Naslov
High Frequency Sea Level Change Recorded within non-cyclic Lower Aptian and cyclic Upper Aptian Platform-Interior Facies of the Adriatic Platform, Southern Croatia

Autori
Harman, Charles ; Sweeney, Rafferty, J. ; Husinec, Antun ; Read, J. Fred

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
AAPG Annual Convention & Exhibition, Abstracts Volume / - Denver (CO), 2009

Skup
American Association of Petroleum Geologists Annual Convention & Exhibition

Mjesto i datum
Denver (CO), Sjedinjene Američke Države, 07.06.2009. - 10.06.2009

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Adriatic Platform; Aptian; sea level; Croatia

Sažetak
This study explores Aptian aged platform-interior carbonate facies exposed on the Peljesac Penninsula and the islands of Korcula, Hvar, and Mljet in Southern Croatia. The Lower Aptian succession is characterized by non-cyclic, thick-bedded to massive subtidal facies of lime mudstone and skeletal-intraclastic lime mudstone and wackestone with rare benthic foraminifera, calcareous algae, microbial encrusters (Bacinella), bivalve fragments, as well as subordinate pelagic crinoids (Saccocoma) and planktic foraminifers (Hedbergella). The shallowest facies are skeletal-peloid wacke-packstones and grainstones with rudists ; these are calculated to occur in about 0-3 meters water depth. The cyclicity of the facies increases with proximity to the Early-Late Aptian boundary. The Upper Aptian is more cyclic, with parasequences consisting of basal skeletal mudstone-wackstone overlain by peloid-intraclast-skeletal packstone and grainstone, and barren mudstone, fenestral lime mudstone or microbial laminite. The emersion breccia horizons and/or residual clay horizons as parasequence caps are very common ; up to seven horizons are recorded in the lower, and six in the upper part of Upper Aptian.Maximum water depths of facies are estimated at 5 meters based on the range of stratigraphic distances of facies below base of laminate cap, breccias, or top of barren lime mudstone. The facies stacking patterns suggest an important environmental change during Aptian, with Early Aptian transgression, coeval with drowning of numerous Tethyan carbonate platforms, and pronounced Late Aptian regression marking a significant biological crisis in the peri-Adriatic region. The published data show that accumulation rates for the southern part of the Adriatic platform were 4 cm/k.y. on average, reaching a minimum value of less than 1 cm/k.y. in the Aptian. These low accommodation and accumulation rates likely caused amalgamated subtidal facies in the Early Aptian, and periodic emergence and well-developed paleosols in the Late Aptian. The thickness variations between the columns may be due to syndepositional tectonics combined with sea level oscillations.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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