Ivan Gušić

High-frequency sea-level changes recorded in deep-water carbonates of the Upper Cretaceous Dol Formation (island of Brač, Croatia)

High-frequency sea-level changes recorded in deep-water carbonates of the Upper Cretaceous Dol Formation (island of Brač, Croatia) The upper part of the Middle Coniacian/Santonian-Middle Campanian deep-water Dol Formation of the island of Brač is composed of countless fine-grained allodapic intercalations deposited in an intraplatform trough. Within the studied section 13 beds can be distinguished, each defined by its lower part built up of dark grey limestone with abundance of branched, horizontally to subhorizontally oriented burrows, and the upper part, in which the light grey to white limestone contains larger burrows, rarely branched, showing no preferential orientation. The lower, dark grey, intensively bioturbated levels are interpreted as intervals formed during high-frequency sea-level highstands, while the upper, light grey-to-white levels are interpreted as intervals formed during the high-frequency sea-level lowstands. Cyclic alternation of these two intervals within the fine-grained allodapic beds is interpreted as the interaction between the amount of carbonate production on the platform margin and the periodicity and intensity of shedding and deposition in the distal part of toe-of-slope environment, which is governed by Milankovitch-band high frequency sea-level changes.

Borehole MET-1/04 near Metlika, between the External and Internal Dinarides (SE Slovenia)

Raziskovalno-kaptažna vrtina MET-1/04 pri Božakovem, vzhodno od Metlike v Beli Krajini, je globoka 841 m. Namen vrtanja je bil zajeti geotermalno vodo, ki bi bila uporabljena v turisticne namene. Obmocje vrtine leži na prehodu zunajnih Dinaridov, ki so v splosnem zgrajeni iz mezozojskih plitvomorskih karbonatnih kamnin, v Notarnje Dinaride. Za slednje so znacilne predvsem globljemorske klasticne kamnine, ravno tako mezozojske starosti. Strukturna znacilnost obmocja je niz dinarsko usmerjenih narivov, ob katerih so Notarnji Dinaridi narinjeni na Zunanje. Sama vrtina je locirana v zgornjekredni flisni skladovnici, ki je odložena transgresijsko na zgornjejurske apnence. Flisno skladovnico do globine 182, 5 m sastevljajo breca, konglomerat ter kalkarenit in lapor. Navzdol do globine 275 m sledijo spodnjekredni apnenci, ki pripadajo ali velikim olistolitnim blokom v bazi flisa ali pa tektonskemu bloku v narivni luski. Do dna vrtine na 841 m nastopaju grebenski apneci zgornjejurske starosti. Zgornji del apnecev pripada zgornjemu malmu, spodnji del pa je mogoce že spodnjemalmske starosti. V vrtini sta bili ugotovljeni dve vodonosni coni in sicer v intervalu od 92.5 do 184 m ter v intervalu od 220 do 355 m.