We suspect presence of biogenic pyrite in our recently collected lake sediments. Does these sediments needs any specific sampling storage or analytical treatments before further analyses on biogenic pyrite.
Any advice on this aspect will be a great help for us. Thank you in advance.
Anoop
Anoop:
Framboidal Pyrite of biogenic origin could be processed as per the method described in this link:
Best
Syed
Article Pyrite framboids from buried paleo estuary off Chilka Lake, Odisha
As mentioned Above Framboidal Pyrite is the under microscopic form of organic sulfur in Organic Rich Source Rock or other carbonaceous rich sediments. After the analysis of sulfur as sulfide, sulfate, and organic sulfur. the latter organic sulfur in your case will not exceed than 2% dry Ash Free Basis in case of fresh water circumstance however in brakixh or marine intruder water this value will be much higher can reach to 6-to 7 % of organic sulfur on dry Free Basis. So researcher make relationship between organic sulfur and type of Organic matter like vitrinite , liptinite and inertinite like C-L. Chou, Geochemistry of sulfur in coal. In: Orr, WL, White, CM (Ed) Geochemistry of Sulphur in Fossil Fuels. Amer. Chem. Soc., Washington D.C., ACS Symposium series, v. 429, 1990, pp. 30–52.
Dear Mr. Ambili,
I refer to these papers for the recognition of biogenic pyrite:
DILL, H. G. and KEMPER, E. (1990) Crystallographic and chemical variations during pyritization in the Upper Barremian and Lower Aptian dark claystones from the Lower Saxonian Basin (NW Germany). - Sedimentology 37: 427-443.
DILL, H. G., EBERHARD, E. and HARTMANN, B. (1997) Use of variations in unit cell length, reflectance and hardness determining the origin of Fe disulphides in sedimentary rocks.- Sedimentary Geology, 107: 281-301.
DILL H.G., WEHNER, H. and BLUM, N. (1993) The origin of sulfide accumulation in arenaceous rocks beneath carbonaceous horizons in fluvial depositions of late Paleozoic through Cenozoic age (SE-Germany). - Chemical Geology, 104: 159 – 173.
Keep your samples moist and prevent them from drying out in this case you will get a series of poorly-crystallized sulfate minerals and your ensuing analyses will result in a false data set be it mineralogical or chemical. The finer the pyrite aggregates and the more complex the crystal morphology the more vulnerable the pyrite samples are to atmospheric changes.
Good luck
H.G.Dill
Store your sample in cool place. some pyrite crystals are susceptible to environmental changes specially in hot environment.
I lose my some sample during SEM-EDS analysis
Thanks
Dhananjay
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