Lecture_16_Snowball_Earth

Lecture_16_Snowball_Earth - 1 2 Neoproterozoic Ice Ages...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
1 1 2 Neoproterozoic Ice Ages (600 mya) Low Latitude glaciation at sea level Banded Iron Formations- first appearance since rise of O 2 in atmosphere 2 bya Carbonate rocks (usually warm water today) above glacial deposits Very low 13 C/ 12 C in these carbonate rocks
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 3 striations tills dropstones 4
Background image of page 2
3 5 Evidence for glaciation: striations 6 Evidence for glaciation: tills
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 7 Evidence for glaciation: tills 8 Neoproterozoic striations and tills
Background image of page 4
5 9 Glaciation at Sea Level Today: Greenland Photo by Gary Comer 10 Glaciation at sea level: today
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 11 Neoproterozoic glaciation at sea level 12 Evidence for Glaciation • Grooved and polished surfaces • Unsorted (boulders, rocks, sand, clay) sediments (“till”) • Dropstones (ice rafted) in marine sediments* *Evidence for glaciation at sea-level
Background image of page 6
7 13 Today (and in all recent ice ages) glaciation at sea-level occurs only in high latitudes 14 • Sediments accumulate in horizontal layers • Magnetic minerals orient themselves parallel to field lines • If sedimentary rock forms in low latitudes magnetic minerals are aligned parallel to
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 18

Lecture_16_Snowball_Earth - 1 2 Neoproterozoic Ice Ages...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online