Search results
Results from the WOW.Com Content Network
The Moenkopi Formation is a geological formation that is spread across the U.S. states of New Mexico, northern Arizona, Nevada, southeastern California, eastern Utah and western Colorado. This unit is considered to be a group in Arizona.
Current ripples preserved in sandstone of the Moenkopi Formation, Capitol Reef National Park, Utah, United States. A bedform is a geological feature that develops at the interface of fluid and a moveable bed, the result of bed material being moved by fluid flow. Examples include ripples and dunes on the bed of a river.
Current ripple marks, unidirectional ripples, or asymmetrical ripple marks are asymmetrical in profile, with a gentle up-current slope and a steeper down-current slope. The down-current slope is the angle of repose, which depends on the shape of the sediment.
Part of a super-sequence of rock units called the Grand Staircase, the formations exposed in the Zion and Kolob area were deposited in several different environments that range from the warm shallow seas of the Kaibab and Moenkopi formations, streams and lakes of the Chinle, Moenave, and Kayenta formations to the large deserts of the Navajo and ...
The principles of lithostratigraphy were first established by the Danish naturalist, Nicolas Steno, in his 1669 Dissertationis prodromus. [1] A lithostratigraphic unit conforms to the law of superposition, which in its modern form states that in any succession of strata, not disturbed or overturned since deposition, younger rocks lies above older rocks. [2]
Reddish Moenkopi outcrop below volcanic rubble on Red Butte. Uplift marked the start of the Mesozoic and streams started to incise the newly dry land. Streams flowing through broad low valleys in Triassic time deposited sediment eroded from nearby uplands, creating the once 1,000-foot (300 m)-thick Moenkopi Formation. [57]
Specifically in sedimentology, a bed can be defined in one of two major ways. [2] First, Campbell [3] and Reineck and Singh [4] use the term bed to refer to a thickness-independent layer comprising a coherent layer of sedimentary rock, sediment, or pyroclastic material bounded above and below by surfaces known as bedding planes.
The formation rests on the "lower red member" of the Moenkopi Group and underlies the Shnabkaib Member of the Moenkopi Group. [4] More recently, the Virgin Formation is interpreted as a formation of the Thaynes Group. [6] The formation is interpreted as having been deposited in a near-shore shallow marine environment.