Mid-early late Albian foraminiferal assemblage from the El Abra Formation in the El Madroño locality, eastern Valles–San Luis Potosí Platform, Mexico: Paleoenvironmental and paleobiogeographical significance

Omaña, Lourdes; Alencáster, Gloria; Buitrón, Blanca Estela

doi:10.18268/bsgm2016v68n3a6

Cited by 7 publications

(3 citation statements)

References 23 publications

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“…Thus, the unit is of latest early Berriasian age (i.e., the Elliptica Subzone of the Calpionella Zone). Berriasian age of the top of the Slivnitsa Formation and its cover in the neighbouring Beledie Han section was assumed by Sapunov et al (1985) and Nikolov and Tzankov (1998) on the basis of the calcareous algal species Cayeuxia kurdistanensis Elliott, 1956 that is a longer-ranging microfossil (Berriasian to Albian; see Omaña et al, 2016). Our present calpionellid results provide a more precise age determination.…”

Section: Clayey Limestone Unit At the Mezhdina Summitsupporting

confidence: 71%

Calpionellid biostratigraphy and microfacies analysis of a Tithonian–Berriasian carbonate succession in the Western Srednogorie (Bulgaria)

Petrova

Andreeva

Metodiev

et al. 2017

Geologica Balcanica

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In the eastern part of the Western Srednogorie Unit, around Dragovishtitsa Village, a specific succession of the Gintsi and Glozhene–Slivnitsa formations has provided micropalaeontological evidence for late Tithonian (Chitinoidella, Praetintinnopsella and the base of Crassicollaria zones) and mid-Berriasian (the Elliptica Subzone of the Calpionella Zone) age on the basis of 45 chitinoidellid and calpionellid species. A significant stratigraphic hiatus is documented within the Glozhene–Slivnitsa Formation, since a part of the Crassicollaria Zone, as well as the Alpina+Remaniella subzones of the Calpionella Zone, is absent from the Dragovishtitsa 1 section. The conformably overlying Salash Formation is of mid-Berriasian age (Elliptica Subzone) and is locally characterized by the presence of calcareous sandstones (Dragovishtitsa 2 section). The Salash–Cherni Osam Formation, as well as the clayey limestone unit covering the Slivnitsa Formation, is also of mid-Berriasian age (Elliptica Subzone). The Slivnitsa and Glozhene–Slivnitsa formations, which underlie the Salash–Cherni Osam Formation in the Dragovishtitsa East section, correspond to the Crassicollaria Zone and the Alpina Subzone, respectively. Reworking of calpionellids from the Crassicollaria Zone is documented in the Alpina and Elliptica subzones in all three studied sections. Eight microfacies types are distinguished, which suggests that the carbonate sediments were deposited in a carbonate platform rather than in a pelagic basin environment, althought the upper part of the studied sections reveals an upward-deepening trend. The Slivnitsa Formation is covered by highly diachronous sediments from more distal settings: from mid-Berriasian around Dragovishtitsa Village to the Berriasian/Valanginian transition at the Tri Ushi section to late Valanginian in the Dragoman and Kalotina sections. This fact, together with the significant stratigraphic hiatus within the Glozhene–Slivnitsa Formation, is interpreted here as tectonically controlled. The presence of transitional depositional settings from carbonate platform to deeper-marine environments caused deposition of specific lithostratigraphic units not always corresponding to the diagnostic features of the Glozhene, Salash and Cherni Osam formations.

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Section: Clayey Limestone Unit At the Mezhdina Summitsupporting

confidence: 71%

Calpionellid biostratigraphy and microfacies analysis of a Tithonian–Berriasian carbonate succession in the Western Srednogorie (Bulgaria)

Petrova

Andreeva

Metodiev

et al. 2017

Geologica Balcanica

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“…We studied the benthic foraminiferal community from the western part of the VSLPP. This association has been dated as middle-late Cenomanian and is very different from the well-known foraminiferal association of the eastern part composed mostly of orbitolinids (Omaña et al, 2016). The upper part of the El Abra Formation in the area of study represents the last shallow-water deposit preceding the VSLPP, which was drowning at the Cenomanian/Turonian boundary interval (Basañez et al, 1993;.…”

Section: Introductionmentioning

confidence: 78%

Mid-late Cenomanian larger benthic foraminifers from the El Abra Formation, Valles-San Luis Potosí Platform, central-eastern Mexico: Taxonomy, biostratigraphy and paleoenvironmental implications

Omaña¹,

López-Doncel²,

Torres³

et al. 2019

BOL. SOC. GEOL. MEX.

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“…The Las Cuevas-Río Verde cluster of fluorite deposits (Las Cuevas, El Realito, La Constancia, and El Refugio mines; Figures 1 and 2) is located in the Álvarez range (Sierra de Álvarez), about 40 km east of the city of San Luis Potosí, on the southwestern limit of the Valles-San Luis Potosí Jurassic-Cretaceous carbonate platform (VSLPP) [2,4,6,[13][14][15][16]. The carbonate sequences in the area correspond mostly to reef and platform facies that belong to the Albian-Cenomanian El Doctor and Abra formations [13][14][15], and they are topped by the Upper Cretaceous Soyatal Formation, which consists of shaly and limestone breccias [17][18][19] (Figure 2). The Cenozoic magmatism in the area occurs as Oligocene hypabyssal and volcanic rhyolites and dacites, and minor granodiorite [4][5][6] ( Figure 2).…”

Section: Local Geology and Fluorite Depositsmentioning

confidence: 99%

Giant Fluorite Mineralization in Central Mexico by Means of Exceptionally Low Salinity Fluids: An Unusual Style among MVT Deposits

et al. 2019

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The origin of the mineralization at the world-class Las Cuevas (the largest single fluorite deposit in the world) has been historically disputed, essentially between skarn-related and Mississippi Valley Type (MVT) models. A systematic study of fluid inclusions in these deposits revealed that they were formed by low temperature (49 to 177 °C) and low salinity (0 to 1.9 wt % NaCl equiv) fluids. The obtained δ13C (between −2.39 and 0.20‰ VPDB) and δ18O (between −14.03 and −7.37‰ VPDB) data from local host limestones agreed with regionally representative values in the literature. The obtained δ13C (between −15.60 and −12.99‰ VPDB) and δ18O (between −5.56 and −1.84‰ VPDB) data from hydrothermal calcite associated with fluorite mineralization indicated that the isotopic composition of hydrothermal fluids initially reflected buffering by the host rocks, and then recorded the interaction between meteoric water and basinal brines. It is likely that such processes occurred with concurrent maturation of organic matter, and that the obtained compositions may also have recorded a thermal effect on the local limestones. Halogen geochemical studies in inclusion fluids showed a distribution that suggests that solutes in mineralizing fluids were due to scavenging of Na+ and Cl− through water–rock interaction or halite dissolution, and that secondary sources would have been the evaporation or infiltration of seawater. The basinal brines with which the formation of these deposits was associated were massively diluted by deeply evolved meteoric water, thus making a significant fluorine input by basinal brines unlikely. Fluorine would have been provided by local groundwater through its interaction with Oligocene topaz rhyolites and other F-rich volcanic and hypabyssal rocks. Such a possibility is supported by present-day groundwater, which presents a regional endemic case of fluorosis. The precipitation of fluorite is possible at low temperatures (at which the solubility of this mineral is very low) by means of chemical reactions and physical interactions among very diluted F-poor basinal brines, F-rich groundwater, and host carbonate rocks. The latter systematically experienced hydrothermal karstification, which would have provided Ca2+ for reaction with F− and resulted in the precipitation of fluorite. This scenario stands for a depositional model that recalls those proposed for MVT and associated industrial mineral deposits, but is distinct from common models with regard to the primal source for fluorine and the extremely low salinities of inclusion fluids.

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Mid-early late Albian foraminiferal assemblage from the El Abra Formation in the El Madroño locality, eastern Valles–San Luis Potosí Platform, Mexico: Paleoenvironmental and paleobiogeographical significance

Cited by 7 publications

References 23 publications

Calpionellid biostratigraphy and microfacies analysis of a Tithonian–Berriasian carbonate succession in the Western Srednogorie (Bulgaria)

Calpionellid biostratigraphy and microfacies analysis of a Tithonian–Berriasian carbonate succession in the Western Srednogorie (Bulgaria)

Mid-late Cenomanian larger benthic foraminifers from the El Abra Formation, Valles-San Luis Potosí Platform, central-eastern Mexico: Taxonomy, biostratigraphy and paleoenvironmental implications

Giant Fluorite Mineralization in Central Mexico by Means of Exceptionally Low Salinity Fluids: An Unusual Style among MVT Deposits

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