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Kodachrome Basin State Park
Kodachrome Basin is a state park of Utah, USA. It is situated above sea level, south of Utah Route 12, and southeast of Bryce Canyon National Park. It is accessible from the north from Cannonville by a paved road and from the south by Road 400, a dirt road from the Page, Arizona area to Cannonville, passable for most vehicles in dry conditions. A longer but paved route to Tropic from the south is also available via US-89 and SR-12.
==Geology==
Differing geological explanations of the features in the park Kodachrome Basin State Park exist. One explanation is that the area was once similar to Yellowstone National Park with hot springs and geysers, which eventually filled up with sediment and solidified. Through time, the Entrada sandstone surrounding the solidified geysers eroded, leaving large sand pipes. Sixty-seven sand pipes ranging from two to 52 meters have been identified in the park.〔(Kodachrome Basin, Geology ) 〕
While others suggest these sandstone spires are the result of sandstone intrusions which were created as a result of the tectonic activity in the Plio-Pleistocene time, the time of the uplift of the surrounding plateaus. Indications for this model include the concentric vertical ring structure of the columns themselves where each of the three vertical rings of sandstone, central, inner, and outer, can be traced and matched to a distinct sedimentary formation below. Also the truncation of two of the structures, at Shepherd's Point, by Pleistocene sheet conglomerates, and other intrusions which pierce through Pleistocene river deposited conglomerates place the intrusion event in the Pleistocene. The river conglomerates are truncated by the sheet conglomerates. Sheet conglomerates are usually caused by major seismic activity. There are also quite large well-rounded clasts, ranging in size from 2.5 centimeters and greater, found along the outer layer of the sandstone spires which are from the Pleistocene river conglomerates. Smaller less rounded, more angular clasts, about a centimeter or less in width, are also found and are from the red claystones layers found in the intruded sandstones. These clearly indicate that the pierced formations were well lithified. Additionally, the area has large masses of sandstone dikes. The spires have no evidence of a chaotic, mixing flow regime, rather they indicate a laminar flow not suggestive of hot springs or geysers. The outer surface is highly lithified, but within a few millimeters, the sandstone is quite friable.〔
The primary argument against an intrusion event is the liquified state required for the seismic intrusions. The source sediments are Jurassic in age, therefore, it is argued, to have been lithified and unable to be liquified. But there are intrusive dikes which show liquification did occur. And the hardened red claystone layers, which are pierced, were fairly consolidated at time of the intrusion event, therefore, they required tremendous pressure in order to be pierced. Seismic pressure waves would provide such pressure. The fracturing of the claystones also suggest that the intrusive sandstones were point sources able to concentrate the fluid pressure to a small area of the overlaying rock. It is also noted that the intrusions cleanly sheared the claystones so that the concentric edge of the claystone abuts cleanly against the spires.〔Hornbacher, Dwight, ''Geology and Structure of Kodachrome Basin State Reserve and Vicinity, Kane and Garfield Counties, Utah,'' Master's thesis, Loma Linda University, 1985〕
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