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Context

Jarosite samples from Kachchh, Gujarat, a region with terrain conditions similar to Mars, were investigated in a recent study by a team of researchers from India.

What is Jarosite?

Jarosite is a yellow-brown mineral that is frequently discovered in arid, saline environments. It is composed of potassium, iron, and sulphate. The objective of the investigation was to evaluate the potential of jarosite to function as a "natural clock" on Mars by monitoring geological events through radiation-induced luminescence.

How was Jarosite found in Antarctica?

Scientists set out to explore minerals in deep ice cores. It would have helped them understand ice age cycles. Italian University of Milano-Bicocca researchers led it. The researchers discovered an unusual mineral while examining TALDICE, a 5,315-foot deep ice core in Talos Dome, East Antarctica. The scientists next used X-ray absorption and electron microscopy to determine that this yellow-brown material is jarosite.

Scientific Methodology and Luminescence Testing

Sample Location	Kachchh
Sample Type	Six jarosite vein samples
Dating Technique	Luminescence dating
What is Luminescence?	Light emitted by minerals when they release stored energy from natural radiation
Preparation Step	Grains washed with weak acid to enhance brightness
Analysis Process	Irradiating → Heating → Cooling → Repeating cycle
Observed Emissions	Four distinct luminescent emissions
Emission Temperatures	100°C, 150°C, 300°C, 350°C
Thermal Stability Indicator	Emissions observed even after heating up to 450°C

Why Kachchh, Gujarat, Was Chosen

The Kachchh region in Gujarat was chosen because of its high aridity and salinity, which resemble Martian topographical conditions. This makes it an appropriate analog site for testing the behavior of jarosite in extraterrestrial-like conditions.

Source: The Hindu

Practice Question:

Q. Consider the following statements about Jarosite:

Jarosite is a hydrous sulfate mineral containing potassium and iron.
It is typically formed in arid, oxidizing environments such as acid mine drainage areas.
Evidence of Jarosite has been found on Mars, suggesting the presence of water in the past.

Which of the statements given above is/are correct?

A. 1 and 2 only
B. 2 and 3 only
C. 1 and 3 only
D. 1, 2 and 3

Correct Answer: D. 1, 2 and 3

Explanation:

Statement 1 is correct: Jarosite is a potassium iron sulfate mineral.
Statement 2 is correct: It forms in oxidizing, acidic, and water-limited conditions—common in mining areas.
Statement 3 is correct: NASA's Mars rovers have discovered jarosite on Mars, supporting theories of ancient water activity