Geology – Experimental facilities

Our analytical work partly relies on the analytical platform of the Center of Geosciences,  managed by the “Experimental Facilities” support team. Here are some equipment the team takes benefice from.

X -ray Diffraction analyses (XRD): X’Pert Pro (Philips)

Scientific manager: C. Franke

 

Geol_DRX

X’Pert Pro (Philips)

Geol-DRX02

X-ray diffraction analyses may be performed on:

  • – solid bulk rock samples (rocks, sediments, synthetic crystalline samples) to determine a (semi)quantification of the present mineral phases (quantification limit 5%,  detection limit 1%).
  • – the  “clay mineral” fraction to determine the detailed composition of the fine fraction (< 63 µm).

Applications:

Metallurgy, caracterization of mining or petrolium ressources, (paleo)climate and (paleo) environmental studies, valorization of (geo)materials, caracterization of anthropogenic anorganic phases in sediments, caracterization of mineral alterations, etc.

 Analytical protocol:

Bulk rock:
Samples are reduced to fine grained pouder (< 2 mm, 10-20 mg) and press in sample holders resulting in a non-oriented plane surface.

Clay mineral fraction:
The fine fraction is extracted using a combination of Atterberg and centrifugation approach.

 

Mass Spectrometer for isotopic analyses of carbonates (δ18O, δ13C) and water samples (δD, δ18O) : Isoprime 100 (Elementar)
Scientific managers: D. Huyghe (carbonates) / S. Guillon (water samples)


Geol_spectro

Isoprime 100 (Elementar)

 

 

Analytical  setup

 Instrumental setting: Isoprime 100 (Elementar) Dual Inlet

Our mass spectrometer may be employed either on carbonate (aragonite or calcite) or water samples.

These analyses are applied to different topics:

Carbonates:

  • Paleotemperatures reconstruction from the analysis of biomineralizations (mollusks, charophyte oogona, etc).
  • Characterization of the origin of secondary mineralizations linked to fluid circulations
  • Origin of detrital carbonates and source tracing.

Water samples:

  • Characterization of isotope lapse rates from river water in mountain ranges.
  • Deconvolution of  run off and ground water contributions during flood events.
  • Tracing sources of water at the catchment scale.
  • Tracing the infiltration in the unsaturated zone and quantification of groundwater recharge.
  • Quantification of hydrologic budget of lakes (evaporation).

Analytical protocol :

Rock samples:

100 to 200 µg of homogenized powder sample for pure carbonates
Extraction of CO2 at 90 °C
Reaction time with phosphorous acid: 3 minutes
Precision 0.05 ‰ for δ18O and 0.03 ‰ for δ13C.
Analyses e.g.  for Total, GET and the University of Perpignan

Water samples:

Volume: 200 µL of non-filtered water (may contain volatile compounds or dissolved salts). Equilibration with CO2(g) (resp. H2(g) with Pt catalyzer) during 7h (resp. 4h) at 40 °C.
Precision 0.08 ‰ for  δ18O and  1.0 ‰ for δD.

Participation in the GNIP network of isotope record of precipitations.
Participation in international  IAEA campaigns of laboratory comparisons and calibration: WICO 2016, WICO 2020.

 

X-ray fluorescence spectroscopy (XRF): portative XRF sensor (Olympus INNOV X Delta Premium,  commun instrument of the FIRE) and laboratory XRF sensor (Niton FXL)

Contact: C. Franke

 

XRF-portatif

portable XRF sensor Olympus INNOV X Delta Premium

laboratory XRF sensor Niton FXL

(analysable elements : Mg to  Bi)

The XRF analysis results in a (semi)quantification of the major element (%) and trace element (ppm) composition in rocks/minerals and synthetic anorganic materials.

The samples can be analyzed as dry bulk powder (some 10th gram) or a 2×2 cm solid sample with plane surface.

There are mutiple applications of the XRF technique, wich are complementary to the mineralogical DRX analysis:

Metallurgy, caracterization of mining or petrolium ressources. (paleo)climate and (paleo) environmental studies, valorization of (geo)materials, caracterization of anthropogenic anorganic phases in sediments, caracterization of mineral alterations, etc.

 

 

 

Differentiel GPS: Leica Zeno 20 Android

Contact: J.L.Grimaud

DGPS measurements allow realizing topographic surveys whose accuracy can be improved directly or using post processing by removing the ambient noise. The accuracy is generally of several decimeters and can go down to the centimeter depending on acquisition duration and satellite cover.

DGPS measurements are used for different purposes:

  • Measurement of bar morphology (including the shallow subaqeous part) in fluvial channels along transects
  • High resolution (cm) acquisition of water level in wetlands
  • Topographic profile measurement along valleys
  • Mapping of (geological) boundaries directly on the field
  • High resolution topographic maps acquisition

Measurement protocol :
Assembling of the antenna on the rod and connection to the receptor
30 to 90 s time acquisition for punctual measurement
Post processing using the ArcGIS software

 

Magnetism laboratory:  magnetic susceptibility meter (Bartington MS3) and Spinner magnetometer (AGICO-JR6)

Scientific manager: C. Franke

Geol_susceptMagnet

magnetic susceptibility meter (Bartington MS3)

MagnetometreJ6

Spinner magnetometer (AGICO-JR6)

 These instruments allow the analysis of the magnetic suscetibility of different solid samples, such as rocks, sediments, plants etc. in the laboratory and in the field. The analysis of the magnetic susceptibility is applied in the framework of (paleo)environmental studies (e.g. tracing of ferruginous minerals or metallic particles). The Spinner magnetometer serves to recover the natural remanent magnetisation (NRM) of oriented rock samples from palomagnetic studies.