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The Pennsylvanian to Lower Permian, (end of the Paleozoic Era), Supai Group, is a slope-forming section of red bed deposits found at the southwest-to-south Colorado Plateau. Cliff-forming interbeds (sandstone) are noticeable throughout the group, as well as the largest cliff-former the topmest member Esplanade Sandstone. The Supai Group is especially exposed throughout the Grand Canyon in northwest Arizona, as well as local regions of southwest Utah (Virgin River valley region). It outcrops southeastwards in Arizona at Chino Point (south Aubrey Valley), Sycamore Canyon, and famously at Sedona as parts of Oak Creek Canyon. In the Sedona region, it is overlain by the Hermit Formation, and the colorful Schnebly Hill Formation. The Supai Group is coeval with the Hermosa Group of east and south Utah; the Hermosa Group extended southeastwards from Utah to Durango,〔Blakey, Ranney, 2008. ''Ancient Landscapes of the Colorado Plateau'', ''"Geologic X-sections"'', (cross-sections), p. XVIII. Type section, pg. 54.〕 extreme southwest Colorado, and adjacent to the Hermosa type section. ==Geology of the 4 member units== The oldest member (Early Pennsylvanian), the Watahomigi Formation is from sedimentary basins. It is composed of red mudstone, sandstone, and tan limestone.〔Blakey, Ranney, 2008. Chapter 4, (Pennsylvanian-Permian), pp. 29-55, p. 31.〕 As ocean levels rose, basins filled, and the Manachka Formation was laid down (especially in the Grand Canyon). Continentally aeolian sand became more widespread; the coeval Weber Sandstone was deposited in northeast Utah (Dinosaur National Monument region, northeast of the Uncompahgre Uplift).〔Blakey, Ranney, 2008. Chapter 4, (Pennsylvanian-Permian), p. 31.〕 From Middle to Late Pennsylvanian, the Ancestral Rocky Mountains, the northeast spur from Colorado, (the Uncompahgre Uplift) became the source region for further continental river and stream deposits. Rising sea levels and erosion led to the deposition of the Wescogame Formation, (Grand Canyon) by Late Pennsylvanian time, and in east Utah, (Paradox Basin, southwest of Uncompahgre Uplift, the Honaker Trail Formation); northeast of the Uncompahgre Uplift, the Weber Sandstone continued deposition. By Permian time, the Esplanade Sandstone (Supai Group member 4) was being laid down in northwest Arizona (Grand Canyon), and southwest Utah;〔(Esplanade Sandstone, geologic sequence, southwest Utah )〕 the coeval Cedar Mesa Sandstone was being deposited in east Utah. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Supai Group」の詳細全文を読む スポンサード リンク
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