| Kerogen is the ... part of sedimentary organic matter. Difficult to characterize but likely a heterogeneous, complex polymeric structure. | insoluble |
| Sources for kerogen can include biopolymers already present in some algae (algaenan) and higher plants (cutan) which are resistant against diagenesis - which pathway is ths? | the selective preservation pathway |
| Another pathway, aside from the selective preservation pathways, is geopolymerization, what does this entail ? | Functional molecules can react under de influence of light and oxygen (oxidative polymerization, jetification) or sulfide (vulcanization) to form geological polymers (“Geopolymerization”) |
| what is kerogen? | The insoluble part of the organic matter (90%), likely largely consisting of polymers -> makes oils |
| The amount of uncharacterized stuff in organic carbon such as kerogen ... deeper in the sediment | increases |
| What was the speculative view of kerogen structure (early 80’s) | They are lipids but random polymerization of low molecular weight compounds: “Geopolymerization” leading to non-extractable material. Happens in geosphere, after death of organism, something is catalysing this process. |
| What 3 types of analyses may be performed on kerogen? | elemental analysis, solid state spectroscopic analysis, chemical analysis through flash pyrolisis |
| with elemental analysis we mean? | simply a count of elemental ratios of H/C and O/C -> know potential to create oil and the basics of where it is coming from |
| Solid state nmr can give us information on... | functional groups, relies on spin resoncance of 13C and how it is affected by its neighbours. It gives an overall average |
| Chemical analysis may be performed if we use smaller fractions of the kerogen polymers, how could we get these? | flash pyrolisis, thermal depolymerisation which makes the polymer fall apart and can now be analysis with Gc/Ms |
| The biopolymer algaenan was proof that... | it was ot only through geopolymerization that these kerogens were formed, because the algaenan was also making up the algal cell walls of life eustihmatophytes (biomarker = long chain diols). So selective preservation of algaenan |
| What is algaenan | polymer (insolublle) from outside of cell wall (mainly green algae such as eustigmatophytes and botryococcus braunii) that is very resistant to degradation. Structure of longchain diol monomers connected through ester and ether bonds. |
| why is this (algaeanan) selective preservation? | Only a few algae make these cell walls and are able to survive for millions of years -> Green algae! (not diatoms and haptophytes so their cell walls will not accumulate and preserve over time) |
| what biopolymers do higher plant leaf ans term cuticles make? | cutin and cutan (and suberin) |
| what biopolymers do spores and pollen walls make? | sporopollenin |
| What is cutin? | It is a hydrolysable polymer present in the leaf and stem cuticles of plants. they contain labile (weak) esterbonds (know because upon hydrolysis they released ester (C16/18) bonded hydroxy fatty acids). Mainly longchain fatty acids and alcohols. |
| What is cutan ? | Insoluble, non-hydrolysable, aliphatic biopolymer of plant cuticles. It is very resistant to degradation and cant be destroyed throuhg simple hydrolisis. It is mainly found in CAM plants (drought adapted) and formed a hydrophic cuticle layer (aliphatic = hydrophobic, long alkanes and alkene, Cs and Hs) |
| a 3D strucutre such as the cutan biopolymer leaves the molecules | more insoluble |
| Cuticles of most plants are of a mix of ..... (hydrolysable polymer) and ....(insoluble) - but can be 100% of one | cutin & cutan |
| drought stress proxy (maybe) | cutan |
| what is sporopollenin | polymer in spores and pollen walls, a biopolymer consisting of p-coumaric acid and some ferulic acid building blocks |
| sporopollin looks like lignin, what is lignin? | Lignin is an insoluble biopolymer occurring in higher plants. In particular wood consists of lignin and cellulose |
| why do lignin and sporopollenin look alike? | Pathway for lignin and sporopollenin are close to each other, slightly different monomers, but the biosynthetic pathways are very closely related -> similar buildingblocks |
| Geopolymerisation ooccurs in the ... | natural environment after cell death |
| natural vulcanisation is a type of gepolymerisatio, what doesit entail? | It relies on the intra- versus intermolecular incorporation of sulphur to make polymers |
| oxidative polymerization is another type of geopolymerization , what does it entail? | Forming “geopolymers” from unsaturated lipids during diagenesis under influence of light and oxygen |
| what is jetification | polymerization of a polyme, oxidative “polymerization” of fossil lignin upon exposure to oxygen (cross polymerization) |
| No aliphatic signal in modern material of mega spores, but in fossilized megaspores we do see an aliphatic signal created during fossilization - what is this evidence for? | geopolymerizatoion |
