Geology 1023 Earth History January to April 2016 Labs Tue & Wed

Geology 1023 David McMullin HSH Office hours: 11:30 – 1:00 Tu & Th (or appt.). Contact information

Geology 1023 Schedule –posted on ACORN Assistants –Tuesday: Baillie Holmes & Jon Shute –Wednesday: Jon Shute & Alex Squires

PowerPoints and Answer keys On lab website Link to website also on ACORN

Grading & Philosophy Grading –11 labs worth 25% –2 tests worth 15% GEOL 1023 more about getting to understand how information garnered in GEOL 1013 is used and integrated (i.e., grammar instead of vocabulary).

Materials Work in pencil Coloured pencils (for structure and correlations) Ruler Protractor Other (calculator, sometimes)

Questions?

Geology 1023 Lab # 1 Plate Tectonics

Plate tectonics Map of earthquake epicentres –vast majority of earthquakes occur in narrow zones, which commonly have a surface expression (fault) –clearly demonstrate the margins of major plates Use the map in textbook to do the exercise (p. 17, p. 16 in 6e) Purpose of the exercise is to familiarize you with the major plates and boundaries Plates and boundary exercise

Polar wander paths exercise 1.Draw the apparent polar wander path (APWP) for N. America using the information given –i.e., the pole for N. Am. at a given time is the distance given at the bottom of the page from the head of the arrow, and in the direction indicated by that arrow. 2.Trace N. America and its APWP 3.Overlay the traced N. Am. APWP on the Europe APWP. –Part will look the same = time during which N. Am. and Europe behaved as one (i.e., they were joined) –Part of the traces will be different = time during which N. Am. and Europe behaved differently (i.e., they became two separate continents)

Cambrian rocks deposited here (at tip of the arrow)

Paleomagnetic measurements indicate that the pole was 12,000 km away (in the direction of the arrow)

Therefore, measure 12,000 km (8 cm at the scale of the map) in that direction 8 cm C

Do the same with the other arrows and connect the resulting dots in a second zig-zag line. This line is the APWP for N. America. C

Polar wander paths exercise 1.Draw the apparent polar wander path (APWP) for N. America using the information given –i.e., the pole for N. Am. at a given time is the distance given at the bottom of the page from the head of the arrow, and in the direction indicated by that arrow. 2.Trace N. America and its APWP 3.Overlay the traced N. Am. APWP on the Europe APWP. –Part will look the same = time during which N. Am. and Europe behaved as one (i.e., they were joined) –Part of the traces will be different = time during which N. Am. and Europe behaved differently (i.e., they became two separate continents)

Plate divergence (spreading) exercise Figure 3 shows three stages in divergence of two continental fragments Questions are intuitive Q 3 (b) Note that the two positions marked C have reached their present position in 10 Ma. That is, distance C-C happened in 10 Ma. Pay attention to units and unit conversion (i.e., 100,000 cm per km and 1,000,000 years per Ma)

Magnetic profile caused by “stripes” of basalt of alternating polarity

Correspondence between magnetic profile (as measured across the ocean floor) and the magnetic time scale

Magnetic stripes exercise The “profiles” show the magnetization across the ridge Correlate changes from positive to negative Colour up according to your legend

Questions?