Stratigraphy and Palaeobiogeography of Mesozoic Benthic Foraminifera - Part 2

Abstract

The Adriatic Carbonate Platform (AdCP), was a separate shallowmarine depositional system characterized by a lack of terrigenous input and was connected to Gondwana towards the South via Gavrovo–Tripolitza or Apulia. It existed for approximately 120 MY, from the Early Jurassic Pliensbachian/Toarcian) to the end of the Cretaceous, resulting in a 4000–6500 m thick succession of almost pure carbonates. However, this is part of a thicker (>8000 m) sequence of predominantly carbonate rocks which forms the Karst Dinarides, and was deposited during more than 270 MY – at least from the Carboniferous (Moscovian) to the Late Eocene. Among many different groups of fossil organisms, benthic foraminifera are especially abundant and well preserved, so they, along with calcareous algae (Dasycladales), are the most important fossils used for age determination and stratigraphic subdivision of shallow-marine carbonate deposits. Within the 257 determined taxa belonging to different foraminiferal families which lived through the Mesozoic, numerous different index fossils occur in assemblages indicating various ages: Early Triassic, Anisian, Carnian, Norian–Rhaetian, Late Sinemurian, Early and Late Pliensbachian (Carixian and Domerian), Early and Late Aalenian, Early and Late Bajocian, Early and Late Bathonian, Callovian, Early and Late Oxfordian, Kimmeridgian, Tithonian, Berriasian, Valanginian, Late Hauterivian, Late Barremian, Early and Late Aptian (Bedulian and Gargasian), Early and Late Albian, Early, Middle and Late Cenomanian, Turonian, Coniacian, Santonian, Early and Late Campanian and Early and Late Maastrichtian. A total of 64 biostratigraphic units – biozones of different categories, from subzone to superzone, were defined within the stratigraphic interval from the Carnian to the Late Maastrichtian. This enabled very detailed biostratigraphic subdivision of the carbonate deposits within the Karst Dinarides. This is one of the most precise sequences, not only in this area, but also among former shallow marine deposits of the entire Neotethyan realm in the present Mediterranean region. The palaeobiogeographic characteristics of biotopes and the composition of foraminiferal assemblages during the Mesozoic were controlled by the position of the study area within the Neotethyan bioprovinces. Until the Albian, this area represented part of the Southern Neotethyan bioprovince, while from the Cenomanian to its final disintegration at the end of the Cretaceous it belonged to a separate, Central Mediterranean Neotethyan bioprovince.

Proliferation of Chondrodonta as a proxy of environmental instability at the onset of OAE1a: Insights from shallow‐water limestones of the Apulia Carbonate Platform

“…The biostratigraphic schemes proposed in Claps et al . (1996) for the SGRL were updated based on more recent reviews of dasycladales (Carras et al ., 2006) and of benthic foraminifera (Velić, 2007; Schröeder et al ., 2010; Chiocchini et al ., 2012).…”

“…Depositional textures for lithofacies definition were analysed semi-quantitatively and expressed in terms of relative abundance. The biostratigraphic schemes proposed in Claps et al (1996) for the SGRL were updated based on more recent reviews of dasycladales (Carras et al, 2006) and of benthic foraminifera (Veli c, 2007;Schr€ oeder et al, 2010;Chiocchini et al, 2012).…”

Assessing Milankovitch forcing in disconformity‐prone cyclic shallow‐water carbonates, Upper Jurassic (Kimmeridgian), Adriatic Platform, Croatia

“…Ages of Upper Jurassic units of the Adriatic Platform are based on benthic foraminifera and calcareous algae. The Late Jurassic−earliest Cretaceous has several index species and biozones in the benthic foraminifera (Husinec et al ., 2000; Husinec & Sokač, 2006; Velić, 2007), whereas the Upper Jurassic dasycladalean algae form four distinct biozones (Nikler & Sokač, 1968; Velić, 1977; Velić & Sokač, 1978; Sokač et al ., 2014; Prtoljan et al ., 2015). In addition to the biostratigraphic control, δ 13 C chemostratigraphic profiles from the section were compared with other European δ 13 C profiles (Price & Rogov, 2009; Nunn & Price, 2010; Colombié et al ., 2011; Price et al ., 2016) to further constrain the stage boundaries (Fig.…”

“…There are numerous quantitative studies involving spectral analysis of deeper-marine Upper Jurassic units for cyclostratigraphy and astrochronology, because the records are relatively continuous and preserve a spectrum of forcing frequencies (Hinnov, 2018, and references therein;Huang, 2018, Kietzmann et al, 2020. In contrast, there are few quantitative studies of Upper Jurassic shallow-water carbonates because of the potential for numerous stratigraphic gaps associated with disconformities and missed beats (Strasser, 1994;Husinec & Read, 2006, 2007.…”

“…This paper helps to address this gap by a quantitative study of ca 260 m thick, 5.8 AE 0.1 Myr record of the exposed Upper Jurassic (Kimmeridgian to basal Tithonian) succession of the Adriatic Carbonate Platform, Croatia (Figs 1 to 3) which is dominated by metre-scale parasequences interrupted by several subaerial breccia horizons. Published ages of the succession based on benthic foraminifera and calcareous green algae (Nikler & Soka c, 1968;Veli c, 2007) along with a comparison of our d 13 C curves with global profiles (Nunn & Price, 2010;Colombi e et al, 2011;Price et al, 2016), and the updated Haq (2018) global sequence chart were used to constrain the ages. The spectral analysis Acycle v. 2.2 package was used (Li et al, 2019a) to rigorously analyze time series constructed from water-depth rank versus stratigraphic position and parasequence-thickness versus stratigraphic position for evidence of astronomical forcing.…”