Facies evolution and sequence chronostratigraphy of a “mid”-Cretaceous shallow-water carbonate succession of the Apulia Carbonate Platform from the northern Murge area (Apulia, southern Italy)

Abstract

The "mid"-Cretaceous carbonate succession of the Apulia Carbonate Platform cropping out in northern Murge area (Apulia, southern Italy) is composed of shallow-water carbonate rocks and is over 400 m in thickness. This paper focuses on the lithofacies analysis of this carbonate succession, its paleoenvironmental interpretation, and its sequence-chronostratigraphic architecture. Lithofacies analysis permitted to identify deposits which can be grouped into the following three facies belts: (1) terrestrial facies belt formed by: intraclast-supported paleosoils; solution-collapse breccias; (2) restricted facies belt made up of lithofacies deposited in protected peritidal environments;(3) normal-marine facies belt made up of lithofacies formed in moderate-to high-energy subtidal environments. The detailed study both in outcrops and in thin-sections revealed that, at the bed scale, lithofacies are cyclically arranged and form shallowing-upward small-scale depositional sequences comparable to parasequences and/or simple sequences. The following three small-scale sequence types have been distinguished: (1) subtidal sequences mostly made up of lithofacies formed in the normal-marine open subtidal domain; (2) peritidal sequences made up of lithofacies formed in the restricted peritidal domain; (3) peritidal sequences showing a cap formed by paleosoils.Small-scale sequences are not randomly arranged in the compiled succession but form discrete packages, or sets, that alternate in the sedimentary record. The repetition of such small-scale sequence packages in the succession has been the key to recognize large-scale sequences comparable to third-order depositional sequences. Although sedimentological data are often fragmentary due to late dolomitization, four large-scale sequences have been distinguished. The data support a generalized landward-backstepping of facies belts during transgression, which implies a gradual gain of accommodation culminating with the deposition of a package of small-scale sequences formed by normal-marine subtidal deposits. These mark periods of maximum accommodation space and form the maximumXooding zones of large-scale sequences. A gradual seaward progradation of facies belts is recorded during highstand conditions, which implies a gradual loss of accommodation culminating with the deposition of a package of peritidal small-scale sequences capped by paleosoils or by solutioncollapse breccias. The occurrence of terrestrial deposits marks periods of minimum accommodation on the platform and determines the sequence boundary of large-scale sequences. The large-scale sequences identiWed in this study Wt with the main transgressive/regressive cycles published in the sequence-chronostratigraphic chart of European basins. As a consequence, it is interpreted that changes of the sea level recorded at the scale of European basins played an important role in determining the sequence-stratigraphic architecture of the studied succession. In spite of this, the occurrence of solution-collapse breccias, which impli...

Bedding-parallel stylolites in shallow-water limestone successions of the Apulian Carbonate Platform (central-southern Italy)

“…This was responsible for accumulation of some km-thick successions of shallow-water carbonates (limestones and minor dolomites) characterized by pronounced facies cyclicity and (100's of meters to kilometers) laterally continuous beds (ACCARIE et alii, 1986;BOSELLINI et alii, 1999;BORGOMANO, 2000;SPALLUTO et alii, 2005;SPALLUTO, 2012). Limestones are mostly mud-dominated, although grain-dominated and bioconstructed ones (among which stromatolitic limestones) also occur.…”

“…Stromatolitic limestones (including subtly laminated fenestral calcilutites) accumulated in low energy, intertidal to supratidal environments (VECSEI et alii, 1998;BOSELLINI et alii, 1999;BORGOMANO, 2000;SPALLUTO et alii, 2005;SPALLUTO, 2012).…”

“…Microfacies indicate deposition in sub-tidal environments, more high-energy and open than those in which calcilutites accumulated (BOSELLINI et alii, 1999;SPAL-LUTO et alii, 2005;SPALLUTO, 2012).…”

“…The remainder of lithologies, documented only in the Maiella Mountain and/or the Murge Plateau and accounting only for 0-10% by volume, consists of (mostly) discontinuous beds of i) calcirudites (rudist rudstones plus floatstones) and ii) platform emersion-related lithologies (e.g., SPALLUTO, 2012), namely (calcrete-bearing) residual clays and intraformational (blackened clasts-or residual clay-bearing) calcareous breccias. Both lithological classes are not considered in the next paragraphs because they are volumetrically scarce and the latter is unsuitable to undergo pressure solution as well.…”

Did Adria rotate relative to Africa?

“…In the Murge area ( Fig. 2), where its age has been best constrained (Spalluto et al, 2005;Spalluto and Caffau, 2010;Spalluto, 2011), the succession forms a monocline dipping gently towards the SSW, thus exposing younger rocks from NNE to SSW (Ciaranfi et al, 1988) (Fig. 2).…”