| More

ORGANIC GEOCHEMISTRY OF HUMIC ACIDS FROM A NEOGENE LIGNITE SAMPLE, BULGARIA

Views: 149 Downloads: 120
M. Stefanova, S.P. Marinov
M. Stefanova, S.P. Marinov

Abstract


Humic substances naturally occur in Miocene/Pliocene-aged lignite at very high concentrations. Here biomarkers in the bitumen-free extract of humic acids from Thracian lignite, Bulgaria, are studied. Applying methods of organic geochemistry a broad range of compounds are isolated and characterised. Species are classified according to abundance, possible source input and diagenetic transformation. A feature of humic acids derived from Thracian coal is the extremely high content of 16α(H)Phyllocladane, ~60% of aliphatic fraction, or 1.6 wt.% of initial lignite. The high diterpenoids content, especially with abietane skeleton, proved the conifer contribution to the peat-forming helophytes, i.e. Cupressaceae s. str., Podocarpaceae, Araucariaceae, Taxodiaceae, Phyllocladus, Piceae. Tightly-trapped, linear long-chain fatty acids (FAs) are the main constituents of the acidic fraction of humic acids. Their distribution patterns indicate a dominant higher plant origin. The presence of αOH-FAs and hopanoid acids assumes bacterial activity in the plant material reworked. A hint for the input of plant biopolymers, i.e. cutin, suberin, is the relative high content of “even” carbon numbered ωΟΗFAs and α,ω-alkanedioic FAs. “Even” numbered short-chain ωΟΗFAs could originate from cutin-derived constituents of the needles of numerous species of gymnospermous families.


Keywords


Thrace; lignite; humic acid; biomarker; fatty acid; palaeoenvironment;

Full Text:

PDF

References


Allard, B. 2006. A comparative study on the chemical composition of humic acids from forest soil, agricultural

soil and lignite deposit. Bound lipid, carbohydrate and amino acid distributions. Geoderma 130, 77-96.

Amblès, A. 2001. Methods to reveal the structure of humic substances. In: Hofrichter, M., Steinbüchel,

A. (Eds) Biopolymers.Wiley-VCH. v.1 pp. 325-348.

Bechtel, A., Sachsenhofer, R.F., Zdravkov, A., Kostova, I., Gratzer, R. 2005. Influence of floralassemblage,

facies and diagenesis on petrography and organic geochemistry of the Eocene Bourgas coal and the

Miocene Maritza-East lignite (Bulgaria). Organic Geochemistry 36, 1498-1522.

Cranwell, P.A. 1982. Lipids of aquatic sediments and sedimenting particules. Prog. Lipid Res. 21, 271-308.

Deport, C., Lemée, L., Amblès, A. 2006. Comparison between humic substances from soils and peats

using TMAH and TEAAc thermochemolysis. Organic Geochemistry 37, 649-664.

Grasset, L., Amblès, A. 1998. Structural study of soil humic acids and humin using a new preparative thermochemolysis

technique. J. Anal. and Applied Pyrolysis 47, 1-12.

Grasset, L., Guignard, C., Amblès, A. 2002. Free and esterified aliphatic carboxylic acids in humin and

humic acids from peat sample as revealed by pyrolysis with TMAH or TEAAc. Organic Geochemistry

, 181-188

Guignard, C., Lemée, L., Amblès, A. 2005. Lipid constituents of peat humic acids and humin. Dis-tinction

from directly extractable bitumen components using TMAH and TEAAc thermochemolysis. Organic

Geochemistry 36, 287-297.

Hashimoto N., Aoyama T., Shiori T. 1981. New methods and reagents in organic synthesis. 14. A simple

efficient preparation of methyl esters with trimethylsilyl diazomethane (TMSCHN2) and its

application to gas chromatographic analysis of fatty acids. Chemical Pharmaceutical Bulletin 29,

-1478.

Kolattukudy, P.E. 1976. Chemistry and biochemistry of natural waxes, Elsevier, Amsterdam.

Kolattukudy, P.E. 1980. Biopolyester membranes of plants: cutin and suberin. Science 208, 990-1000.

Lehtonen, K., Hänninen, K., Ketola, M. 2001. Structurally bound lipids in peat humic acids. Organic

Geochemistry 32, 33-43.

McCarthy, R.D., Duthie, A.H. 1962. A rapid quantitative method for the separation of free fatty acids

from other lipids. J. of Lipid Res. 2, 117-119.

Oros, D.R., Standley, L.J., Chen, X., Simoneit, B.R.T. 1999. Epicuticular wax composition of predominant

conifers of western North America. Z. Naturforsch. 54c, 17-24.

Šiškov, G.D. 1997. Bulgarian low rank coals: geology and petrology. In: Gayer, R. and Pešek, J. (eds),

Eur. Coal Geology and Technol. Geol. Soc. Spec. Publ. 125, 141-148.

Stefanova, M., Velinova, D., Marinov, S.P., Nikolova, K. 1993. The composition of lignite humic acids.

Fuel 72, 681-684.

Stefanova, M., Magnier, C., Velinova, D. 1995. Biomarker assemblage of some Miocene-aged Bulgarian

lignite lithotypes. Organic Geochemistry 21, 1067-1084.

Stefanova, M., Oros, D.R., Otto, A., Simoneit, B.R.T. 2002. Polar aromatic biomarkers in the Miocene

Maritza-East lignite, Bulgaria. Organic Geochemistry, 33, 1079-1091.

Válkova, D., Grasset, L., Amblès, A. 2009. Molecular compounds generated by RuO4 oxidation and

preparative off line thermochemolysys of lignite humic acids from South Moravia: implication for molecular

structure. Fuel 88, 2113-2121.

Wang, T.-G., Simoneit, B.R.T. 1990. Organic geochemistry and coal petrology of Tertiary brown coal. 2.

Biomarker assemblage and significance. Fuel 69, 12-20.


Refbacks

  • There are currently no refbacks.


Copyright (c) 2017 M. Stefanova, S.P. Marinov

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.