However, it has developed an internal wide flood-tidal delta where around the flood ramp flood-oriented megaripple
fields (medium 3D dunes) are developed, as well as numerous superimposed linguoid, lunate and straight ripples (Table 2; Fig.
Rock thin sections were prepared from core samples drilled on both megaripple crests and troughs across the exposed rock face.
This study has described a unique sequence of megaripple sedimentary structures that occur within the Hampton Formation (Lower Cambrian) near the town of Erwin, Tennessee.
These megaripples are exposed on a single bedding plane that is exceptionally and unusually well preserved in three dimensions, thereby allowing for bed form measurement and analysis usually only possible for modern sedimentary deposits.
The morphological dynamics of intertidal megaripples
in the Mawddach Estuary, North Wales, and the implications for palaeoflow reconstructions.
Superimposed on the sand waves and sharing the same general crest orientation are megaripples
; these features have smaller wavelengths and heights and exhibit a complex three-dimensional pattern in plan view (Fig.
The sand does not appear as a continuous sheet but is formed into alternating patterns of light and dark tone indicating that the sand is formed as bedforms, mostly megaripples. The mussel reefs are found in areas dominated by sand as seen on the backscatter map (Fig.
The sand in the region of the reefs is not a continuous sheet and can be described as a zone of starved megaripples (Amos and King 1984).
By contrast, the sandstones which display many primary sedimentary structures (megaripples
, bars and sub aquatic dunes) accumulated in a non-confined hydraulic setting in a relatively shallow coastal environment (Fig.
Over this intertidal flat linguoid and straight crested megaripples
, sand waves and beach ridges migrate under high energy wave conditions.
In some outcrops cross-bedding can be related to megaripples
up to one metre high (Fig.