Organic geochemical and stable carbon isotopic investigation of coals formed in low-lying and raised mires within the Eastern Alps (Austria)

Stratigraphic distribution of macerals and biomarkers in the Donets Basin: Implications for paleoecology, paleoclimatology and eustacy

“…This pattern is characteristic for the presence of bacteria in the swamp (Ourisson et al, 1979) and for an oxic-type environment (Philp and Mansuy, 1997). The hopanes / steranes ratio allows estimation of the relative abundance of bacteria versus algae and terrestrial higher plants (Boreham et al, 1994;Bechtel et al, 2001). This ratio is high in our samples from coals, marine claystones and deltaic siltstones, suggesting high bacterial activity or best preservation in these environments.…”

Optical and geochemical characterization of Upper Sinemurian (Lower Jurassic) fossil wood from the Lusitanian Basin (Portugal)

“…For example, Gröcke (1998) suggested that wood diagenesis in different lithological contexts would lead to a negative correlation of δ 13 C with C, whereas Schleser et al (1999) suggested that in more advanced stages of thermal degradation, the initial depletion of 13 C is overprinted by the loss of certain compounds (e.g., volatiles). During microbial activity, thermal degradation and coalification δ 13 C is expected to increase (Teichmüller and Teichmüller, 1979;Bechtel et al, 2001). In addition, Brodie et al (2011) demonstrated that different acid pre-treatments, residual inorganic carbon contents and the organic matter state and composition can affect the C/N, δ 13 C, and δ 15 N values of organic matter.…”

“…The increase of δ 15 N in wood has been associated to N fertilization and/ or changes in drainage patterns, which are known to increase soil N dynamics and thereby increase soil, leaf, and wood δ 15 N. In addition, diagenesis and coalification also have the capability to change the original δ 15 N of fossil wood. During the initial stages of wood decomposition, the processes of mineralization (sensu Kanduč et al, 2005) and anaerobic bacteria decomposition following fungi aerobic activity are expected to occur (e.g., Bechtel et al, 2001Bechtel et al, , 2003, leaving the residual organic matter depleted in 14 N (Rimmer et al, 2006). The isotopic composition is then expected to remain stable until the onset of the bituminous stage (Boudou et al, 1984).…”

“…From the above, it seems most likely that the high δ 15 N of fossil wood samples was the result of microbial activity (see Rimmer et al, 2006) during the initial stages of wood decomposition and burial. It has been suggested that gelification and humification may be microbiologically mediated (Bechtel et al, 2001(Bechtel et al, , 2003Rimmer et al, 2006).…”

A short report of the investigations made on the facies of Austrian coal deposits

“…Ongoing studies using biomarkers and C-isotopes and their combination with petrogra- Klaus (1954), Pohl (1970), Meller (1998), Kolcon and Sachsenhofer (1999), Bechtel et al (2002a,b) phy (and palynology) yield additional information on the coal-forming environments and the early diagenetic fate of the biomass (e.g. Bechtel et al, 2001bBechtel et al, , 2002aBechtel et al, ,b, 2003. A combination of paleontology, petrology, and geochemistry was also used to reconstruct the depositional environment of Upper Cretaceous jet (Kollmann and Sachsenhofer, 1998;Bechtel et al, 2001a) (Table 1).…”