igneous rocks

Overview of Earth Materials and Minerals

  • Introduction to Earth materials

    • Previous lecture covered mineral building blocks and formation

    • Upcoming lab focusing on mineral properties for identification

Laboratory Preparation

  • Lab orientation details

    • TA support: Avi will be present during lab sessions

    • Safety forms not required for mineral lab

  • Tools available for lab activities

    • Rock mineral kits provided

Chemical Composition of Minerals

  • Focus on silicate class minerals

  • Relationship between minerals and rock types

    • Formation of rocks from mineral combinations

    • Discussion on plate tectonics regarding rock formation settings

Rock Types

  • Three primary rock types:

    1. Igneous Rocks

      • Formed from crystallization of magma

      • Various textures indicate cooling history

    2. Sedimentary Rocks

      • Formed from accumulation of sediments over time

    3. Metamorphic Rocks

      • Pre-existing rocks altered through heat and pressure

  • Importance of the rock cycle in understanding rock formation

Igneous Rocks

  • Basics of igneous rock formation

    • Crystallization of magma as a key process

  • Types of igneous rock based on cooling location and rate

    • Intrusive rocks: Formed within the Earth, slow cooling

    • Extrusive rocks: Formed at the surface, rapid cooling

  • Textural categories

    • Phaneritic: Large, visible crystals

    • Porphyritic: Two crystal sizes; signifies varied cooling rates

    • Aphanitic: Fine-grained, crystals not visible

    • Glassy: Instant cooling without crystal formation (e.g., obsidian)

  • Composition affecting the type of igneous rock formed

    • Bowen's reaction series indicating mineral content in magma

Identifying Minerals in Lab

  • Overview of physical properties for mineral identification

    • Key properties include luster, color, streak, hardness, cleavage, fracture

    • Luster: Metallic vs. nonmetallic

    • Cleavage: Planes of weakness in crystal structure; may result in flat surfaces

  • Determining mineral properties

    • Cleavage versus fracture characteristics

    • Specific examples of minerals showcasing each property

  • Practical approach during the lab:

    • Hands-on experience using rock mineral kits

    • Emphasizing safety and collaborative learning

Resources and Assignments

  • Importance of gathering resources for future exercises

    • Open book and open resource format for upcoming rock and mineral exercises

    • Scheduled activities in labs designed to reinforce learning and identification skills

  • Encouragement to utilize lab experiences for effective study