Jarosite Luminescent Clock: Indian Mars Dating Study
Why in the news
Indian scientists showed that jarosite, a mineral common on Mars, records geological events like a clock, aiding planetary dating and environmental studies.
Key facts
- Jarosite works as a natural radiation clock for events within 25,000 years.
- Formula: KFe₃(SO₄)₂(OH)₆.
- Luminescence survives up to 450°C, so rovers could date samples with heaters and LEDs without damaging them.
Profile and occurrence
| Aspect | Detail |
|---|---|
| Crystals | Trigonal; brittle; dark yellow to yellow-brown; Mohs hardness 2.5-3.5 |
| On Earth | Arid zones, acid mine drainage, Antarctic ice cores, acidic soils such as Kachchh (India) |
| On Mars | Seen by three NASA rovers; signals oxidising, acidic conditions |
Uses
- Dating tool for Mars events.
- Indicator of oxidation stages in mining and glacial areas.
- Marker for ice-age layers in deep core samples.
Exam angle
- Mineral formula: KFe₃(SO₄)₂(OH)₆.
- Dating window: 25,000 years.