GEOL 340 Sedimentology and Stratigraphy
Lecture 36
Case Study: Seroe Domi Formation, Netherlands Antilles
Fouke, B.W., Meyers, W.J., Hanson, G.N., and Beets, C.J., 1996,
Chronostratigraphy and dolomitization of the Seroe Domi Formation,
Curacao, Netherlands Antilles. Facies, v. 35, p. 293-320.
Fouke, B.W. and Reeder, R.J., 1992, Surface structural controls
on dolomite composition: Evidence from compositional sector zoning.
Geochimica et Cosmochimica Acta, v. 56, p. 4015-4024.
Fouke, B.W., 1994, Deposition, Diagenesis and Dolomitization of
the Neogene Seroe Domi Coral Reef on Curaçao, Netherlands
Antilles. Publications Foundation for Scientific Research in
the Caribbean Region, Amsterdam, v. 135, 197 pp.
Abstract from Fouke et al. (1996)
The Seroe Domi Formation is a 350 m-thick sequence of Neogene
marine limestones and silicilastic sandstones cropping out on
the leeward coast of Curaçao, Netherlands Antilles. Integrated
litho-, bio-, chemostratigraphy and Sr isotope model age analyses
indicate that Seroe Domi Formation is composed of three discontinuous
Mio-Plio-Pleistocene depositional events (Subunits 1, 2, and 3)
that experienced three distinct Mio-Plio-Pleistocene episodes
of dolomitization (Dolomites I, I', and II).
Subunit 1, the lowermost 30 to 100 m of the Seroe Domi Formation,
is composed of interbedded coralgal grainstone gravity flows,
pelagic wackestones, and allochthonous blocks deposited in deep-water
(>500 m) fore-reef and carbonate slope environments during
the Middle Miocene. Subunit 2, the uppermost 250 m of the Seroe
Domi Formation, consists of coralgal packstones with basement-derived
siliciclastic sands that were deposited in shallowing fore-reef
to reef-front environments during the Late Miocene to Pliocene.
Subunit 3 siliciclastic sandstones were deposited during the
Early Pleistocene within erosional cavities in the Subunit 2 limestones,
which are overlain by Late Pleistocene Quaternary Limestone Terraces.
The distribution and geochemistry of Dolomites I, I' and II indicate
that they were precipitated from multiple Neogene seawater-freshwater
mixing zone fluid environments. Biomolds containing dolomite,
altered skeletal material and meteoric calcite cementation demonstrate
that the host Seroe Domi Formation limestones were subaerially
exposed prior to, and/or synchronous with, each dolomitization
event. Dolomite I (*18O = +1.04 to +2.46 o/oo PDB; *13C = -2.55
to -6.79 PDB; 87Sr/86Sr = 0.708866 to 0.708915; Zn = 0 ppm; Cu
= 0 ppm) was precipitated from mixtures of seawater with isotopically-depleted
freshwater during the Middle to Late Miocene. Dolomite I' (*18O
= +2.08 - +3.55 PDB, *13C = -1.53 - +1.69 PDB, 87Sr/86Sr = 0.708981
- 0.709030; Zn = 0 ppm; Cu = 0 ppm) was also precipitated from
mixtures of seawater with isotopically-depleted freshwater, but
during a later Late Miocene to Pliocene episode. Dolomite I and
I' cathodoluminescent crystal zonations document an intermediate
change in dolomitizing water equilibria from saturation to undersaturation
with respect to calcite. In contrast, Dolomite II (*18O = +2.69
to +3.51 PDB; *13C = -0.34 to +1.53 PDB; 87Sr/86Sr = 0.708954
to 0.709088; Zn = 20 ppm; Cu = 20 ppm) precipitated from Pliocene-Early
Pleistocene mixtures of seawater with isotopically-depleted freshwater
that contained less-radiogenic Sr, Zn and Cu derived from basalts
of the Curaçao basement.