Why Is Petrography Important?


Petrology is the study of rocks. A petrographic analysis is an in depth investigation of the chemical and physical features of a particular rock sample. A complete analysis should include macroscopic to microscopic investigations of the rock sample.

What is the importance of making petrographic reports for samples obtained in the field?

Brief Exploration Petrographic Report

This report provides identification, formal description of textures, structures and mineralogy, percentage modal estimate and significance (both economical and geological) of the sample in the suite and in relation to requested aspects.

What is a petrography answer?

Definition. Petrography. The systematic description of geological materials, their composition, and organization, in hand specimens and thin sections. Petrology. Study of the origin, structure, and composition of rocks.

What is petrography test?

Petrographic testing is the use of microscopes to examine samples of rock or concrete to determine their mineralogical and chemical characteristics. … The samples are examined through a petrological (geological polarising) microscope, using either reflected or transmitted light.

What is the difference between petrology and petrography?

Experimental petrology involves the laboratory synthesis of rocks for the purpose of ascertaining the physical and chemical conditions under which rock formation occurs. … Petrography is primarily concerned with the systematic classification and precise description of rocks.

What is the difference between petrography and petrogenesis?

The main difference between petrography and petrogenesis is that petrography involves the description and classification of rocks, especially by microscopic examination, while petrogenesis focuses on the origin and formation of rocks, especially igneous rocks.

What does Petrologist mean?

: a science that deals with the origin, history, occurrence, structure, chemical composition, and classification of rocks.

Why do we need to see mineral properties in microscope?

Most commonly, rock and mineral samples are prepared as thin sections or grain mounts for study in the laboratory with a petrographic microscope. Optical mineralogy is used to identify the mineralogical composition of geological materials in order to help reveal their origin and evolution.

What is the most commonly used device in petrography?

Equipment Used for Petrography and Thin Section

  • Geological Cutting Machine. A geological cutting machine (GEOCUT) is used for thin sectioning rocks, glasses, ceramics, minerals, concrete, etc. …
  • Precise Cutting and Grinding Machine. …
  • Grinding and Polishing Machine. …
  • Automatic Specimen Mover.

What is the mineralogical analysis?

Mineralogical analysis is the study of materials to determine mineral composition and mineral structure. This analysis can be used to identify mineral species, and understand their characteristics and properties.

What is concrete petrography?

Petrography is a branch of geology that is applied to concrete and concrete raw materials. This technique examines and evaluates the optical properties and microstructural characteristics of the materials. Petrographic analysis for concrete begins by accepting an aggregate for use in concrete (ASTM C295).


What is coal petrography?

Coal petrography is a microscopic technique used to determine a coals rank (degree of coalification) and type (amount and type of macerals) on polished specimens of minus 20 mesh prepared coal. … Rank is determined by measuring the percent light reflectance of the maceral vitrinite.

Are granite?

Granite is a light-colored igneous rock with grains large enough to be visible with the unaided eye. It forms from the slow crystallization of magma below Earth’s surface. Granite is composed mainly of quartz and feldspar with minor amounts of mica, amphiboles, and other minerals.

What are the 3 rock types?

Part of Hall of Planet Earth. There are three kinds of rock: igneous, sedimentary, and metamorphic. Igneous rocks form when molten rock (magma or lava) cools and solidifies. Sedimentary rocks originate when particles settle out of water or air, or by precipitation of minerals from water.

What do you mean by prospectors?

noun. a person who searches for the natural occurrence of gold, petroleum, etc.

Who is the father of petrology?

The Scottish geologist Sir James Hall (1761–1832) is considered to be the father of experimental petrology.

What is volcanic texture?

Igneous textures include the rock textures occurring in igneous rocks. … Glassy or vitreous textures occur during some volcanic eruptions when the lava is quenched so rapidly that crystallization cannot occur. The result is a natural amorphous glass with few or no crystals. Examples include obsidian.

Is a geologist a scientist?

Geologists are scientists who study the Earth: its history, nature, materials and processes. There are many types of geologists: environmental geologists, who study human impact on the Earth system; and economic geologists, who explore for and develop Earth’s resources, are just two examples.

What are the three main branches of petrology?

Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly taught together because they both contain heavy use of chemistry, chemical methods, and phase diagrams.

How do I become a Petrologist?

What Are the Education Requirements to Become a Petrologist? Petrologists require a bachelor’s degree at minimum to lock down entry-level positions in the field. Majoring in geology or geosciences is recommended, though physics, chemistry, or biology may also be accepted if take in conjunction with geology courses.

Why do petrographic microscopes have polarizers?

Petrographic microscopes are constructed with optical parts that do not add unwanted polarizing effects due to strained glass, or polarization by reflection in prisms and mirrors. … Using one polarizer makes it possible to view the slide in plane polarized light; using two allows for analysis under cross polarized light.

How does a petrographic microscope work?

In the petrographic microscope, the light is collimated by the condenser into a bundle of beams,all parallel to the optical aids of the microscope. … The light beams are polarized in one direction (by the polarizer) before the light reaches the specimen. This light is called plane polarized light.