ESS102H1 Lecture : Lecture 3
Document Summary
Iridescent aragonite (a mineral) with trace elements (e. g. fe, mn, al, ba) that causes coloration. Trace fossils: preserved tracks, trails, burrows, borings; not the organism itself, bioturbation: process of disturbing sediment. S by organisms that walk past or burrowing in, or roots. Palaeoecology: the study of ancient organisms and their environments. S e. g. if coral fossils are found, it used to be a shallow water: assemblages. S groups of organisms that live together: fossil morphology. S the shape of their bodies: trace fossils. S shows what kind of organisms were there and how they moved. St. cuthbert rings: parts of an ancient sea lily (crinoid) that were broken up and fossilized. How do we use fossils in stratigraphy: to establish relative age of rock units, correlate units. What information do we need to do this: relative age of rock units, fossil species present in each unit, establish time of first and last appearance of each species geologic range.
