Can i apply this methods in unraveling the history of the flank sediments of Mid ocean ridge.
Dear Dr. Olatunde,
The REE are certainly a good tool to get an idea of how sediments formed. But I cast very much doubt on those papers published by research workers only taking a chemical approach, using ,e.g., the Ce or Eu anomalies or interpreting a series of cross plots and the skewness of the REE tot. You can believe in them but there is no need to do so. There must be a bit more meet on the bone in form of mineralogy. It makes a difference whether you deal with detrital hosts of REE such as monazite and xenotime which are different as to the sensitivity to HREE and LREE or with ion-absorption to special clay minerals. A third party is the organo-mineralic bonding.
Moreover a critical issue is the environment of deposition. If these questions are left unanswered the "real" value of the study is restricted.
With best regards
H.G.Dill
Thanks professor Harald,meaning that X-ray diffraction and petrographic analysis are equally important.What methods can I use to address the organo-metallic bonding and the environment of deposition.Is biostratigraphic analysis an option?.t.Any recent publication that can equally assist?.
Dear Mr. Olatunde,
Because of the accessory nature of REE minerals and their complex bonding history, a simple XRD powder diagram will not lead to satisfactory results. Normally a detailed analysis involves a mineral separation prior to the analytical investigation which can be done by means of XRD, SEM-WDX/EDX combined with MLA or EMPA. It is difficult to create a flow-sheet how to process the sediments, because it depends on the lithology, the environment of deposition and the goal of your work.
Best regards
H.G.Dill
Dear Popoola
While I agree with the suggestions made by Dr. Dill; you may use chemical partitioning techniques to know about the association of organo-metallic bonds. For this purpose you may use Hydrogen Peroxide (30%w/v) on a water bath.
Truly yours
karbassi
Like any other data-set, REE has its own value. However, on a stand-alone basis, I would take REE data with a pinch of salt in deciphering sedimentation history.
REE data can provide (subject to certain key indicators already pointed out by Prof. Dill), a fair indication of the provenance and erosional process that brought in the detritus into the depositional system. However, they should be used as 'additional / supplementary' proof for inferences drawn from more basic observations of the sediments such as mineralogy, texture, etc. They may not be used as the primary evidence.
REE data has been used rather convincingly, based on statistically sound databases of secular changes in certain elements over time, to model meta-sedimentary rocks. But for primary (unmetamorphosed) sedimentary rocks, they should be used only as supporting / supplementary / corroborative data.
Minerals containing REE are 20:
Aeschynite, Allanite, Bastnasite, Betafite, Britholite, Brockite, Cerite, Euxenite, Fergusonite, Fluocerite, Gadolinite, Loparite, Monazite, Parisite, Samarskite, Stillwellite, Synchisite, Titanite, Xenotime and Zirconolite.
To have useful information on the basins providers of sediments, it necessary to define the exact mineralogy of the sediments, by means XRD. Generally the difficulty to obtain good information is related to dimensions of the River basin, the larger and more difficult is to figure out the origin of the sediments.
In the case of sediments it is necessary to separate the heavy sediments from the light, using chemists separators working on different specific gravities, or using mechanic concentrators, both gigs that spiral vertical concentrators, to obtain a good quantity of heavy minerals.
The Franz Machine operating on different magnetic susceptibility at 0,1 Ampere allow you to remove Minerals containing Iron (magnetite, ematite, ecc.), at 0,2 Ampere allow you to remove Titanium minerals (Ilmenite) and lastly at 0,3-0,6 Ampere allow you to remove Minerals containing RE. Diamagnetic heavy minerals will remain not separated. It is important to have a very good quantity of separated minerals because XRD give good answers when the concentration of the mineral to detect is more that 5% of the global mass.
Dear Popoola,
Maybe these papers will help you!
McLennan, S.M., 1989. Rare earth elements in sedimentary rocks; influence of provenance and sedimentary processes. Reviews in Mineralogy and Geochemistry 21, 169–200.
McLennan, S.M., Hemming, S., McDaniel, D.K., Hanson, G.N., 1993. Geochemical
approaches to sedimentation, provenance, and tectonics. Geological Society of
America Special Papers 284, 21–40.
Best regards
- Badges
- Science topic
- Similar topics
- Engineering
- Materials Engineering
- Powders