Geol 2312 Igneous and Metamorphic Petrology

GEOL 2312 IGNEOUS AND METAMORPHIC PETROLOGY

Lecture 1Introduction to Igneous Petrology and Earth’s Physical and Chemical Structure

Jan. 20, 2009

THE REALM OF IGNEOUS

AND METAMORPHI

C ROCKS

A Fundamental Dilemma to the Study of Igneous and Metamorphic Rocks and the Processes that Create

ThemACCESS

IGNEOUS PETROLOGY“Study of Rocks formed by the Crystallization of

Magma”

What do we want to know about magma?

What do we want to know about crystallization processes?

How do we study igneous rocks to address these questions?

COMPONENTS OF SCIENTIFIC “STUDY” OBSERVATIONS/INTERPRETATIONS

OF THE NATURAL WORLD

Melting Experiments Cr

ysta

llizat

ion

Expe

rimen

ts

COMPONENTS OF SCIENTIFIC “STUDY” OBSERVATIONS/INTERPRETATIONS OF

EXPERIMENTS SIMULATING THE NATURAL WORLD

COMPONENTS OF SCIENTIFIC “STUDY” OBSERVATIONS/INTERPRETATIONS OF

THEORETICAL MODELS THE OF NATURAL WORLD

Cobra MELTS InterfaceGhiorso & Sack (1995)

PHYSICAL AND CHEMICAL STRUCTURE OF EARTH

PRESSURE AND THERMAL GRADIENTS

From Winter (2001)

COMPOSITION OF THE EARTHHow Do We Know?

- Mantle Xenoliths

- Seismic Data

- Density Constraints

- Meteorites- stony ~mantle- iron ~core- chondrites ~whole earth

Plate Tectonics drives Two Stages of Crust-makingPlate Tectonics drives Two Stages of Crust-making1. Mantle partially melts to make ocean crust2. Ocean crust melts to make continental crust

1.1. Mid-ocean RidgesMid-ocean Ridges2.2. Intracontinental Intracontinental

Rifts Rifts3. 3. Island ArcsIsland Arcs4.4. Active ContinentalActive Continental

MarginsMargins

5.5. Back-arc BasinsBack-arc Basins6.6. Ocean Island Ocean Island

BasaltsBasalts7.7. Miscellaneous Intra-Miscellaneous Intra-

Continental ActivityContinental Activity kimberlites, carbonatites, kimberlites, carbonatites,

anorthosites...anorthosites...

TECTONO-MAGMATIC ENVIRONMENTS