Conclusion

Light and electron microscopic and microprobe imaging of the Permian - Triassic boundary section in the Spiti Himalayas provides clues to a rapidly changing environment in this section of the Tethys sea. Some of them may be summarized as:

1. The Spiti section may represent a continental - marine transitional coastal area, characterized by the presence of framboidal pyrites and grey shales.

2. The size variation of framboidal pyrites and the changing composition of the lithology reflects changing oxidation state of the environment, indicating anoxic conditions during the end Permian.

Thus, Electron microscopy in conjunction with light micrscopy can be used as a useful tool to decipher and understand past environmental conditions, some of which can bring life to the brink of extinction.

 

References

Shen, W., Y. Lin, et al. (2007). "Pyrite framboids in the Permian-Triassic boundary section at Meishan, China: Evidence for dysoxic deposition." Palaeogeography, Palaeoclimatology, Palaeoecology 253(3-4): 323-331.

Shukla, A. D., N. Bhandari, et al. (2002). "Chemical signatures of the Permian-Triassic transitional environment in Spiti Valley, India." Geological Society of America Special Papers 356: 445-453.

Wignall, P. B., R. Newton, et al. (2005). "Pyrite framboid evidence for oxygen-poor deposition during the Permian-Triassic crisis in Kashmir." Palaeogeography, Palaeoclimatology, Palaeoecology 216(3-4): 183-188.