MAGMATIC CONCENTRATION

1.INTRODUCTION

During the crystallisation of a magmatic melt,many minerals of economic value also get formed depending on the original composition of the melt .These minerals may get concentrated towards the bottom or margins or other places within the cooling body of magma because of some factors operating at the time of crystallisation these deposits are called magmatic concentration.

This figure contains:

•Presence of magma inside the earth surface

•Cooling process of water near the earth surface

•Presence of different metal mineral in different fissures

•Process of conversion of magma into lava at the surface of earth

The figure contains :

•Presence of different metal inside the earth surface

•It shows the area of different sulfidation process

•Presence of different iron ore such as hamaetite,magnetite along with the presence of pyrite

•Most importantly it shows the different possibility of composition of different metal inside the earth surface.

2.SOME FACTS ABOUT MAGMATIC CONCENTRATION

• These concentrations are some times of such size and nature that their economic exploitation is feasible .

• Magmatic concentration form major source of some important metals such as Gold,chromium,titanium and uranium.

• Magmatic concentration may take place during the earlier or the late stages of the process of crystallisation these are often distinguish as early or late magmatic crystallisation.

• Their stage of formation is easily revealed by their relationship with the closing rocks.

FORMS OF OCCURANCE OF MAGMATIC DEPOSITS

1. segregations

In magmatic segregations economic minerals get concentrated more or less at the place of their formation such as along bottom or margins of an igneous body. In the earlier stages of crystallisation,when most of the magma is still in a molten state,minerals that happen to form sink to and settle at the bottom due to gravity.

•First figure shows the process of magmatic concentration along with the formation of volcano.

•Second figure shows the presence of different mineral composition inside the earth surface along with the percentage presence of nickel.

•SOME DEFFENITION RELATED TO MAGMATIC SEGREGATIONS

•Gravitative settling- the process of deposition of economic mineral towards the bottom of the igneous body due to gravity is called gravitative settling.

•Residual magmatic concentration- In later stage of crystallisation,when most of magma has crystallised into solid rock ,some left over melt containing economic mineral crystallises along the margins of the solidify magma .This process is reffered as residual magmatic concentrations.

2. Magmatic dissemination

s In magmatic desseminations,the economic minerals are dispersed at random in a cooled igneous body.In some cases the dispersion is within a limited space where as in other cases it occurs over a large volume when concentration is economically not exploitable.

•SOME FACTS ABOUT MAGMATIC DESSEMINATIONS

•When the mineral of economic value is despersed only in a limited space in the body of igneous mass and trend is common over large area,whole of the rock mass is mined for exploitation and extraction of the of the valuable mineral.

•Diamond desseminations are a typical example of magmatic desse minations.

•Kimberlites-In the famous diamond pipe of south africa where the minerals occurs as dispersed crystals in ultrabasic rocks is called kimberlites

3. Magmatic

injections

These are thin lenticular or slightly tabular bodies of magmatic minerals that appear as having been injected into the host rocks.When magma rises up with sufficient hydrostatic force,it may intrude into available fissures and fractures in the surrounding deposit may result both as early and late stages crystallisation.

THANKING

YOUPresented by:

Name roll no.Vikash mishra 14Salim Akhtar 23Abdul monaf 29