Introduction ] [ 2. Geological background and methods ] [ 3. Results ] [ 4. Discussion ] [ 5. Published online in final form pdf on July 21, DOI A rich geobiological record of Cretaceous biotic and abiotic interactions around Cupido mexico proto-Gulf of Mexico has been preserved in the massive Cupido carbonate platform, i. This work documents lateral facies variation on a dip slope reef from a new outcrop in the Cupido mexico part of the Cupido Formation in the state of Nuevo Leon, Mexico.
The measured transect is correlated with a stratigraphic column logged in a nearby section. The preserved fossil biota represents marginal reef facies dominated by abundant rudist shells such as Douvillelia skeltoniToucasia sp. Benthic foraminifers miliolids and textularids with associated dasycladalean algae such as Salpingorella sp. This facies is overlain by a thin cm stromatolite horizon at the upper end of the measured section. This locality represents a new paleobiological and taphonomic window into one of the most extensive carbonate platform system developed along the margin of the Gulf of Mexico during the Cretaceous.
Torres de la Cruz F. In Cupido mexico, massive Cupido mexico platforms formed in low amplitude and high-frequency eustatic cycles shallow carbonates cycles on the scale of s to s to 10s of s of yearscomposed of peritidal carbonates in the ancestral Gulf of Mexico from the Barremian to the Cupido mexico Lehmann et al.
Cretaceous sedimentary rocks are well-represented in several states of northeastern Mexico, particularly in Nuevo Leon, where massive limestones from the Cupido Formation crown the uppermost part Cupido mexico the Sierra Madre Oriental SMO and line up in superb scenic views around the area of Monterrey Fig. Click on thumbnail to enlarge the image. The Cupido Formation developed as a reef-rimed carbonate platform composed of corals, stromatoporoids, sponges, rudists, green algae, and benthic foraminifera Wilson Although the large-scale platform paleo-configuration was proposed almost twenty years ago Goldhammer, little work has been devoted to lateral sedimentological and bathymetric variations at smaller scales.
Most previous works Conklin and Moore, Cupido mexico reported the great variability in thickness of this formation, ranging from a few hundred meters of thickness near Saltillo to approximately m near Monterrey both cities separated by an approximate distance of 60 km and up to m at Minas Viejas Wilson and Pialli, located 40 km north of Monterrey.
After the Cupido mexico of Pangea and during the subsequent rifting and drifting stages, several basins developed in northeastern Mexico in a process that also generated the Jurassic Louann Salt deposits in Texas and the Campeche Salt basin.
The resulting accommodation space was filled by thick carbonate systems. In this way, the thermal contraction of tectonic plateaus allowed the development of carbonate platforms in this region. The Cupido platform, coeval with the Sligo platform in Texas Lehmann et al.
Johnson, is part of one of most extensive carbonate systems extending over an area of approximately 80, Cupido mexico 2 Lehmann et al. As the main lithostratigraphic unit of the Barremian-Aptian carbonate platform, the Cupido Formation hereafter CFwas defined by Imlay on the Based on chronostratigraphic data and facies association, Lehmann et Cupido mexico.
The CF originated as an extensive coastal lagoon with peritidal carbonate cycles between the basement of the Coahuila Block Fig.
This small locality exposes fossiliferous limestones with sub-horizontal stratification but lacks any close stratigraphic references and follows a trend parallel to the land surface, precluding a good stratigraphic control. However, the abundance and size of fossils deserved a closer examination.
Even where massive grey strata were visible at the basal lateral side at the western side of the outcropstratification is fully-covered by vegetation, by Quaternary sediments and by coquinas composed of reworked fossiliferous material from the Cupido. All measurements were taken through the hill scarp, without further stratigraphic control during fieldwork campaigns from February to In order to place this transect into the Cupido Formation, the outcrop has been correlated with a stratigraphic column that was logged on the west-facing hill less than one kilometer northwest of the transect.
The Cupido mexico section was located by 21 GPS Global Positioning System spots for reference; structural strike and dip data were taken for stratigraphic control Fig. Based on this reference profile, it is assumed that the studied section corresponds with the upper part of the Cupido and Cupido mexico lateral facies variations along Cupido mexico dip slope Cupido mexico at one end by lagoonal facies and at the other by reef facies. About 50 petrographic thin sections were made for petrographic analysis.
Where possible, macrofossils identified in the field were collected, but the largest rudists and corals remained in dolomitized limestones in situ. Grey and brown thick-bedded to massive limestones lie on an overturned-fold structure with a NW-SE-orientation. The geological open polygon on Cupido mexico A-A' blue line derives from structural data of the geological section modified from Torres de la Cruz The PM locality is located between two hills as shown in the geologic map of Figure 4.
The first vertical section was measured on the flat hill marked as I, and the second vertical section used as reference is located on the hill marked as II Fig. The dominant lithology is composed of highly-recrystallized Cupido mexico fractured light-brown limestone Fig. C-Dmostly fractured and filled with calcite. The description of the reference transect II Figs. Cupido mexico reference section at the PM locality. B A south-facing panoramic view from the PM outcrop.