An overview of the definition and history of the Virtonian is given with the argumentation for the abandonment of this disused regional stage

Boulvain, F.

Delsate, D.

peer reviewedAn overview of the definition and history of the Virtonian is given with the argumentation for the abandonment of this disused regional stage

Boulvain, Frédéric

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Disused Jurassic regional stage from Belgium: Virtonian

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GEOLOGICA BELGICA (2006) 9/1-2: 199-200
DISUSED JURASSIC REGIONAL STAGE FROM BELGIUM: VIRTONIAN
Dominique DELSATE1 & Frédéric BOULVAIN2
1.  Laboratoire de Paléontologie-Géologie, C.R.S. du Musée national d’Histoire naturelle de Luxembourg, 25, rue Münster, 
L-2160 Luxembourg.
2.  Géologie-Pétrologie-Géochimie, B20, Université de Liège, Sart Tilman, 4000-Liège, Belgium; E-mail: FBoulvain@ulg.ac.be
ABSTRACT. An overview of the deﬁ nition and history of the Virtonian is given with the argumentation for the 
abandonment of this disused regional stage.
KEYWORDS: Virtonian, Belgium, Jurassic.
Reference to this paper: Delsate, D & Boulvain, F., 2006. Disused Jurassic regional stage from Belgium: Virtonian. 
In Dejonghe, L., ed., Current status of chronostratigraphic units named from Belgium and adjacent areas, Geologica 
Belgica, Brussels, 9/1-2: 199-200.
1. Defi nition and history
Dumont (1842) uses the term “Sables, schistes et macigno 
d’Aubange” for the units called “Virtonien” by later au-
thors, while Dewalque (1857) employs “Sables et Grès 
de Virton, Schiste d’Ethe, Macigno d’Aubange”. Purves 
(1884a) (p.3, 19), uses the term “étage Virtonien” (Vr) 
for the Middle Lias, synonymous with Dumont’s (1842) 
Sables, schistes et macigno d’Aubange. Purves divided the 
Virtonian stage into:
-  Assise de Virton, Vr1, synonymous with the Sable 
d’Aubange of Dumont (1842); 
-  Grès de Virton (Dewalque, 1857), equivalent to the 
Planicosta Zone of French and German authors;
-  Assise d’Ethe, Vr2, synonymous with the Schiste 
d’Aubange of Dumont (1842), Schiste d’Ethe of 
Dewalque (1857), Marnes à ovoïdes and the Zone of 
Belemnites clavatus of the French authors;
-  Assise d’Aubange, Vr3, synonymous with the Macigno 
d’Aubange of Dumont (1842).
Purves (1884b, 1884c, 1885) conﬁ rms the use of the 
“Etage Virtonien”, characterised by Ostrea cymbium. 
DORMAL uses the term Virtonien (Dormal 1894 : 112, 
117, 128), for the sand-dominated facies of the Grès de 
Virton West of Arlon, together with the marly intercala-
tions containing Spiriferina münsterii, Pecten disciformis, 
Gryphaea cymbium, Asteroceras obtusum, and the marly 
facies (Marne de Hondelange) at Autelbas, preserving 
Gryphaea cymbium, Eoderoceras armatum and Promicroceras 
planicosta. He divided the Virtonian stage into:
-  Vr4 : Macigno d’Aubange : A. spinatus ; 
-  Vr3 : Macigno de Messancy : A. margaritatus ; 
-  Vr2 : Schiste et marne d’Ethe : A. davoei ; 
-  Vr1s : Grès de Virton ; Vr1m : Marne de Hondelange : 
A. armatus, A. planicosta, A. oxynotus, A. obtusus.
On the 1:40 000 geological map of Belgium produced 
by Dormal (1897) the Virtonian stage is subdivided into 
4 units:
-  Vrd: Macigno ferrugineux d’Aubange., with Pleuroceras 
spinatum;
-  Vrc : Macigno, schistes et psammites de Messancy, 
with Amaltheus margaritatus;
-  Vrb : Schiste d’Ethe with Lytoceras davoei;
-  Vras : Sables et grès de Virton;
-  Vram : Marne sableuse de Hondelange with Deroceras 
armatus, Oxynoticeras oxynotum, Aegoceras planicosta, 
Arietites obtusum and Caenisites turneri
Jérôme (1910a & 1910b), uses the term “Virtonien” with 
the following subdivisions:
-  Vrb : Schiste d’Ethe à Deroceras davoei;
-  Vra s : Sable et grès de Virton, with Vra si, Virtonien 
sableux inférieur, Vra ss, Virtonien sableux supérieur;
-  Vra m : Marne sableuse de Hondelange, with Vra ms, 
Marnes de Hondelange supérieures, - Vra mm, Marnes 
de Hondelange moyennes, and Vra mi, Marnes de 
Hondelange inférieures.
2. Why the Virtonian is not an international 
stage
S e Virtonian was deﬁ ned as a stage by Purves (1884a), 
and conﬁ rmed by Dormal (1894) following a ﬁ eld excur-
200 DOMINIQUE DELSATE & FRÉDÉRIC BOULVAIN
sion organized by the Société géologique de Belgique. As 
originally deﬁ ned, the Virtonian encompassed a large bi-
ostratigraphic interval, including very diﬀ erent lithologi-
cal units, many of which are diﬃ  cult to date. Important 
lateral facies variations and complex interdigitations have 
led to a great deal of confusion over the use of the term.
3. Status of the name
S e term « Virtonian » is best avoided because it is a 
transitional stage between the shale-dominated Toarcian 
and the sand-dominated Sinemurian. Its lower boundary 
is diﬃ  cult to deﬁ ne, but must lie at an as yet unspeciﬁ ed 
level in the Grès de Luxembourg. S e old Vra to Vrd 
units extend from the current Membre de Virton to the 
Formation d’Aubange (Sinemurian to Pliensbachian) 
(Boulvain et al., 2001).
References
BOULVAIN, F., BELANGER, I., DELSATE, D., 
GHYSEL, P., GODEFROIT, P., LALOUX, M., 
MONTEYNE, R. & ROCHE, M., 2001. Triassic and 
Jurassic lithostratigraphic units (Belgian Lorraine). In 
Bultynck, P. & Dejonghe, L., (eds.), Guide to a revised 
lithostratigraphic scale of Belgium. Geologica Belgica, 
4(1-2), 113-119.
DEWALQUE, G., 1857. Description du Lias de la Prov-
ince de Luxembourg. Dissertation inaugurale. Mémoire 
in-8°, 1-65. Liège.
DORMAL, V., 1894. Compte-rendu de l’excursion de la 
Société belge de Géologie dans les terrains jurassique et 
triasique des environs d’Arlon et de Florenville. Bulletin 
de la Société belge de Géologie, de Paléontologie et d’Hydro-
logie, 8: 102-129.
DORMAL, V., 1897. Meix-devant-Virton - Virton, carte 
géologique de la Belgique à l ’échelle 1/40000. Institut Car-
tographique Militaire, Bruxelles.
DUMONT, A., 1842. Mémoire sur les terrains triasiques 
et jurassiques dans la Province de Luxembourg. Nouveaux 
Mémoires de l ’Académie Royale de Bruxelles, 15: XXX p.
JEROME, A, 1910a. Texte explicatif du levé géologique 
de la Planchette d’Arlon. Service géologique de Belgique, 
219: 1-23.
JEROME, A., 1910b. Texte explicatif du levé géologique 
de la Planchette de Habay-la-Neuve. Service géologique 
de Belgique, 219: 1-24.
PURVES, J.-C., 1884a. Explication de la Feuille de Vir-
ton. Musée royal d’Histoire naturelle de Belgique. Service 
de la carte géologique du Royaume.
PURVES, J.-C., 1884b. Explication de la Feuille de Ru-
ette. Musée royal d’Histoire naturelle de Belgique, Service 
de la carte géologique du Royaume, 1-30.
PURVES, J.-C., 1884c. Explication de la Feuille de 
Lamorteau. Musée royal d’Histoire naturelle de Belgique, 
Service de la carte géologique du Royaume, 1-32.
PURVES, J.-C., 1885. Explication de la Feuille de Meix-
devant-Virton. Musée royal d’Histoire naturelle de Belgi-
que, Service de la carte géologique du Royaume, 1-25.
Manuscript received on 26.10.2004 and accepted for 
publication on 03.05.2005.


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Disused Jurassic regional stage from Belgium: Virtonian

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