Sedimentary Structures

“Strata” on Mars (2004)

Stratafication

Bedding (1-300 cm)

Laminations (<1 cm)Massive Strata (>300 cm)

Inter-Bed Structures(within strata)

•Graded Beds•Cross Beds•Soft Sediment Deformation•Dropstones

Outcrop of turbidites, Carboniferous,

northwestern China.

Graded BedsDeath Valley, CA

Cross BedsZion National

Park, UT

Mars - Crossbeds

Soft Sediment Deformation

image credit: Roger Suthren. Bude Formation, Upper Carboniferous, N Cornwall

Dropstones

Norway

Intra-Bed Structures(on the

surface of strata)

•Ripple Marks•Mudcracks•Raindrop Impressions•Flute Marks

Ripple

Marks

Mudcracks

Glacier National Park, MT

Raindrop Impressi

ons

Flute Marks

Fossils

Unaltered Remains(Usually “younger”

fossils)

Amber

Mammoth Hair

2,400yr old Bog Man, Denmark

Subfossil Wood

“Fossilized” Remains

Permineralization

Replacement

Carbonization

Molds and Casts

Cast - Paleozoic Crinoid

Mold - Pennsylvanian Shark’s Jaw

“Trace Fossils”

Track: an impression made by a single foot. Trackway: a number of tracks made during a single trip. Trail: an impression made by a tail or other “non-foot”.

Burrows: a hole or holes an animal dug into loose sediment (like mud).

Eggs and Nests: shells that at one time would have contained babies and the nests that the babies would have been kept in.

Coprolites: poop that has become fossilized.

Trackways and Trails

Fish Fin Marks (Nova Scotia)

Trilobite Trails, New York505 million years old (Cambrian)

Dino Tracks (Connecticut)

Rodent Burrows

Worm Burrows

Middle Silurian, Grimsby Formation, Hamilton, Ontario

Dino Nests

Upper Cretaceous close to KT boundary,Henan province, China

Coprolites

Miocene Mammal (WA)

Cretaceous Hadrosaur (MT)