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).
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What does hummocky cross stratification indicate about 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).
How does 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.
What is hummocky terrain?
Hummocky terrain is composed of tracts of hillocks and depressions of variable size and shape, and occurs in areas that have been glaciated.
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.
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 is a hummocky moraine?
hummocky moraine A strongly undulating surface of ground moraine, with a relative relief of up to 100 m, and showing steep slopes and deep, enclosed depressions. It results from the downwasting (i.e. thinning) of ice which is usually stagnant.
What produces hummocky topography?
The most common explanation for the formation of hummocky topography, is that a thick cover of supraglacial moraine on top of a stagnant ice at the ice‐margin was let down as the ice melted (Johnson & Clayton, 2003, Boulton 1972).
What causes cross stratification?
As water or air flows into the lee side (downflow side) of an object it slows down, and some of the sediment that was in suspension will settle out. Cross stratification starts to occur when there are some imperfections already existing on the surface.
What causes hummocky?
An extremely irregular surface may be called hummocky. An ice hummock is a boss or rounded knoll of ice rising above the general level of an ice-field. 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.
How are hummocky moraines formed?
When a debris-covered snout melts over time material is gradually let down from the ice surface to produce an area of ‘hummocky moraine’.
How are outwash plains formed?
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.