Extra Credit Option:Extra Credit Option:

Attend the Public Lecture by Prof. Antonio Lazcano on Tuesday (tomorrow) evening, Feb 11 at 7:30 PM in Gammage Auditorium here on campus. Write up a short summary 2-3 paragraphs for the talk, highlighting the aspects you found most interesting. Bring your write-up to class on Wednesday. Be sure to write your name and ASU ID at the top of the page.

Today’s Lecture:Today’s Lecture:

Plate margins and associated geological pheneomena.

- Intraplate hot-spots.- Divergent plate margins in continental

settings (origin of new ocean basins).- Convergent margins- Continental margin settings.- Transform margins (ridge transforms and

on-land transforms. Brief Review Quiz Next time: Interlude A and Chapter 5!

Location of Earth’s Hot-spotsLocation of Earth’s Hot-spotsPLATEPLATETECTONICSTECTONICS

Yellowstone Hot SpotYellowstone Hot SpotPLATEPLATETECTONICSTECTONICS

Yellowstone Hot SpotYellowstone Hot SpotPLATEPLATETECTONICSTECTONICS

Types of Plate BoundariesTypes of Plate BoundariesPLATEPLATETECTONICSTECTONICS

divergent boundaries

convergent boundaries

transform fault boundaries

3 types

Continental Rifting: East AfricaContinental Rifting: East Africa PLATEPLATETECTONICSTECTONICS

Red Sea (looking southeast)

PLATEPLATETECTONICSTECTONICS Opening of the Red Sea

Opening of the Red SeaOpening of the Red SeaPLATEPLATETECTONICSTECTONICS

Formation of Triple JunctionsFormation of Triple JunctionsPLATEPLATETECTONICSTECTONICS

ocean-continent

ocean-ocean

continent-continent

3 Types of Convergent Plate Margins

Types of Continental MarginsTypes of Continental Margins

“Active” Found along convergent

plate margins: Primarily around the Pacific rim. Characterized by active narrow continental shelves and active mountain building processes (earthquakes & volcanic activity). Accretionary wedges of sediment which are scraped off the top of a subducting slab.

Types of Continental MarginsTypes of Continental Margins

“Passive” Found within plate interiors:

Continental margin not = a plate marginExamples are continental margins around Atlantic. Broad continental shelves consist of thick wedges of sediment deposited along margins Few earthquakes or volcanic eruptions.

Comparison of Active and Passive Continental Margins

Transform fault boundaries

Strike-slip faults where plates slide past each other: No production/destructionof material

Most connect mid-ocean ridge segments

Others are “on-land” transforms like the San Andreas Fault.

Transform Plate MarginsTransform Plate MarginsPLATEPLATETECTONICSTECTONICS

Transform Plate MarginsTransform Plate MarginsPLATEPLATETECTONICSTECTONICS

On-Land Transform Faults

San Francisco Peninsula and San Andreas Fault

In-class exercise. Name:______________________GLG 101 Prof. Farmer ASU ID:________________

Compare the continental margin of the west coast of S. America with the east coast of N. America.

1) South Am.

2) North Am.

Questions:a) Active or passive continental margin?b) Draw a cross-section (a side view) of each area, labeling the most important features.