YOUNG PROFESSIONAL
tools that allow us to elucidate the temperature of carbonate caprock formation and thereby check if thermochemical sul- fate reduction was responsible for the genesis of native sulfur associated with the carbonate, testing the microbial option is a daunting task: detecting an unknown, hidden process is like chasing down a ghost. What would help in this endeavor is to know a reason why microbes might make native sulfur. I think that too much sulfide is just too stinky for them: at high concentrations, sulfide is toxic to organisms. Thus, if one puts hydrocarbons and sulfate-reducing bacteria into one box, they might produce sulfide, but only up to the point where sulfide accumulation would kill them. Under such circumstances, it would be beneficial for the sulfate-reducing bacteria to switch from the production of toxic sulfide to harmless native sulfur.
This closed-box scenario is the direct opposite of the gener- ally accepted model for native sulfur formation where there
Sulfur crystals
While this scenario is possible, one must ask: is there not an easier explanation? Which is exactly the question I aim to answer with my Ph.D. research.
Alternatives to the genesis of native sulfur by oxidation of sulfide with an oxidant (such as oxygen or nitrate) would be oxidation of sulfide with the help of light, thermochemical sulfate reduction or a ‘direct’ formation of native sulfur by microbes without the help of an external oxidant. The first option is not possible for carbonate caprock formation because this happens underground in the absence of light. On the other hand, generating native sulfur through abiotic thermochemi- cal sulfate reduction at elevated temperatures is a possibility, whereas the microbial option is thermodynamically possible but has never been observed. While there are geochemical
Book Release The Art of Water Wells by Marvin F. Glotfelty, RG
The book is a comprehensive overview of well systems ideal for everyone working in the groundwater field.
It provides practical information of water wells—covering every- thing from site selection to design, drilling methods, economics, and more—and is written in a fashion that is understandable, technically accurate, and applicable to real-world situations.
At more than 170 pages and featuring numerous drawings, photos, tables, and appendices, it is designed to be a valuable resource for well designers, contractors, engineers, water managers, and hydrogeologists.
2019 / 173 pages Catalog #T1116
https://my.ngwa.org/NC__Product?id=a1838000012aPlyAAE Image source: National Ground Water Association
is a need for ample supply with O2. The system in which native sulfur is formed requires in one case very restricted fluid exchange to ensure build-up of sulfide to toxic levels, whereas it requires in the other case ample fluid exchange
to ensure supply with O2. With this, the daunting task has become much less intimidating: as for the determination of the formation temperature of carbonate rocks, there are also geochemical tools that can be used to assess if these rocks, and the native sulfur, formed under restricted or ample fluid supply. Moreover, having a hypothesis for when the microbes switch from stinky sulfide to native sulfur production also provides me with ideas how to trick them into doing this in laboratory incubation experiments.
These concepts guide me in my Ph.D. research, from the bramble and biting insects-infested Damon mound salt diapir near Houston, TX in March to icy field work at the salt diapirs in Colorado and Utah in November, and during the hours play- ing with stinky mud in the laboratory at UTEP. How amazing is it to be a geologist?!
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64
