Carbonate Petrography
Carbonate petrography is the study of limestones, dolomites and associated deposits under optical or electron microscopes greatly enhances field studies or core observations and can provide a frame of reference for geochemical studies.
25 strangest Geologic Formations on Earth
The strangest formations on Earth.
What causes Earthquake?
Of these various reasons, faulting related to plate movements is by far the most significant. In other words, most earthquakes are due to slip on faults.
The Geologic Column
As stated earlier, no one locality on Earth provides a complete record of our planet’s history, because stratigraphic columns can contain unconformities. But by correlating rocks from locality to locality at millions of places around the world, geologists have pieced together a composite stratigraphic column, called the geologic column, that represents the entirety of Earth history.
Folds and Foliations
Geometry of Folds Imagine a carpet lying flat on the floor. Push on one end of the carpet, and it will wrinkle or contort into a series of wavelike curves. Stresses developed during mountain building can similarly warp or bend bedding and foliation (or other planar features) in rock. The result a curve in the shape of a rock layer is called a fold.
Sedimentology
Ore forming processes
Ore forming processes
Magmatic process
Layered plutons
- As magma solidifies (plutonic) its temperature gradually decreases. Minerals crystalize first in the liquid magma. Some crystals are denser than the magma which will settle down and is concentrated at the bottom which is also called crystal settling.
- In the mafic magma crystallization usually starts from the bottom so early forming minerals are concentrated at the base.
- When these processes occur and form minerals, at some time different magma can enter these mineraliztion which can change the early minerals formed.
Kimberlites
Volcanic vent deposits
Hydrothermal process
- Magmas of granitic composition when solidifies leaves a water-rich residual fluid which precipitates and form ore body.
- In active volcanic activities when ground water seeps down through the crust, these magma chamber heats the water which provides the hydrothermal solution. This hydrothermal solution is at shallow depths and its precipitation makes an ore.
- Sea water is heated when it seeps along cracks in the oceanic crust mostly at the mid oceanic ridges and submarine volcanoes.
- Hydrothermal vein deposits are formed when these hydrothermal solutions enter a country rock along cracks and fractures. It precipitates in the parent rock in a vein like structure.
- The hydrothermal solution in vein deposits can also soak through the country rock which for disseminated ore deposits. This is less concentrated but as formed with the vein together they form economical deposit.
- Disseminated copper depoits are associated with porphyry copper deposits. This depoist is associated with granitic to dioritic composition.
Sedimentary process
Sedimentary sorting
Precipitation
Weathering process
Metamorphic process
Metamorphic rocks form by heat and pressure altering mineralogy and it can also expel water from the rocks. This water due to heat makes hydrothermal deposits so they are also associated with metamorphismMass Wasting
Factors
Steepness of the slope
Types and orientation of rocks
Nature of unconsolidated materials
Water and vegetation
Mass wasting types
Flow
Creep
Debris flow, mud flow and earth flow
Solifluction
Slide
Slump
Rockslide
Fall
Earthquakes
Earthquake waves
Body waves
Surface waves
Ground water
Groundwater
Characteristics
Porosity and permeability
Water table
Movement of ground water
Springs
Artesian wells
Ground water depletion
Geochemical Sampling
What is geochemical sampling?
Geochemical sampling is taking a small portion of Earth's material for finding its mineralogy, composition and grade such that it represent the whole area. Geochemical sampling is the basic technique used for the exploration of minerals and their ores. So for this exploration multiple sampling techniques can be used to determine the place of ores. There are several methods of sampling- Stream sampling
- Vegetation sampling
- Hydrogeochemistry
- Soil sampling
- Gas sampling
- Rock sampling
Stream sampling
Vegetation sampling
Geobotanical survey
Biogeochemistry
Hydrogeochemistry
Soil sampling
- Residual soil
- Exotic soil
Residual soil
Exotic soil
Gas sampling
Rock sampling
Depositional Environments
- Continental
- Terrestial
- Marine
Continental
- Glacial
- Lacustrine
- Fluvial
- Dessert
Glacial
Lacustrine
Fluvial
Dessert
Terrestial
- Delta
- Lagoon
- Beach
Delta
Lagoon
Beach
Marine
- Continental shelf
- Continental slope
- Open marine