Table of Contents
What is Swaley cross stratification?
B: Swaley cross-stratification (SCS) was introduced by Leckie and Walker (1982, p. 143) to describe “a series of superimposed concave-upward shallow scours about 0.5–2 m wide and a few tens of centimeters deep” observed in fine to medium sandstone.
How do hummocky cross stratification form?
Hummocky cross-stratification is a type of sedimentary structure found in sandstones. It is a form of cross-bedding usually formed by the action of large storms, such as hurricanes. It takes the form of a series of “smile”-like shapes, crosscutting each other. They are not related to “hummocks” except in shape.
What is a Swaley?
views 1,428,169 updated. swaley cross-bedding A form of hummocky cross-bedding in which there are few or no hummocks, but swales are preserved.
What is trough cross-bedding?
Trough cross-beds have lower surfaces which are curved or scoop shaped and truncate the underlying beds. The foreset beds are also curved and merge tangentially with the lower surface. They are associated with sand dune migration.
What is hummocky topography?
‘Hummocky topography’ is a non‐genetic, descriptive term applied to landscapes with irregular hills and depressions. For example, some aeolian dunes and many karst landscapes are characterized as ‘hummocky’ (Johnson & Clayton, 2003).
What does hummocky cross stratification indicate about the depositional environment?
Ripple bedding, hummocky cross stratification, parallel (horizontal) to low-angle lamination and erosion structures (e.g., gutter and pot casts) indicate a deposition as proximal tempestites above the fair-weather wave base with frequent influence of storms (Knaust and Langbein, 1995).
What causes hummocky?
In geology, a hummock is a small knoll or mound above ground. Hummocky ice is caused by slow and unequal pressure in the main body of the packed ice, and by unequal structure and temperature at a later period.
What is hummocky sand and gravel?
They are composed of boulder gravel with a coarse sandy matrix of disaggregated granite, derived from the underlying bedrock.
What are the main types of cross-bedding?
The three types of cross-bedding under this classification are simple, planar, and trough. The lower bounding surfaces are surfaces of nondeposition, planar surfaces of erosion, and curved surfaces of erosion, respectively.
Where does trough cross-bedding form?
All Answers (6) Trough cross bedding isn’t restricted to sandstones. This sedimentary structure forms through the migration of dunes in subareal or subaqueous environments. There are some spectacular trough cross beds in some of the Mississipian limestone units in southern Indiana (USA).
What is a hummocky moraine?
Irregular mounds of glacial debris, commonly referred to as ‘hummocky moraine’, until recently were linked to ice stagnation during rapid climatic amelioration. This situation is particularly common where there is a transition from warm–based ice in the interior of a glacier to cold–based ice at the margins or snout.
What is an outwash plain made of?
Outwash plains and eskers form due to the flow of meltwater in front of (outwash plains) or beneath (eskers) that glacier ice. They are composed of glacial sediments that have been reworked by flowing water.