Petrology Chapter 10Gautam Sen

Global Subduction

Dips of Subducting Plates

Slab behavior

Nature of Subduction Zone

Chilean & Mariana Type Subduction Zones

Arc rock classification: Andean Volcanoes

Adakites: A Special Type

Trace element characteristics

Trace elements: Fluid-friendly elements

Nd-Sr Isotope Composition

Pb Isotope Composition

IBM Arc

Evolution of IBM Arc

Andes: Spatial Zonation

Cross-section of C. Andean Arc

K2O – SiO2 in Andean Volcanoes

Magma Formation, Processing, Emplacement, and Eruption

Andes: Southern Volcanic Zone

K2O – Gravity relationship

Latitude vs. Sr-isotope ratio

C.R. Stern’s alternative explanation: Importance of subduction erosion

NSVZ – Northern section of Southern Volcanic ZoneSSVZ – Southern section of Southern Volcanic ZoneNSVZM – NSVZ MagmaSSVZM – SSVZ MagmaAFC – Assimilation-Fractional Crystallization

Cascades Volcanic Chain

Cascades Volcanism with Slab Migration

K2O-SiO2 Relationship

Leeman’s Diagrams

Melt Inclusions & the Daly Gap(Reubi & Blundy)

Grove’s Explanation of the Daly Gap: A natural consequence of basalt magma crystallization

Daly Gap: Bimodal Volcanism

Dehydration of Slabs

Hydrated “Wedge” Solidus

Calc-alkaline vs. Tholeiitic Trends: Grove’s summary diagram

Granitoids & granitoids (Frost Classes)

Granite Production Environments

a: Island arcb: Continental arcc: Contiental collisiond: Continental extension

Sierra Nevada, USA

Himalayan Batholiths

Toulumne Granite complex

Granite Production in Sierra Nevada Batholith (SNB)

P-T of Sierran Xenoliths (Ducea, Saleeby)

Deep Structure of SNB (Saleeby)

Isotopes of Xenoliths and SNB

Lithosphere delamination in SNB

Ash distribution from Bishop Tuff eruption

Long Valley Caldera

Long Valley Caldera (LVC) Products

LVC Products (Cont’d)

LVC Magma Chamber

Q-Ab-Or System

P= 1 atm P= PH2O = 0.5 GPa

Granitoids worldwide and the Granite “system”

Granitoid magma generation by melting