What This Document Is
This document is a laboratory guide focusing on extrusive igneous rocks – those formed from lava erupting onto the Earth’s surface, or very close to it. Specifically, it details the characteristics of basalts, diabases, andesites, and dacites, relating them to their intrusive equivalents (gabbro, diorite, and granodiorite respectively). It serves as a companion to coursework in petrology, the study of rocks.
Why This Document Matters
This guide is essential for students in GLY 4310C (Petrology Igneous Metamorphic Rock) at Florida Atlantic University. It’s used during lab sessions to aid in the identification and classification of these common volcanic rock types. Understanding these rocks is fundamental to interpreting Earth’s volcanic activity and the composition of the planet’s crust. Geologists, volcanologists, and anyone studying Earth’s history will find knowledge of these rock types crucial.
Common Limitations or Challenges
This document provides a foundational overview and identification guide. It does *not* cover the complete range of igneous rock variations, detailed geochemical analyses, or the complex processes of magma generation and eruption. It’s a starting point for hands-on learning, and further study using the referenced textbooks (Winter and Moorhouse) is expected. This preview does not include the full range of textural variations or detailed mineral compositions.
What This Document Provides
The full document includes:
* Detailed descriptions of basalt, diabase, andesite, and dacite, covering their typical mineralogy, texture, and color.
* Information on identifying specific varieties of these rocks based on texture (porphyritic, vesicular, etc.) and structure (aa, pahoehoe, columnar jointing).
* Etymological origins of the rock names.
* Geographic examples of where these rocks are commonly found.
* A list of key terms related to extrusive igneous rocks.
This preview provides a high-level overview of the document’s scope and purpose, but does not include the detailed mineral descriptions, textural classifications, or the complete list of terms found within the full lab guide.