Palaeoceanographic controls on reef deposition: the Messinian Cariatiz reef (Sorbas Basin, Almería, SE Spain)

The Cariatiz section lies at the toe of the palaeoslope of the Messinian Cariatiz
fringing reef, at the northern margin of the Neogene Sorbas Basin in SE Spain.
Distal-slope reef deposits in the upper part of the section can be traced laterally
to the reef core of the last episodes of reef progradation. The underlying
deposits are alternating diatomitic marl, marl and silty marl that intercalate
with sandstone beds. Combined lithological changes, variations in proportions
of warm-water planktic foraminifera and d18O values suggest that at least
seven, probably precessional, cycles are recorded throughout the Cariatiz
section. The correlation of seven cycles in the pelagic deposits to seven reef
progradation cycles, and associated vertical shifts in reef facies, indicates
relative sea-level oscillations of several tens of metres. Biostratigraphic and
palaeomagnetic data suggest that both the Cariatiz section and the fringing reef
formed during the reverse polarity Chron C3r. Surface-water temperatures
seem to be the major factor controlling carbonate production in the reef system.
Deposition of bioclastic calcirudite and calcarenite, with no active coral
growth, took place at the lowest sea-level within each reef cycle during
temperature minima within each precessional cycle. Porites framework and
reef-slope deposits with Halimeda gravel, in contrast, formed during
temperature rises and thermal maxima within precessional cycles.