Kelli:

You may have a look at this link and the references therein for insight:

Best

Syed

Dear Kelli,

You can find a list of bibliographical references presenting cases of soot (and/or micro-charcoals) trapped into concretions in this paper : https://doi.org/10.1016/j.quaint.2017.10.031

I hope this will be helpful :-)

here is the ref : Vandevelde, S., Brochier, J.É., Desachy, B., Petit, C., Slimak, L., 2017. Sooted concretions: A new micro-chronological tool for high temporal resolution archaeology. Quaternary international.

See especially Fig.1 and Tab.1

here is the full text

I believe the J. Desmarchelier et al., 2004 paper is the one I am looking for. Thank you Ségolène!