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Table 2 Lithostratigraphic column for the Geneva Basin and geological tunnelling hazards linked to different lithotypes potentially relevant for FCC construction

From: Integrated stratigraphic, sedimentological and petrographical evaluation for CERN’s Future Circular Collider subsurface infrastructure (Geneva Basin, Switzerland-France)

Period

Epoch

Stage

Rock types

Lithostratigraphic notations

lithostratigraphy (this study)

lithotypes

(this study)

abbreviation of lithotypes (see Fig. 4)

FCC’s geological hazards

(this study)

Quaternary

 

Holocene

Absent

Absent

Topsoil

Topsoil

Topsoil

 

Pleistocene

Late

Silty-Clayey Gravel, Conglomerate

Glaciogenic deposits, LGM moraines

Post-glacial sediments, LGM moraines

Clayey to (sometimes) sandy gravel mixtures, clast with grey-beige plastic consistency

A3

Active faults

Cemented & unconsolidated, interglacial sediments

dark grey, clayey mud- and wackestone with pollen traces

A2

Water-bearing aquifers

Middle

Pre-glacial sediments

Mixture of fine sand and sandstone embedded in clayey matrix

A1

Water-bearing aquifers

Paleogene

Oligocene

Serravalian

Conglomerate

Upper Freshwater Molasse (UFM)

Absent

Absent

Absent

Absent

Langhian

Sandstone, marl

Upper Marine Molasse (UMM)

Absent

Absent

Absent

Absent

Burdigalian

Sandstone

Absent

Absent

Absent

Swelling clays, anhydrite (AG), hydrocarbons (HC), active faults

Aquitanian

Molasse Grise

Lower Freshwater Molasse (LFM), (Molasse Rouge*, Grès et Marnes Gris à gypse*)

Absent

Absent

Absent

Swelling clays, anhydrite (AG), hydrocarbons (HC), active faults

Chattian

Grès et Marnes Gris à gypse, Molasse Rouge (upper and lower succession)

Grès et Marnes Gris à gypse, Molasse Rouge as part of LFM

Upper succession: sandstone with intercalations of marly siltstone

lower succession: clayey limestone, breccia, sandstone, alternating thin beds of very fine to fine sandstone, laminated clayey siltstone

Anhydrite/gypsum layers

Hydrocarbon-bearing sandstone. Limestone

S1, S2, S3, S4, S5; M1, M2, M3, M4, M5; AG; HC; L

Swelling clays, anhydrite (AG), hydrocarbons (HC), active faults

Rupelian

Sandstone, conglomerate

Lower Marine Molasse (LMM)

 

Conglomerate(?), part of Siderolithic(?)

C1, C2

Swelling clays, anhydrite (AG), hydrocarbons (HC), active faults

Eocene

 

Sandstone

Siderolithic

Siderolithic

Conglomerate with quartz and limestone in clayey cement

C1, C2, S6, G1

Karst, hydrocarbons, active faults

Transition zone (Perte-du-Rhône Formation?)**

Transition zone

Not stratified, karstic sandstone alternations(?)

KS

Karst, hydrocarbons, active faults

Cretaceous

Early

Barremian

Limestone, often marly

Vallorbe Member of the Rocher des Hirondelles Formation and Gorges de l’Orbe Formation (both formerly represented by the Urgonien)

Vallorbe Member of the Rocher des Hirondelles Formation

Massive limestone

ML

Karst, hydrocarbons, active faults

Hauterivian

Marly to silty limestone

Vallorbe Member of the Rocher des Hirondelles Formation and Gorges de l’Orbe Formation (both formerly represented by the Urgonien), Grand Essert Formation (Hauterive Member and Neuchâtel Member)

Vallorbe Member of the Rocher des Hirondelles Formation, Grand Essert Formation (Hauterive Member and Neuchâtel Member)

Marly-sandy limestone, sometimes dolomitic, mud- /wackestone; limestone with siltstone

MSLd, MLs

Karst, hydrocarbons, active faults

Valanginian

Marl and sandstone alternations with intercalations of limestone

Grand Essert Formation (Hauterive Member), Vuache Formation

Grand Essert Formation (Hauterive Member), Vuache Formation

Marly-sandy limestone, sometimes dolomitic

MSLd

Karst, hydrocarbons, active faults

Berriasian

Limestone

Goldberg Formation, Chambotte Formation, Pierre-Châtel Formation, Vions Formation, Neuchâtel Member

Goldberg Formation, Chambotte Formation, Pierre-Châtel Formation, Vions Formation, Neuchâtel Member

Massive limestone; marly-sandy limestone, biomicrite and wacke-/packestone

ML, MSL

Karst, hydrocarbons, active faults

Jurassic

Late

Tithonian

Twannbach Formation

Twannbach Formation

Massive, dolomitic, partly fine-grained limestone; dolomitic limestone, massive dolomite

L, Ld, MD

Karst, hydrocarbons, active faults

Kimmeridgian

Twannbach Formation, Etiollets Formation (Tabalcon sub-unit), Blanc Limestone

Twannbach Formation, Etiollets Formation (Tabalcon sub-unit), Blanc Limestone

Dolomitic, clayey limestone, sometimes massive limestone

DCL, ML

Karst, hydrocarbons, active faults

Oxfordian

Balsthal Formation, Vellerat Formation***

Balsthal Formation, Vellerat Formation***

Clayey to marly limestone and marlstone

CML, M1

 
  1. Bold area refers to the geology encountered by the FCC in its current subsurface layout. Rock types and lithostratigraphic notations after Blondel, 1984; Brentini, 2018; Burkhard & Sommaruga, 1998; Charollais et al., 2007; Deville et al., 1994; Graf & Burkhalter, 2016; Jaquet, 1966; Kissling, 1974; Moscariello, 2019; Strasser et al., 2016
  2. *Molasse Rouge and Grès et Marnes Gris à gypse are commonly referred to informal but valid names as part of the LFM. **Currently under discussion but might imply new insights on the Mesozoic-Cenozoic boundary(?) as part of imminent research results for the GB. ***Currently under discussion, not yet fully defined. LGM Last Glacial Maximum