# Use of trace elements to distinguish flows from different types of carbonated rocks

Leïla Serène, Christelle Batiot-Guilhe, Naomi Mazzilli, Philippe Leonide, Christophe Emblanch, Eléonore Resongles, Rémi Freydier, Léa Causse, Milanka Babic, Julien Dupont, et al.

<figure><img src="image_1.png" /></figure>

## ► To cite this version:

Leïla Serène, Christelle Batiot-Guilhe, Naomi Mazzilli, Philippe Leonide, Christophe Emblanch, et al. Use of trace elements to distinguish flows from different types of carbonated rocks. IAHS-AISH Scientific Assembly 2022, May 2022, Montpellier, France. pp.1-22, 10.5194/iahs2022-329. hal-03817369

HAL Id: hal-03817369

https://hal.science/hal-03817369

Submitted on 17 Oct 2022

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# Use of trace elements to distinguish flows from different types of carbonated rocks

Leïla Serène¹, Christelle Batiot-Guilhe¹, Naomi Mazzilli², Philippe Léonide³, Christophe Emblanch², Eléonore Resongles¹, Rémi Freydier¹, Léa Causse⁴, Milanka Babic², Julien Dupont², Roland Simler², Matthieu Blanc, Gérard Massonnat⁵

1. HydroSciences Montpellier (HSM), Univ Montpellier, CNRS, IRD, Montpellier, France

2. UMR 1114 EMMAH (AU-INRAE), Université d'Avignon, 84000 Avignon, France

3. Aix Marseille Univ, CNRS, IRD, INRAE, CEREGE, Aix-en-Provence, France

4. OREME, Univ Montpellier, CNRS, INRAE, IRD, Montpellier, France

5. TotalEnergies, CSTJF, Avenue Larribau, CEDEX 64018 Pau, France
# Karst : a valuable but complex water resource

## Karst water resource (Stevanović, 2019)

- 9.2% of the world's drinking water

- 13% of the total global withdrawal of groundwater

## Karst specificities

- Heterogeneous and compartmentalized systems

- Dual flows (fast/slow)

- Vulnerability associated to fast flow

<figure><img src="image_3.png" /></figure>
# Karst : a valuable but complex water resource

## Karst water resource (Stevanović, 2019)

* 9.2% of the world's drinking water

* 13% of the total global withdrawal of groundwater

## Karst specificities

* Heterogeneous and compartmentalized systems

* Dual flows (fast/slow)

* Vulnerability associated to fast flow

<figure><img src="image_4.png" /></figure>

Why is karst such a complex media?
# From carbonated platform to karst aquifer

<figure><img src="image_5.png" /></figure>

Carbonates
deposition

Variability of carbonate
sediments
# From carbonated platform to karst aquifer

<figure><img src="image_6.png" /></figure>

Variability of carbonate sediments

Diagenetic variability
# From carbonated platform to karst aquifer

<figure><img src="image_7.png" /></figure>

Variability of carbonate sediments

Diagenetic variability

Hydrodynamic and hydrochemical variability of flows in unsaturated zone
# Aim of the study

<figure><img src="image_8.png" /></figure>

## Path taken by water

### Drain

Fast transit

<figure><img src="image_9.png" /></figure>

Short water rock interaction time

<figure><img src="image_10.png" /></figure>

No or little rock signature

### Matrix

Low transit

<figure><img src="image_11.png" /></figure>

Longer water rock interaction time

<figure><img src="image_12.png" /></figure>

Rock signature
# Aim of the study

<figure><img src="image_13.png" /></figure>

① Facies 1 signature

② Facies 1 signature

③ Mix of facies 1 & 2 signatures

## Path taken by water

### Drain

Fast transit

<figure><img src="image_14.png" /></figure>

Short water rock
interaction time

<figure><img src="image_15.png" /></figure>

No or little rock
signature

### Matrix

Low transit

<figure><img src="image_16.png" /></figure>

Longer water rock
interaction time

<figure><img src="image_17.png" /></figure>

Rock signature
# Aim of the study

<figure><img src="image_18.png" /></figure>

① Facies 1 signature

② Facies 1 signature

③ Mix of facies 1 & 2 signatures

## Path taken by water

### Drain

Fast transit

<figure><img src="image_19.png" /></figure>

Short water rock interaction time

<figure><img src="image_20.png" /></figure>

No or little rock signature

### Matrix

Low transit

<figure><img src="image_21.png" /></figure>

Longer water rock interaction time

<figure><img src="image_22.png" /></figure>

Rock signature

Can trace elements be used as a natural tracer of path taken by water into karst systems?

→ Trace elements variations in karst rocks?
# Study site & sampling

<figure><img src="image_23.png" /></figure>

## Fontaine de Vaucluse karstic system

* Catchment of 1160 km² Ollivier, 2020

* Aquifer thickness up to 1500m

* Unsaturated zone average thickness 800m

## Rock sampling

* 108 limestone samples
  → Representatives facies (several replicates)
# Rock analysis

<figure><img src="image_24.png" /></figure>

## How to get a trace signal in the rocks that will be comparable to the signal in the water?

### Water-rock interaction

* Fast reacting system = short storage duration (few years max)

→ Not enough time to dissolve silicates (thousands of years Shand et al., 2007)

→ Clays have large water-rock interaction surface

→ Major impact of carbonate dissolution
# Rock analysis

<figure><img src="image_25.png" /></figure>

## How to get a trace signal in the rocks that will be comparable to the signal in the water?

### Water-rock interaction

* Fast reacting system = short storage duration (few years max)

→ Not enough time to dissolve silicates (thousands of years Shand et al., 2007)

→ Clays have large water-rock interaction surface

→ Major impact of carbonate dissolution

### Trace elements in rocks

* Carbonate has low trace element content in comparison with silicates (Shand et al., 2007)

→ carbonate signal may be hidden by the silicate one

→ Necessary to analyse only the carbonated matrix of our samples
# Rock analysis

<figure><img src="image_26.png" /></figure>

## How to get a trace signal in the rocks that will be comparable to the signal in the water?

### Analytic method development

* Use of hydrochloric acid 0.15 M to avoid silicates dissolution (molarity < 0.18 M Bastian et al., 2018)

→ Carbonated fraction of all samples analysed for all Mendeleïev tab by ICP-MS
# Rock analysis

<figure><img src="image_27.png" /></figure>

## How to get a trace signal in the rocks that will be comparable to the signal in the water?

### Analytic method development

* Use of hydrochloric acid 0.15 M to avoid silicates dissolution (molarity < 0.18 M Bastian et al., 2018)

→ Carbonated fraction of all samples analysed for all Mendeleïev tab by ICP-MS

### Results validation and pre-treatment

* Total analysis of all samples performed by ICP-OES

→ Check that all the carbonated fraction was considered by ICP-MS
# Clustering of rock samples

Hierarchical clustering with 16 trace elements :
Li, B, S, V, Cr, Co, Ni, Cu, Zn, As, Rb, Sr, Cd, Ba, Pb, U

<figure><img src="image_28.png" /></figure>
# Clustering of rock samples

Hierarchical clustering with 16 trace elements :
Li, B, S, V, Cr, Co, Ni, Cu, Zn, As, Rb, Sr, Cd, Ba, Pb, U

<figure><img src="image_29.png" /></figure>
# Clustering of rock samples

Clear link between clustering and deposit environments

→ This signal may be transmitted to karst water

<figure><img src="image_30.png" /></figure>
Conclusions & perspectives

Karst rock

Development of a
suitable rock analysis
method

<figure><img src="image_31.png" /></figure>

Clustering analysis:
classification according
to deposit environments

<figure><img src="image_32.png" /></figure>

Trace elements
signatures of deposit
environment in the
carbonated matrix
# Conclusions & perspectives

## Karst rock

Development of a
suitable rock analysis
method

<figure><img src="image_33.png" /></figure>

Clustering analysis:
classification according
to deposit environments

<figure><img src="image_34.png" /></figure>

Trace elements
signatures of deposit
environment in the
carbonated matrix

## Karst water

One year bi-monthly
sampling of 4 springs,
1 loss and 10 UZ flows

<figure><img src="image_35.png" /></figure>

Characterization of trace
fingerprints in water :
Work in progress

<figure><img src="image_36.png" /></figure>

Trace elements
signatures in waters
Conclusions & perspectives

<figure><img src="image_37.png" /></figure>
# Use of trace elements to distinguish flows from different types of carbonated rocks

<figure><img src="image_38.png" /></figure>

Can trace elements be used as a natural tracer the path taken by water in karst systems?

Leïla Serène, Christelle Batiot-Guilhe, Naomi Mazzilli, Philippe Léonide, Christophe Emblanch, Eléonore Resongles, Rémi Freydier, Léa Causse, Milanka Babic, Julien Dupont, Roland Simler, Matthieu Blanc, Gérard Massonnat

1. Facies 1 signature

2. Facies 1 signature

3. Mix of facies 1 & 2 signatures
Analytic method

Partial analysis protocole

1/ Weigh 50 mg of sample

2/ 10 mL of 0.15 M HCl

3/ Shake for 19 h at 300 rpm

4/ Filtration at 0.22 µm

5/ Evaporate at 70°C - lasts 2-3 days

6/ Add 15mL of HNO₃ 10%, weigh

7/ Ultrasound 15min

8/ Dilute 1mL in ICP-Ms tubes, complete
with water

9/ ICP-MS

Partial analysis

$$
\text{ICP-MS} = \begin{array}{@{}l@{}} \text{Inductively coupled plasma} \\ \quad \text{mass spectrometry} \\ \quad \rightarrow \text{lower detection limits} \end{array}
$$

Total analysis

$$
\text{ICP-OES} = \begin{array}{@{}l@{}} \text{Inductively coupled plasma} \\ \quad \text{optical emission spectrometry} \end{array}
$$