Amherst College Geology
Sedimentary Structures

Wave Ripples
(oscillatory flow)

Current Ripples
(unidirectional flow)
Interference Ripples
(plan view; two different oscillatory flow regimes)

(oblique view; right side of photo)

(x-section view; note asymmetry of trough)
Herringbone X-stratification
(x-section view; above left of knife)
Adhesion marks
(plan view; wind-produced; note trace fossils at bottom of image)
Adhesion structures
(x-sectional view; note reticulate and irregular shape of x-laminations)
Raindrop Impressions
(plan view; superimposed on ripples)


Suspect-Microbial Structures

Sand Stromatolites
(plan view of microbial buildup; note cauliflower-like growth)
Sand Stromatolites
(plan view; widely spaced buildups)
Sand Stromatolites
(plan view of rippled surface)
Sand Chips
(note truncated end of bent laminated clasts; to lower left of coin)
Sand Roll-Ups
(to right of pen; note coiled laminated sand clast)

Inverted Flutes
(plan view; note bilobate trace fossil at top)

"Algal" balls
(plan view)
Old Elephant Skin
(plan view; note wrinkled texture)

Loaded Sand Laminae w/OES
(plan view; note laminae exfoliating on ripple crests)

Amherst College > Geology > Faculty > YT's page > Upper Cambrian Fossils & Structures > Sedimentary Structures