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