megaripple

megaripple

[′meg·ə‚rīp·əl]
(geology)
A large sand wave.
References in periodicals archive ?
The symmetrical profile and chemically mature nature of the megaripple sand requires a well-agitated setting, suggesting the influence of combined wave and tidal action.
This paper describes this unique megaripple sequence and explores possible modes of origin of these sedimentary structures in the shallow waters of the Cambrian Sauk Sea.
Bedding and megaripple orientation data were measured using a Brunton transit compass.
The exposed megaripple surface is dominated by medium- to coarse-grained quartz sandstone.
Rock thin sections were prepared from core samples drilled on both megaripple crests and troughs across the exposed rock face.
Slope angles for NE-facing megaripple faces range from [7-24.
Where opposing flow vectors are strongly assymetrical the megaripple profile also is strongly assymetrical and has a characteristic steep slip face of [30-35.
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.
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 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).
The megaripples in coarse sand associated with the mussel reefs are normally formed under flow conditions up to 60 cm [s.
2] Number Depth Total Geological Province of grabs (m) mussels Mean Range Sand with bioherms (SWB) 10 75-88 91 36 0-78 Gravel/cobble (G/C) 19 60-85 310 75 0-130 Gravel/scallop bed (G/SB) 5 79-86 69 28 2-52 Mottled gravel (MG) 3 74-84 184 123 98-160 Rippled sand 2 77-80 0 -- -- Sand with comet marks 6 70-75 0 -- -- Sand ribbons 3 75 1 -- -- Mottled sand 4 85-86 0 -- -- Continuos sand 0 -- -- -- -- Gravel with comet marks 3 63-65 2 -- -- Glacio-marine mud (GMM) 5 85-91 16 8 0-12 Gravel ripples 7 64-65 0 -- -- Mixed sand/gravel 2 48 0 -- -- Starved megaripples 0 -- -- -- -- Table 2.