Rock Correlation
What is “Correlation”? Match rock layers of similar age from one outcrop to another outcrop Correlation is based on: Rock type Grain size Fossils Other distinctive features
A 1 B 2 C 3 4 D E 5
Objects that Aid in Rock Correlation Index Fossils Relatively short life span Found over a broad region (wide geographic distribution) Volcanic Ash Deposits
Which fossil is the index fossil? 3 widely scattered rock units (outcrops) Which fossil is the index fossil?
Example 1: In which landscape region of NYS could you possibly find fossils of the earliest insects? Answer: Erie Ontario Lowlands
Example 2: What NYS index fossil might you find on the Tug Hill Plateau? Answer: Graptolites, Nautiloids, Trilobites
Example 3: Which landscape region of NYS might contain fossils of dinosaurs? Answer: Atlantic Coastal Plain