What is the hydrothermal alteration?

What is the hydrothermal alteration?

Hydrothermal alteration is defined as any alteration of rocks or minerals by the reaction of hydrothermal fluid with preexisting solid phases.

Where is hydrothermal alteration most common?

the oceanic crust
Hydrothermal alteration of the oceanic crust is widespread and locally thorough in oceanic crust (Scambelluri et al., 1995), resulting in the pervasive serpentinization of ultramafic rocks as witnessed in many ultramafic sections in ophiolites.

What are the types of alteration?

Types of alterations

• Potassic alteration.
• Phyllic (sericitic) alteration.
• Propylitic alteration.
• Argillic alteration.
• Silicification.
• Carbonatization.
• Greisenization.
• Hematitization.

What is an alteration zone?

Alteration zones are developed in a wide range of geological milieus such as volcano-plutonic rocks. Hydrothermal alteration zones are considered an important guide for mineral exploration and can act as a potential zone of mineralization.

Is Serpentine an alteration product?

Serpentine is generally an alteration product of olivine or other mafic minerals. It is frequently found with oxides and often with talc, chlorite, or other Mg-rich silicates. Serpentine may be patchy, scaley, fibrous or blocky.

How is epidote formed?

Description: Epidote is a common mineral formed during low grades of metamorphism and hydrothermal activity. It is particular common in metamorphosed basalts and gabbros where it replaces plagioclase, pyroxene and olivine. It can also be found in schists and marbles.

Why is epidote green?

In that series, the iron of epidote is gradually replaced by aluminum to the end member clinozoisite composition of Ca2Al3(SiO4)(Si2O7)O(OH). Clinozoisite is usually lighter in color than epidote because iron is what produces epidote’s greenish to brownish color. X is one of these rare earths: Ce, La, Nd, Y.

How do you determine alterations?

A document examiner will use a variety of techniques including alternate light sources, magnification, detection of indented impressions, side lighting, transmitted lighting, and others in a non-destructive method to examine the document for characteristics indicative of alterations.

What is alteration of rocks?

Rock alteration usually involves chemical weathering in which the. mineral composition of the rock is changed, reorganized, or redistributed. The rock minerals are exposed. to solution, carbonation, hydration, and oxidation by circulating waters. These effects on the mineral.

What is an alteration system?

System Alteration means a change to one Party’s System, plant or apparatus or equipment otherwise used in connection with that System, which is such as to materially affect or impact the operation of the other Party’s System, plant, apparatus or equipment used for the conveyance of Calls/Messages as contemplated by the …

Is Jade a serpentine?

Serpentine may be confused with jadeite or nephrite because of its similar coloration, and is sometimes known as ‘Koren jade’, ‘serpentine jade’ or ‘new jade’. Serpentine however, is softer and scratches more easily than true jade, but it is often used as a jade substitute.

What is the chemical composition of epidote?

epidote, any of a group of colourless to green or yellow-green silicate minerals with the general chemical formula A2B3(SiO4)(Si2O7)O(OH), in which A is usually calcium (Ca), though manganese (Mn) or cerium (Ce) is sometimes substituted, and B is generally aluminum (Al), with the main substitution being ferric iron (Fe …

Is epidote a rare mineral?

This very rare mineral occurs in small grains.

Is green tourmaline the same as epidote?

Epidote displays the distinctive features of being yellow-green in color, with a prismatic habit. However, the stone can still be mistaken for tourmaline. Upon closer inspection however, tourmaline lacks the cleavage that epidote has, and tourmaline has a hexagonal or triangular cross section which epidote does not.

How is obliterated writing detected?

Commonly obliterated writing is detected using spectroscopic image in which light transmits through the obliterated writing and is absorbed by the overwritten or masked writing.