Regional to global correlation of lower Cretaceous (Hauterivian-Barremian) shallow-water carbonates of the southern Apennines (Italy) and Dinarides (Montenegro), southern Tethyan Margin.
Academic Article
Publication Date:
2004
abstract:
We propose a high-resolution regional to global scale correlation of two Hauterivian/Barremian shallow water carbonate
platform sections belonging to different palaeogeographic domains of the Southern margin of the Tethys. These successions are
now located more than 500 km apart and are represented by 137 m of core drilled at Monte Raggeto (southern Apennines, Italy)
and by 80 m of well stratified rocks cropping out in the Podgorica Mountains (Dinarides, Montenegro). They display three
superimposed orders of stratigraphic cyclicity defined by elementary cycles grouped into bundles and superbundles and
attributed to orbitally induced composite sea-level fluctuations. Elementary cycles are interpreted as the precession and the
obliquity periodicities (2040 ky), while bundles and superbundles correspond to the short (100 ky) and long (400 ky)
eccentricity cycles, respectively. As both the ratios between the elementary cycles and the bundles and between the bundles and
the superbundles do not always reflect the classical 5:1 and 4:1 relationship, the sedimentary record of both the studied sections
is likely to include omission of bundles or their portion.
The general evolution of depositional and diagenetic facies, the vertical change in thickness of the cyclic units, and the
interpretation of superbundles as small-scale depositional sequences, suggest that elementary cycles and their groups are
superimposed on lower-frequency environmental oscillations. These display an upward Transgressive/Regressive Trend (T/RT)
of the facies and testify to larger-scale variations of accommodation potential on the shelf.
T/RTs, sequence stratigraphic interpretation of the superbundles as well as the common occurrence of the biostratigraphic
dated Hauterivian/Barremian boundary in the studied sections, support the long-distance regional correlation between the
successions to be carried out on the 100 ky scale. Moreover, by assuming the maximum flooding intervals of time-equivalent
superbundles as virtually isochronous intervals, we have detected stratigraphic gaps of 1200 and 600 ky in the Monte Raggeto
and in the Podgorica Mountains sections, respectively. Both sections are formed of 10 complete superbundles each of them
testifying to the 400-ky-long eccentricity. Hence, the Monte Raggeto and Podgorica Mountains successions represent a duration
of at least 4.0 My in terms of elapsed time, regardless of gaps within the stratigraphic record.
Finally, a correlation between the orbitally induced compared sections and both the 3rd order Tethyan stratigraphic cycles
and the global cycle chart is suggested.
Our study confirms that cyclically organized, shallow marine carbonate platform deposits controlled by orbitally induced
sea-level fluctuations represent a powerful tool for high-precision regional and global correlations. This can be of fundamental
importance for quantification of sedimentary, diagenetic, and evolutionary processes as well as for the understanding of
autocyclic versus allocyclic control on sequence development.
Iris type:
01.01 Articolo in rivista
Keywords:
Lower Cretaceous; Southern Tethys; Carbonate platform; Orbital cyclostratigraphy; High-resolution correlation
List of contributors:
Raspini, Arturo
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