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hey thank you good morning um so the

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study out I want to present to you now

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Islam actually um in situ um isotopic

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analysis of carbon isotope in organic

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matter from the Church of the dresser

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formation in the pill rock python which

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are dated to 3.5 billion years and

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contains some of the oldest evidence for

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life on Earth um so the Pilbara cretonne

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is well known not just as the site of

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occurrence to my delight but as the

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location of Earth all this putative

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stromatolites and microfossils um the

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beautiful stromatolite of the sturdy

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these are probably of biogenic origin I

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don't think a lot of people dispute that

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now slightly older are the putative

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microfossils that were found in the

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famous a textured whose biogenic origin

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has been debated for over 30 years now

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the oldest purity of stromatolites and

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microfossils occur in the bed Church of

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the dresser formation data to 3.5

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billion years all those a biogenic

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origin of these oldest structures have

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also been debated there are isotopic

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evidence that support microbial so for

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this proportion ation in microbial

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methanogenesis in this rocks and another

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important of division is the occurrence

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of organic matter in association with

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these alleged biogenic structures which

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also support some kind of link that

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these are actually produced by biologic

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activity bulk carbonized topic analysis

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of the organic matter that is preserved

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in these rocks have shown that it is

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depleted in carbon 13 in a manner very

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similar to that of organic matter

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produced by autotrophic microorganisms

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suggesting that it is of biogenic origin

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however experimental studies have shown

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that similar isotopic composition can be

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obtained during a biotic carbon fixation

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in processes which are similar to the

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industrial future crop type synthesis

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which I will talk about a little I talk

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about it a little later and therefore

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they concluded that carbon isotopic

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composition of organic matter by itself

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is not a conclusive evidence for a

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biogenic origin so in an attempt to

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better constrain to the origin of the

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organic matter preserved in these rocks

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in this church we have decided to apply

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in situ carbon isotopic analysis of the

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organic matter and this technique has

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the potential of distinguishing between

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different generations in now of organic

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matter in the same sample like you see

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here from the sturdy full formation work

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by the fault at all they have found

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within one sample organic matter in the

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form of these globular clusters and

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spheres and they have shown that it has

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slightly different carbon isotopic

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composition now if you will do bulk

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analysis for this sample so you might

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just get an average which kind of

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obscure the real picture so like the

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work shown here our work would also done

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in the whisk seems lab which you have

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probably visited and Sunday now we have

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used a standard of natural church that

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contain organic matter which allow us to

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accurately correct with instrumental

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mass bias unlike previous works who have

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targeted microstructures in this sample

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which have used crystalline graphite we

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who now is known to have a different

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instrumental our bias so our samples

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come from the Pilbara drilling project

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drill core 2 which have penetrated the

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dresser bedded church had depth of about

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80 to 90 meters below a section of

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padova sods providing relatively fresh

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samples to work with our samples come

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mostly from the bedded church at the

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upper part of the core but also from a

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hydrothermal trade vein at the bottom

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part of the core and so samples were cut

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into thin sections and studied under

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reflected and transmitted light before

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the analysis so here you see a clean

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section of bedded shirt from the

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uppermost part of the section I which

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yielded the most diverse assemblage of

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organic micro structures and we have

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identified five main types of organic

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micro structures in the samples there's

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of dispersed organic matter amorphous

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organic matter clot that occur in this

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rich organic matter each beds and these

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were designated type 1 plot and there

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was another type of clots which had a

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more distinct shape and occur mostly in

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the organic matter for beds and these

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were designated type to clot and except

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for those we have also find organic

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matter which was concentrated along

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state oolitic front and organic matter

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that is preserved in the core of

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carbonate so here are the results of our

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carbon in situ isotopic analysis over on

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the right sorry you see images of

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individual analysis pits in selected

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micro structures and the isotopic

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composition that was obtained for this

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specific pit and overall that you see

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that the the over

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range of isotopic composition in this

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sample is over 13 per meal over on the

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left you see histograms which present

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the distribution of isotopic composition

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in specific armed organic micro

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structures and the most interesting

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observation here is the bimodal

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distribution of organic of isotopic

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composition in in the clods between the

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type 1 plot which had an average

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isotopic composition of minus 28 per

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meal and type 2 clouds which have I

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average edges of the composition of

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minus 34 / mill here you see individual

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analysis isotopic composition that 13 C

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values plotted against on the 13 c h /

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13 c ratio which was also measured

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during the analysis in this ratio served

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as a proxy for the samples hydrogen

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carbon ratio so there is no correlation

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seen between these two parameters which

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is which is important for two reasons

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first of all it indicates that the range

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of isotopic composition that we see is

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not the result of a variable instrument

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bias that might arise from varying

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hydrogen content in the samples and

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second during thermal maturation of

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organic matter it can change isotopic

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composition by preferential loss of

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isotopically like methane and this this

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process usually leads to a negative

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correlation between isotopic composition

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and hydrogen carbon ratio which is not

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seen in the samples and therefore we

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interpret that the range of isotopic

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composition seen in the sample is a is

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an original heterogeneity another result

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of later thermal adoration here is the

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sample from a hydrothermal shirt vein

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and in this sample the only organic

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micro structure that we have identified

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is these are organic matter clots

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similar in appearance to the type 1

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clots which have I have shown in the bed

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at two example and isotopic composition

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in these clots are also similar to the

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idea topic composition of the type 1

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clots in the previous in the bed example

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with an average of about minus 28 per

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mil so this chick textural and isotopic

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similarity suggest that the clots both

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in the bed church and in the

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hydrothermal truth then have the same

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origin so what is the origin of this

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organic matter so as I said before some

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works have suggested that the organic

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matter could have formed by a biotic

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processes similar to the industrial

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fischer-tropsch synthesis in this

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process inorganic carbon mostly in the

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form of carbon monoxide or carbon

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dioxide is reduced by hydrogen over the

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surface of a metal catalyst and this

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process can form simple chains of

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hydrocarbon however the correlation that

187
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i have seen between isotopic composition

188
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and specific micro check stereotypes is

189
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hard to reconcile with this process if

190
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the source of organic matter was just

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simple polymerization of hydrocarbons

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formed this way we would have expected

193
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it to have a uniform as a topic

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composition at least in one single

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samples with in one sample which is not

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the case and likewise there are no

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evidence for extensive serpentine

198
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ization in the underlying puzzles which

199
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could have served as a source of

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hydrogen needed for the reaction over

201
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the occurrence of suitable

202
00:11:02,769 --> 00:10:59,209
metal-catalyzed catalyst in the dresser

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choot and how it does i did i reconcile

204
00:11:08,229 --> 00:11:05,359
with a biogenic origin in some of the

205
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sample studies we have also measured

206
00:11:13,860 --> 00:11:10,970
years to be composition of anchor I

207
00:11:16,929 --> 00:11:13,870
Bernard Rome's and we have found that

208
00:11:19,269 --> 00:11:16,939
the isotopic on Carter fractionation

209
00:11:21,579 --> 00:11:19,279
between anchorite which is the inorganic

210
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carbon and organic matter is in the

211
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range of twenty five to thirty three per

212
00:11:34,269 --> 00:11:28,600
mil and this range is consistent with

213
00:11:36,639 --> 00:11:34,279
carbon fixation both by autotrophic

214
00:11:39,280 --> 00:11:36,649
organisms using the reductive acetyl-coa

215
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pathways which are mostly Kim autotrophs

216
00:11:46,569 --> 00:11:43,100
and organisms that utilize the calvin

217
00:11:49,059 --> 00:11:46,579
cycle so our data cannot distinguish

218
00:11:53,369 --> 00:11:49,069
between these two carbon fixation path

219
00:11:58,240 --> 00:11:53,379
but it is generally consistent with

220
00:12:02,470 --> 00:11:58,250
autotrophic microbial carbon fixation so

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just a quick conclusion so we have shown

222
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that in situ carbon isotopic analysis in

223
00:12:09,910 --> 00:12:08,240
a destitute reveal submicron

224
00:12:13,119 --> 00:12:09,920
heterogeneities which correlate to

225
00:12:16,299 --> 00:12:13,129
specific micro structural types and the

226
00:12:19,660 --> 00:12:16,309
range of values is thought to represent

227
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the original primary organic matter as a

228
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topic heterogeneity and the correlation

229
00:12:27,790 --> 00:12:26,029
between isotopic composition and

230
00:12:30,759 --> 00:12:27,800
specific microstructure type is hard to

231
00:12:33,280 --> 00:12:30,769
reconcile with solely a biotic origin

232
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for the organic matter and the

233
00:12:36,869 --> 00:12:35,449
fractionation between inorganic and

234
00:12:39,280 --> 00:12:36,879
organic carbon in the sample is

235
00:12:42,429 --> 00:12:39,290
consistent with somatic carbon fixation

236
00:12:45,699 --> 00:12:42,439
both by photo edit row' and chemo dito

237
00:12:49,869 --> 00:12:45,709
electrical and I will finish with this

238
00:12:52,540 --> 00:12:49,879
artist impression of early life and I

239
00:12:54,340 --> 00:12:52,550
think it's nice can nicely fit the

240
00:12:58,240 --> 00:12:54,350
environment represented dresser

241
00:13:00,009 --> 00:12:58,250
formation which could have both photo

242
00:13:03,460 --> 00:13:00,019
autotrophs represented by stromatolite

243
00:13:07,530 --> 00:13:03,470
and kim water troughs which could have

244
00:13:13,920 --> 00:13:07,540
thrived in the hydrothermal environment

245
00:13:28,150 --> 00:13:24,190
huh thank you very much for a

246
00:13:29,949 --> 00:13:28,160
presentation I so you have a schematic

247
00:13:33,699 --> 00:13:29,959
view for the formation of the

248
00:13:37,300 --> 00:13:33,709
hydrocarbon species on the surface I

249
00:13:40,150 --> 00:13:37,310
just learned because you have carbon

250
00:13:44,139 --> 00:13:40,160
monoxide and also oxygen on the surface

251
00:13:49,060 --> 00:13:44,149
it will be that form most stable like a

252
00:13:50,410 --> 00:13:49,070
carbon dioxide species home you're

253
00:13:53,199 --> 00:13:50,420
talking about the carbon monoxide which

254
00:13:55,949 --> 00:13:53,209
is shown for the fish for the future

255
00:13:59,100 --> 00:13:55,959
dropped accent is it well industrial

256
00:14:02,380 --> 00:13:59,110
fischer-tropsch synthesis utilize arm

257
00:14:04,360 --> 00:14:02,390
carbon monoxide mostly but this process

258
00:14:09,550 --> 00:14:04,370
was also suggested that could happen

259
00:14:12,759 --> 00:14:09,560
with carbon dioxide so the the

260
00:14:14,620 --> 00:14:12,769
hydrothermal system the dresser probably

261
00:14:19,480 --> 00:14:14,630
had a lot of carbon dioxide I don't know

262
00:14:24,010 --> 00:14:19,490
if it had carbon monoxide you know this

263
00:14:26,920 --> 00:14:24,020
is just as a possibility of a biotic of

264
00:14:29,650 --> 00:14:26,930
information and by the fischer-tropsch

265
00:14:34,660 --> 00:14:29,660
synthesis it's just a suggestion I mean

266
00:14:36,579 --> 00:14:34,670
oh come and it was suggested that it can

267
00:14:41,079 --> 00:14:36,589
also utilize carbon dioxide it just

268
00:14:42,040 --> 00:14:41,089
shown it as an example I don't really

269
00:14:50,220 --> 00:14:42,050
think that this process actually