: The 1st and 2nd frames look SW from the town of Twin Lakes. Impressive Sawatch peaks frame the large classic U-shaped valley carved by the massive Pleistocene Lake Creek valley glacier. Just east of here, the glacier stuck its big nose into the Arkansas River valley, forcing the river east into the 1.7 Ga granites at the base of the Mosquito Range. The peak on the left is Twin Peaks (13,333'); the base of Parry Peak (12,683') is on the right. Hidden behind Twin Peaks is La Plata Peak (14,336'). The large Tertiary La Plata intrusion crosses the valley to form Parry Peak and perhaps Twin Peaks as well. The 3rd and 4th frames look to the east from the town of Twin Lakes down the broad outwash plain deposited by the receding Lake Creek valley glacier. Barely visible in the middle ground beyond the plain are Twin Lakes, originally dammed by the glacier's terminal moraine and now by man. The Mosquito Range, in the distance across the hidden Arkansas River, was the eastern limb of the Sawatch Range anticline before the Rio Grande Rift lopped it off in the Miocene. BTW, all the false-color ^near infrared (NIR) photos on this page were taken through a Hoya R72 NIR pass filter on an Olympus C-2020Z digital camera.



Southern Mosquito Range
	Trout Creek Pass: At majestic Mt. Princeton (14,197') in the Sawatch Range, we turned east to follow US24 up Trout Creek and across the south toe of the Mosquito Range via Trout Creek Pass (9,010' ??). Just west of the pass at US24 Milepost 223, this roadcut exposes Pennsylvanian sediments resting unconformably on 1.7 Ga Precambrian granite. The Pennsylvanian rocks (on the right in the 1st frame) are part of the faulted western limb of a large sedimentary syncline that floors South Park and ultimately includes Ordovician through late Cretaceous deposits. The Pennsylvanian limestone (white), sandstone (brown) and evaporites (gray) accumulated in the Maroon Basin between the Ancestral Rocky Mountain uplifts. A fault just east of here exposes even older Maroon Basin sediments.

Wilkerson Pass and South Park
	Wilkerson Pass panorama: After crossing South Park and the Elkhorn Thrust, eastbound CO24 took us back into the Front Range at Wilkerson Pass (9,705'). This south-to-north sweep looks back to the west across South Park toward the Mosquito and Sawatch Ranges. The 1st frame looks to the southwest from Wilkerson Pass over the Precambrian east wall of South Park, one of several large faulted Rocky Mountain synclines that somehow managed to escape Laramide and subsequent uplifts. The Mosquito Range forms the distant west wall of South Park. In the 2nd frame, West and East Buffalo Peaks (~13,471' and 13,411', respectively) dominate the southern Mosquito Range skyline at right center. Hard Tertiary andesitic volcanics that once filled a paleovalley now support their widely visible twin summits in a classic example of topographical inversion. Subsequent erosion of the paleovalley walls left the more resistant volcanics standing in positive relief. In the 3rd, 4th and 5th frames, the first low dark ridge on the floor of South Park beyond the foreground hill is a west-dipping hogback of lower Cretaceous Dakota sandstone recapitulating the sedimentary sequence found at the east-dipping Dakota Hogback between Denver and the Front Range. Upper Cretaceous Pierre Shale floors South Park on this side of the hogback. In the 6th and final frame, 1.7 Ga Precambrian metasediments bordering Wilkerson Pass on the north moved to the west up and over the Pierre Shale of the South Park floor along the Laramide Elkhorn Thrust, an analog of the Williams Fork Thrust bordering Middle Park to the north. The metasediments accumulated around one of the island arcs that accreted to the North American continent along the southern margin of the Wyoming Craton around 1.7 Ga.





Florissant Fossil Beds
Sorry, no pictures yet	Florissant Fossil Beds: We had no time for pictures on our whirlwind stop at ^Florissant Fossil Beds National Monument, but the story is worth recounting. By late Eocene time, a broad mountain valley floored by Pikes Peak granite and the Wall Mountain tuff had developed at Florissant. Tall redwoods flourished in the warm climate. But explosive volcanoes active to the west in the Sawatch Range and to the south in the Thirty-Nine Mile volcanic field soon changed all that. Around 34 Ma ago, a massive Early Phase lahar (volcanic mudflow) from the west paved over and dammed the valley to form ancient Lake Florissant. The 2x12 mile lake served as a sediment, ash and fossil trap for many years thereafter. Volcanic ash falling onto and washing into the lake provided the rapid burial by fine-grained sediments crucial to the preservation of delicate fossils. Periodic volcanic mudflow breccias covered the fine-grained lake deposits. Today, the Florissant beds give us a rare window into the mid Tertiary evolution of many plant and small animal species. They're unusually rich in insect fossils, with over 1,100 species cataloged to date.
Garden of the Gods Park
	First things first: Our first stop at Garden of the Gods was the gift shop, where John and I secured suitable offerings and sacrifices for our generous and understanding spouses in preparation for family life re-entry. This young lady guided us well—the goddesses were appeased.
	Garden of the Gods Park: The white, salmon and maroon towers and spires characteristic of the east side of Garden of the Gods are erosional remnants carved for the most part from strong, vertically-dipping Early Permian Lyons sandstone, here a coastal dune sand deposit durably cemented with silica and hematite derived from ferromagnesian minerals in the igneous and metamorphic rocks exposed by the Ancestral Rocky Mountain Orogeny. Elsewhere along the eastern margin of the Front Range, the neighboring and slightly older Permian-Pennsylvanian Fountain Formation is responsible for many spectacular flatirons, as at Red Rocks Park and ^Roxborough State Park near Denver, but the Fountain here is only weakly cemented and can muster only smaller edifices. These Lyons and Fountain strata lie at the southern tip of the largely Precambrian Rampart Range, an eastern splinter off the Front Range uplift. They've been preserved in part in a graben down-dropped between two major Laramide faults, the Rampart on the east and the Ute Pass on the west. The Rampart Fault splits the park. To its east are vertical Lyons strata and the spectacular spires and fins they create; to its west are gently-dipping strata and lower landforms like Balanced Rock in the final frame. The Three Graces march off to the SE in the 1st frame in this series. The 2nd and 3rd frames feature the Sentinels. A pair of dove-like birds watch the crowd from a small wind cave in the 4th frame, which details a Sentinel wall. The fenestration between the Kissing Camels atop North Gateway Rock is barely visible near the top of the 5th frame. The 6th frame features Balanced Rock, the most popular spot in the park by far. Its strata dip modestly to the east, as do most of the rocks west of the Rampart Fault. For more info and pictures, visit the worthwhile ^Garden of the Gods website.





	Garden climbers: We saw "climbing by permit only" signs at every turn in Garden of the Gods, but that didn't seem to be much of an obstacle. Climbers like the ones shown here were out in force on this warm, sunny mid-September day. They reminded John of his daughter Heather, an avid climber currently serving in the Peace Corps in Nicaragua. She'd love to climb here some day, he thought out loud. Vertical bedding planes are clearly visible on the face of the spire in the 2nd frame.

Pikes Peak from Garden of the Gods
	Glimpse of a giant: The 1.1 Ga Precambrian granite summit of Pikes Peak (14,110') dominates the southern skyline at Garden of the Gods, and for that matter, throughout the southern Front Range. Pikes Peak is merely the pinnacle of a much larger Pikes Peak Batholith extending 50 miles to the southeast beneath the High Plains. The high part of the batholith lost a cover of early Paleozoic sediments during the Ancestral Rockies Orogeny and later, a late Paleozoic through Mesozoic cover during the Laramide. The Pikes Peak Batholith formed during the Grenville Orogeny. Granites intruded at ~1.7 Ga and ~1.4 Ga are common in Colorado (in fact, the latter are common throughout North America and Europe), but intrusions of Grenville age are very rare here. All 3 photos here show Pikes Peak from Garden of the Gods. Gateway Rocks frame the broad summit in the distance in the 3rd photo in the late afternoon sun. For more views of Pikes Peak from Mount Evans, click here.

Gallery notes: The Independence Pass photos are from a trip to Aspen in July, 2002. The Leadville Airport photos and the mid-day photos at Garden of the Gods are from September, 2002. The late afternoon Garden of the Gods shots are from a return trip in October, 2002.

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References

In addition to the references cited on the home page and in supporting articles, this article relies on the following sources, in alphabetical order by first author:

Colorado Geology Photojournals

A Tribute to Colorado's Physical Past and Present

Right: Trees and snow mark major Laramide uplifts in green and white while salmon pink marks the Colorado Plateau in this true-color satellite image of Colorado and surrounding states, courtesy NASA, ^Visible Earth

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