1121 17022012

HANCURNYA  SESEORANG ADALAH DISAAT IA BERADA DALAM KOMANDO PEMIMPIN YANG BODOH DAN TIDAK PUNYA PENDIRIAN

Upheaval Dome: Diapiric Salt or Ground Zero?

Stucturally, it's a dome, but topographically, it's a crater. Simply stated, the entire structure appears as an eroded, 5.5 km (3.4 mi.) diameter crater surrounded by concentric rings composed largely of siltstone and sandstone. The central portion of the dome is a topographic depression eroded 350 m below the surrounding escarpment, which is ringed by a syncline and breached by a canyon cut through its west wall. The innermost portion of the crater has a central uplift or peak with a complex sequence of folded and faulted strata with an imbrication of thrust slices piled against the central peak and splayed towards the southeast.
Stratigraphically, Permian age White Rim and Cedar Mesa Sandstones of the Cutler Group lie at the center, the oldest exposed rocks of the dome. Upheaval’s rocks are progressively younger from its center to the rim. Like the layers of an onion, outwardly lie Triassic strata of the Moenkopi and Chinle Formations, Jurassic age Wingate Sandstone, Kayenta Formation and Navajo Sandstone. The outer rocks of Upheaval Dome dip outward, anticlinally, in all directions from the central peak. Non-resistant formations such as the Kayenta and the Chinle are eroded into strike valleys that encircle the center. Resistant sandstones stand tall as circular ridges, outermost of which is the Navajo. Upheaval Dome is located within the boundaries of the Paradox basin, and is therein underlain by the salt-bearing Pennsylvanian Paradox Formation.