Drowning of a carbonate platform and reflection on adjacent basinal sedimentation: a Jurassic successions from the Julian Alps (NW Slovenia)

• Autorzy: Rozic B. , Smuc A.
• Konferencja: International Congress on the Jurassic System (7 ; 06-18.09.2006 ; Kraków, Poland)
• Języki publikacji: EN

Abstrakty

EN

The Julian Alps are located in northwestern Slovenia and extend to the west into northeastern Italy. Structurally they belong to the Julian and Tolmin Nappes that together form eastern continuation of the Southern Alps. In the Jurassic the investigated area was a part of the southern Tethyan passive continental margin and experienced extensional faulting due to the rifting. From the latest Triassic to Early Jurassic NW Slovenia belonged to the Julian Carbonate Platform bordered towards the south by deeper the Slovenian Basin. In the early Early Jurassic the platform was marked by sedimentation of tidal flat, lagoonal and ooidal limestone. Slovenian Basin was at that time characterized by abundant resedimented carbonates (Krikov Formation) shaded from marginal parts of the platform. In the Pliensbachian, shallow-water sedimentation on the Julian Carbonate Platform ended due to an extensional tectonic phase. At that time platform was dissected into blocks with different subsidence rates. Inner parts of the platform were probably emerged, while marginal parts were drowned and distal shelf limestone rich in sponge spicules and juvenile ammonites of Sedlo Formation deposited. The change of sedimentation style is also recorded in the Slovenian Basin, where resedimented carbonates of the Krikov Formation are abruptly overlain by marls, mudstones and siliceous limestone of the Perbla Formation. In the basin the pelagic sedimentation continued in Middle Jurassic, while on the area of the former Julian Carbonate Platform there is no sedimentary record from the Toarcian to the Bajocian. The accelerated subsidence in the Bajocian caused further deepening of the investigated area. In the basin this event corresponded to the sedimentation switch from shaly Perbla Formation to radiolarian cherts (radiolarites s.s.). Additionally the emerged area of the former Julian Platform was drowned and became a pelagic plateau named Julian High, with condensed sedimentation of ammonitico rosso type (Prehodavci Formation). Transitional zone forming the physical link between the plateau and the basin is characterized by onlap of radiolarites s.s. on the Pliensbachian Sedlo Formation. At the end of Jurassic the sea bottom morphology had became predominantly leveled as evidenced by monotonous sedimentation of the Biancone limestone.

Słowa kluczowe

EN

Jurassic; drowning; Julian Carbonate Platform; Slovenian Basin; transitional area

• Wydawca: Państwowy Instytut Geologiczny - Państwowy Instytut Badawczy
• Czasopismo: Volumina Jurassica
• Rocznik: 2006
• Tom: Vol. 4, no. 1
• Strony: 104--105

Twórcy

autor

Rozic B.

autor

Smuc A.

• University of Ljubljana, Faculty of Natural Sciences and Engineering, Geology Department, Privoz 11, 1000 Ljubljana, Slovenia,