Geo Quiz 2 - Earths Earliest Atmosphere Dissolved iron in...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Earth’s Earliest Atmosphere Dissolved iron in the seas combined with oxygen When iron got all used up, O cont.’d to enter the atmosphere, oxidizing it… making animals possible Animals must breathe air or dissolved O in the water First you make O, then you soak it up, then you accumulate it in the atmosphere Along came the 1 st animals Ediacara (latest Precambrian) Soft bodied Not fossilized well Passive (waited for food to walk to them) Burgess shale fossils (middle Cambrian) Much more diversified Passive/active, soft-/hardparts, etc… Reading the strata Primary, secondary, tertiary, etc… inadequate classification of strata “tertiary” and “quaternary” survived Laws and principles (situations fulfilled most of the time) Law of superposition In an undisturbed sequence, younger lies on top of older Principle of original horizontally When deposited, strata normally deposit horizontally If you see something dipping, in most circumstances it was deposited horizontally, but something caused it to dip (there will be a question on this) Law of crosscutting relationships Younger cuts older Ex. Fault, dike (igneous intrusion), surface of erosion cutting across Principle of Lateral Continuity Even if a strata is not continuous all the way through
Background image of page 1

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

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 4

Geo Quiz 2 - Earths Earliest Atmosphere Dissolved iron in...

This preview shows document pages 1 - 2. Sign up to view the full document.

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