Dear Dr. Ekoa,

it can be referred to high TOC, carbonate- or the minerals bearing hydroxyl groups or water. Without a knowledge of the overal chemical composition of your lacustrine samples it would be mere speculation. I also advise you to have a closer look at you mineral assemblage. A combination of mineralogy and chemistry will help you gain more information.

H.G.Dill

Great thanks dear prof. Am still waiting for mineralogy and COT results to confirm your suggestions.

Both the above answers are sufficient. Rocks rich in carbonate and hyroxyl-bearing minerals would give high values of LOI. Why don't you run your samples on XRD? That may provide a more precise explanation.

Hi Armel,

At what temperature did you conduct your LOI measurements? This is one of the best references regarding LOI in lake sediments: Article Loss on Ignition as a Method for Estimating Organic and Carb...

Sebastien

Thanks dear Qasim, I have already perfomed XRD and waiting for results.

Great thanks

Hi Sebastien,

Thanks for this interesting article. It will help me. LOI in my samples where measured at 1000 °C.

Dear Mr. Ekoa,

this standard procedure used in some branches of the industry or mining may be too high a temperature of reaction and in sedimentology and pedology it is often wiser to apply a lower temperature of approx. 110°C. It strongly depends on the scope of your analysis. In case of lake sediments in my opinion you use a "cannon to shoot a sparrow".

With kind regards

H.G.Dill

Please which interpretation can I give to high LOI (loss on ignition) values (>20%) in Lake sediments ?

I think You can explain it of high content of smectite, especially in fine grained sediments.

Armel, since you measured LOI at 1000°C, your high values could be due to organic matter, carbonates, or both. For lake sediments, we generally do LOI at 550°C first (organic matter content), and then at 950 or 1000°C (the weight loss between 950 and 550°C is mostly due to carbonates). Clay minerals (eg smectite) could contribute a bit but LOI values of 20% or above can only be explained by the presence of organic matter and/or carbonates. LOI550 or TOC measurements would allow you to tell them apart.

Great thanks Sebastien. I will make COT to confirm.

Clay minerals (eg smectite) could contribute a bit , but

Smectite has one of the most high sorbented ability for organic matter. I have LOI about 30% in sediments of Uglovoe Bay (Japan Sea).

Hi Dr Anatoly,

Am very happy for you answer.

Please can I have your paper in sediments of Uglovoe Bay in Japan see?

Sincerely

On this site

Pacific geology, № 2. 1983. С. 93-96. Mozherovsky AV, Pliss SG, Sorochinsshya AV, Tolok KP, Gramm-Osipov LM, Gusev VV FEATURES OF THE BOTTOM SEDIMENTS FORMATION IN THE UGLOVOE BAY (SEA OF JAPAN)

With best wishes

Great thanks

High LOI in lake sediments is because of organic matter.