1. Monster worm and sea star frenzy
December 2, 2009
Monster worm and sea star frenzy
Deep under the Antarctic ice, a rare, colourful burst of starfish and 3m-long monster worms has been filmed by a BBC camera crew. Filmed in time-lapse, the extraordinary swarm of deep-sea creatures gathers to feed in a frenzy on the body of a seal, which had sunk to the ocean floor. Such a bounty of food may only occur once every ten years in the ice-cold waters of McMurdo Sound, Antarctica. The images were taken by divers filming for the natural history series Life.
The time-lapse sequence revealed the feeding frenzy of hundreds of huge worms, starfish, brittle stars and sea-urchins.
Reading Ch. 14
Final Exam date: TU, Dec. 15
Material covered: Ch. 13, 14, 15, 16

2. Recap Eastern margin Southern margin Interior Western margin
Rifting, lava expulsion
EX: The Palisades (NY-NJ)
Southern margin
Depositional basin, evaporites
Gulf of Mexico
Interior
Erosion and deposition
Navajo Sandstone (Zion NP)
Western margin
Undergoing compression
Picking up exotic terranes

3. Sonoma Orogeny Island arc collision Forearc basin (Great Valley Grp)
Volcanic & ocean sediments
Accretionary prism (Fransciscan Cx)
blueschists
Foreland basin (Morrison Fmn)
Volcanic & terrestrial sediments
Picture of folded blueschists in CA

4. Cordilleran Orogeny 1st phase: Nevadan orogeny
Granitic magma intrusions
Ex: Sierra Nevadas
Ex: Idaho batholith

5. Cordilleran Orogeny 2nd phase: Sevier orogeny Low angle thrusts
Spring Mtns, NV
2nd phase: Sevier orogeny
Low angle thrusts
Sevier thrust belt

6. Cordilleran Orogeny 3rd phase: Laramide orogeny Why??
Uplift of basement rock and overlying sediments
Located further east
Why??
Very shallow angle thrust
No melting
Transfer of compressional forces
Sheep Mtn anticline, WY

7. Cordilleran Orogeny

8. Interior Craton Interior Seaway in late Cretaceous
Covered ~1/3 land area
Marine carbonate deposition
Niobrara Fmn
Oil, coal, gas origins
Niobrara Fmn, KS
Morrison Fmn
Morrison formation with white/pink Navajo sandstone in distance.

9. Life in the Mesozoic: Marine Seafloor
Paleozoic fauna gone
Bryozoans, crinoids, blastoids, tabulates, fusulinids
‘Marine revolution’
Bivalves, gastropods took over
Ex: Inoceramids
Crinoids replaced by spiny or burrowing echinoids
Reef builders
Scleractinid corals dominate early
Rudistids clams dominated later

10. Mesozoic Life: Water Column
Ammonoids
Changes in suture designs
Zig-zag to U-shaped to branched
Mesozoic index fossil
Belemnites
‘ancient’ squids
Planktonic life
Diatoms
Coccolithophores
Foraminiferans: globigerinids

11. Marine Vertebrates Bony fishes Reptiles Primitive sturgeons
Teleosts with mobile jaws, swim bladders
Ex: Xiphactinus
Reptiles
Plesiosaurs
Large reptiles
Ichthyosaurs
Completely aquatic (live births)
Mosasaurs

12. Marine Vertebrates Megalodon (shark) Great White relative