El Pedregal Formation Explained

El Pedregal Formation
Period:Aalenian
Type:Geological formation
Prilithology:Mudstone limestones and wakestone limestones
Underlies:
  • Moscardón Formation
Overlies:
  • Casinos Formation
  • Turmiel Formation
Thickness:>150 m
Area:Levantine sector
Location:Levantine sector
Coordinates:40°10′27.1”N 1°00′50.7”W
Region:Iberian Basin
Thickness Ts:~150m (490feet)

The El Pedregal Formation is a geological formation of Early Aalenian-Early Bajocian (Middle Jurassic) age in the Iberian Basin of W Iberian Peninsula.[1] [2] [3] This is allocated in the East-Iberian area, that during the Middle Jurassic was part of a Carbonate platform system, influenced by tectonic activity and fault lines, along the Iberian and Catalan Coastal mountain ranges of Spain, with an exposure of up to 500 km.[4] This carbonates are allocated on the Chelva Group, that was network of carbonate platforms, with shallow areas forming around elevated blocks created by tectonic forces.[5] [6] Deeper marine environments developed between these blocks, which were likely connected to the open ocean. The Internal Castilian Platform was linked to the Iberian Massif, while the El Maestrazgo High separated two marine platforms: the External Castilian and Aragonese. Further to the northeast, the Tortosa Platform was bordered by the Tarragona High and Catalan Massif to the north and the El Maestrazgo High to the south. The Beceite Strait acted as a transition zone between the Aragonese and Tortosa platforms.[7]

Paleoenvironment

The El Pedregal Formation lithology is dominated by mudstone and wackestone limestones with fine sediments, including microfilaments, echinoderm fragments, and pellets, with less important sequences with interbedded marls, which are indicative of a low-energy marine environment.[8] [9] Associated with a shallow carbonate sea, sequences of this formation developed on a confined lagoon, relatively shallow and protected from direct oceanic influence by a volcanoclastic barrier.

This lagoon was developed adjacent or inside an epehemeral volcanic island, shielded from ocean waves by deposits of volcanic materials.[10] Within these calm lagoon settings, carbonate sediments mixed with fine particles that contained plant fossils, preserving evidence of plant-insect interactions, with a low diversity of plants, mainly cycadophytes and ferns.[11] Occasionally, storm events would disrupt nearby oyster banks, carrying marine debris, including oysters, into the lagoons, sometimes interspersed with plant remains.

This ephemeral island/islands were situated more than 150 km from the nearest mainland, the Catalan and Iberian Massifs. Following the lagoonal deposits, considered of early Aalenian age, a large regional transgression in the late Aalenian impacted the local platform, connecting the Proto-Atlantic Ocean with the Western Tethys Ocean. Latter in the Bajocian the area evolved into a shallow external marine platform with frequent emersions.

Pelagic/open marine sequences are also common within the formation, including the "Albarracinites beds".[12] At The Masada Toyuela site taphonomic patterns indicate two contrasting sedimentary environments, with taphonic populations dominating in shallow-water settings, marked by reworked and abraded ammonite molds and chambers under slow sediment accumulation punctuated by rapid episodes due to currents and sediment bypassing. Conversely, deeper, sediment-starved areas feature "type 1" taphonic populations, characterized by juvenile, undamaged ammonites within homogeneous molds, typical of condensed deposits from transgressive phases.

Fossil Content

Brachiopoda

GenusSpeciesLocationMaterialNotesImages
Pseudogibbirhynchia
  • P. mutans
  • Abejuela outcrop
Isolated shellsAn Brachiopod of the family Basiliolidae
Prionorhynchia
  • P. rubrisaxensis
  • Abejuela outcrop
Isolated shellsAn Brachiopod of the family Prionorhynchiidae

Mollusca

GenusSpeciesLocationMaterialNotesImages
Abbasites
  • A. spp.
  • Caudiel outcrop
  • Pina-Barracas.1
  • Pina-Barracas.2
  • Sarrión.1
  • Sarrión.2
Isolated shellsAn Ammonite of the family Erycitidae
Abassitoides
  • A. spp.
  • Pina-Barracas.2
  • Sarrión.1
  • Sarrión.2
Isolated shellsAn Ammonite of the family Erycitidae
Albarracinites
  • A. albarraciniensis
  • Masada Toyuela
  • Cea de Abarracín
  • Moscardon
  • Vibei
Isolated shellsAn Ammonite of the family Stephanoceratidae
Ambersites
  • A. spp.
  • Caudiel outcrop
Isolated shellsAn Ammonite of the family Hammatoceratoidea
Apedogyria
  • A. spp.
  • Pina-Barracas.2
  • Sarrión.3
Isolated shellsAn Ammonite of the family Graphoceratidae
Brasilia
  • B. spp.
  • Caudiel outcrop
  • Pina-Barracas.1
  • Pina-Barracas.2
  • Sarrión.1
  • Sarrión.2
  • Sarrión.3
Isolated shellsAn Ammonite of the family Graphoceratidae
Chondroceras
  • C. spp.
  • Pina-Barracas.1
Isolated shellsAn Ammonite of the family Sphaeroceratidae
Elatmites
  • E. spp.
  • Caudiel outcrop
Isolated shellsAn Ammonite of the family Perisphinctidae
Eudmetoceras
  • E. spp.
  • Caudiel outcrop
  • Pina-Barracas.1
Isolated shellsAn Ammonite of the family Hammatoceratoidea
Euhoploceras
  • E. spp.
  • Pina-Barracas.2
  • Sarrión.1
  • Sarrión.2
Isolated shellsAn Ammonite of the family Sonniniidae
Epalxites
  • E. spp.
  • Pina-Barracas.1
Isolated shellsAn Ammonite of the family Sphaeroceratidae
Fontannesia
  • F. ssp.
  • Caudiel outcrop
Isolated shellsAn Ammonite of the family Sonniniidae
Graphoceras
  • G. spp.
  • Caudiel outcrop
  • Pina-Barracas.1
  • Pina-Barracas.2
  • Sarrión.1
  • Sarrión.2
Isolated shellsAn Ammonite of the family Graphoceratidae
Haplopleuroceras
  • H. mundum
  • H. subspinatum
  • H. crassum
  • H. spp.
  • Caudiel outcrop
  • Pina-Barracas.1
  • Pina-Barracas.2
  • Sarrión.1
  • Sarrión.2
Isolated shellsAn Ammonite of the family Hammatoceratoidea
Leptosphinctes
  • L. spp.
  • Caudiel outcrop
Isolated shellsAn Ammonite of the family Perisphinctidae
Ludwigella
  • L. spp.
  • Caudiel outcrop
  • Pina-Barracas.1
  • Pina-Barracas.2
  • Sarrión.1
  • Sarrión.2
Isolated shellsA Bivalve of the family Graphoceratidae
Macrocephalites
  • M. spp.
  • Caudiel outcrop
Isolated shellsAn Ammonite of the family Macrocephalitidae
Oppelia
  • O. spp.
  • Pina-Barracas.1
Isolated shellsAn Ammonite of the family Oppeliidae
Rhodaniceras
  • O. spp.
  • Caudiel outcrop
Isolated shellsAn Ammonite of the family Hammatoceratoidea
Pleydellia
  • P. aalensis
  • P. mactra
  • P. fluens
  • P. subcomp
  • P. ssp.
  • Caudiel outcrop
Isolated shellsAn Ammonite of the family Hildoceratidae
Sonninia
  • S. spp.
  • Sarrión.1
  • Sarrión.2
  • Sarrión.3
Isolated shellsAn Ammonite of the family Sonniniidae
Spiroceras
  • S. spp.
  • Caudiel outcrop
Isolated shellsAn Ammonite of the family Spiroceratidae
Stemmatoceras
  • S. spp.
  • Pina-Barracas.1
Isolated shellsAn Ammonite of the family Stephanoceratidae
Stephanoceras
  • S. spp.
  • Pina-Barracas.1
Isolated shellsAn Ammonite of the family Stephanoceratidae
Toxamblyites
  • T. spp.
  • Pina-Barracas.1
Isolated shellsAn Ammonite of the family Haploceratidae
Westermannites
  • W. ssp.
  • Pina-Barracas.2
  • Sarrión.1
  • Sarrión.2
Isolated shellsAn Ammonite of the family Sphaeroceratidae

Insecta

Foliar remains with insect interactions are common, including traces of margin feeding, Hole feeding, mining, oviposition, piercing and sucking and surface feeding. Due to be located adjacent to an isolated island, the Camarena locality insect biota likely wasn't too specialized, with generalists more likely to adapt to these environments and inflict similar damage.

Modern equivalents capable of leave similar patterns in extant cycadophytes include caterpillars from genera like Eumaeus (Lycaenidae) and Chilades, along other lepidopteran families, such as Tineidae, Nymphalidae, and Erebidae. Other insects capable of attack cycads include Hemipterans like Aulacaspis yasumatsui or the beetle Brachys cleidecostae (Buprestidae).

Bryophyta

GenusSpeciesStratigraphic positionMaterialNotesImages
Foveosporites
  • F. visscheri
  • TE-620 road
MiosporesIncertae sedis; affinities with Bryophyta.
Interulobites
  • I. spp
  • TE-620 road
MiosporesIncertae sedis; affinities with Bryophyta.
Polycingulatisporites
  • P. circulus
  • TE-620 road
MiosporesIncertae sedis; affinities with Bryophyta.

Lycophyta

GenusSpeciesStratigraphic positionMaterialNotesImages
Leptolepidites
  • L. macroverrucous
  • L. sp
  • TE-620 road
MiosporesAffinities with the family Lycopodiaceae in the Lycopodiopsida.
Lycopodiacidites
  • L. rugulatus
  • TE-620 road
MiosporesAffinities with the family Lycopodiaceae in the Lycopodiopsida.
Staplinisporites
  • S. caminus
  • TE-620 road
MiosporesAffinities with the family Lycopodiaceae in the Lycopodiopsida.
Uvaesporites
  • U. argenteaeformis
  • TE-620 road
MiosporesAffinities with the Selaginellaceae in the Lycopsida.

Pteridophyta

GenusSpeciesStratigraphic positionMaterialNotesImages
Biretisporites
  • B. potoniaei
  • TE-620 road
MiosporesAffinities with the families Schizaeaceae/Anemiaceae inside Pteridophyta
Baculatisporites
  • B. comaumensis
  • TE-620 road
MiosporesAffinities with the family Osmundaceae in the Polypodiopsida.
Cibotiumspora
  • C. jurienensis
  • C. juncta
  • TE-620 road
MiosporesAffinities with the family Cyatheaceae and Dicksoniaceae in the Cyatheales. Arboreal fern spores.
Contignisporites
  • C. sp.
  • TE-620 road
MiosporesAffinities with the families Schizaeaceae/Anemiaceae inside Pteridophyta
Deltoidospora
  • D. toralis
  • D. spp.
  • TE-620 road
MiosporesAffinities with the family Cyatheaceae and Dicksoniaceae in the Cyatheales. Arboreal fern spores.
Dictyophyllidites
  • D. sp.
  • TE-620 road
MiosporesAffinities with Matoniaceae/Weichseliaceae in the Gleicheniales.
Echinasporis
  • E. sp.
  • TE-620 road
MiosporesIncertae sedis; affinities with the Pteridophyta
Gleicheniidites
  • G. senonicus
  • TE-620 road
MiosporesAffinities with the Gleicheniales in the Polypodiopsida. Fern spores from low herbaceous flora.
Granulatisporites
  • G. sp.
  • TE-620 road
MiosporesIncertae sedis; affinities with the Pteridophyta
Ischyosporites
  • I. crateris
  • I. marburgensis
  • TE-620 road
MiosporesAffinities with the families Schizaeaceae/Anemiaceae inside Pteridophyta
Kekryphalospora
  • K. sp. cf. K. distincta
  • TE-620 road
MiosporesAffinities with the families Schizaeaceae/Anemiaceae inside Pteridophyta
Klukisporites
  • K. variegatus
  • K. spp.
  • TE-620 road
MiosporesAffinities with the family Lygodiaceae in the Polypodiopsida. K. variegatus is the 2nd most abundant palynomorph (20%)
Leptolepidites
  • L. macroverrucosus
  • L. sp.
  • TE-620 road
MiosporesAffinities with the family Dennstaedtiaceae in the Polypodiales. Forest fern spores.
Lycopodiacidites
  • L. rugulatus
  • TE-620 road
MiosporesAffinities with the Ophioglossaceae in the Filicales. Fern spores from lower herbaceous flora.
Manumia
  • M. irregularis
  • TE-620 road
MiosporesIncertae sedis; affinities with the Pteridophyta
Matonisporites
  • M. phlebopteroides
  • TE-620 road
MiosporesAffinities with Matoniaceae in the Gleicheniales.
Osmundacidites
  • O. wellmani
  • TE-620 road
MiosporesAffinities with the family Osmundaceae in the Polypodiopsida.
Skarbysporites
  • S. crassexinius
  • TE-620 road
MiosporesIncertae sedis; affinities with the Pteridophyta
Todisporites
  • T. major
  • TE-620 road
MiosporesAffinities with the family Osmundaceae in the Polypodiopsida.

Cycadophytes

GenusSpeciesStratigraphic positionMaterialNotesImages
Cycadopites
  • C. cf. carpentier
  • C. follicularis
  • TE-620 road
PollenAffinities with the family Cycadaceae in the Cycadales and with Bennettitales.
CycadophytaIndeterminate
  • TE-620 road
Multiple LeafletsAffinities with Cycadales in the Cycadopsida. The local macroflora is dominated by Cycadophytes
Monosulcites
  • M. minimus
  • TE-620 road
PollenAffinities with Cycadales in the Cycadopsida.

Coniferophyta

GenusSpeciesStratigraphic positionMaterialNotesImages
Araucariacites
  • A. australis
  • TE-620 road
PollenAffinities with Araucariaceae in the Pinales. The Camarena palynoflora is dominated by Araucariacites australis (58%)
Callialasporites
  • C. turbatus
  • TE-620 road
PollenAffinities with the family Araucariaceae in the Pinales. Conifer pollen from medium to large arboreal plants.
Classopollis
  • C. classoides
  • TE-620 road
PollenAffinities with the Hirmeriellaceae in the Pinopsida.
Sciadopityspollenites
  • S. macroverrucosus
  • S. spp.
  • TE-620 road
PollenAffinities with both Sciadopityaceae and Miroviaceae in the Pinopsida. This pollen's resemblance to extant Sciadopitys suggest that Miroviaceae may be an extinct lineage of Sciadopityaceae-like plants.[13]
Spheripollenites
  • S. psilatus
  • TE-620 road
PollenAffinities with the Hirmeriellaceae in the Pinopsida.

See also

References

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  2. Santos . Artai A. . Sender . Luis M. . Wappler . Torsten . Engel . Michael S. . Diez . José B. . 2021 . A Robinson Crusoe story in the fossil record: Plant-insect interactions from a Middle Jurassic ephemeral volcanic island (Eastern Spain) . Palaeogeography, Palaeoclimatology, Palaeoecology . 583 . 110655 . 10.1016/j.palaeo.2021.110655 . 2021PPP...58310655S . 0031-0182. 11093/2633 . free .
  3. Cortés . José Emilio . 2023-06-12 . Dating volcanic materials through biochronostratigraphic methods applied to hosting strata (example from the Iberian Chain, eastern Spain) . Comptes Rendus. Géoscience . 355 . G1 . 175–202 . 10.5802/crgeos.220 . 2023CRGeo.355..175C . 1778-7025. free .
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  5. Gómez . J. J. . Goy . A. . 1979 . Las unidades litoestratigraficas del Jurasico medio y superior, en facies carbonatadas del Sector Levantino de la Cordillera Iberica [España] ]. Estudios geológicos . 35 . 1–683.
  6. García-Frank . Alejandra . Ureta . Soledad . Mas . Ramón . 2008 . Aalenian pulses of tectonic activity in the Iberian Basin, Spain . Sedimentary Geology . 209 . 1–4 . 15–35 . 10.1016/j.sedgeo.2008.06.004 . 2008SedG..209...15G . 0037-0738.
  7. Cortés . J.E. . Gómez . J.J. . 2016-12-22 . Middle Jurassic volcanism in a magmatic-rich passive margin linked to the Caudiel Fault Zone (Iberian Range, East of Spain): biostratigraphical dating . Journal of Iberian Geology . 42 . 3 . 10.5209/jige.54667 . 1886-7995.
  8. Gómez . Juan J. . Goy . Antonio . 2005 . Late Triassic and Early Jurassic palaeogeographic evolution and depositional cycles of the Western Tethys Iberian platform system (Eastern Spain) . Palaeogeography, Palaeoclimatology, Palaeoecology . 222 . 1–2 . 77–94 . 10.1016/j.palaeo.2005.03.010 . 2005PPP...222...77G . 0031-0182.
  9. Cortés . J.E. . 2019 . La Arquitectura Deposicional de los Carbonatos del Jurásico Inferior y Medio Relacionados con los Materiales Volcánicos del Sureste de la Cordillera Ibérica . PhD Dissertation. Ed. Electrónica Universidad Complutense de Madrid, Madrid . 1–1330.
  10. Cortés . J. E. . Gómez . J. J. . 2018-04-16 . The epiclastic barrier-island system of the Early‒Middle Jurassic in eastern Spain . Journal of Iberian Geology . 44 . 2 . 257–271 . 10.1007/s41513-018-0061-7 . 2018JIbG...44..257C . 1698-6180.
  11. Santos . Artai A. . Rodríguez-Barreiro . Iván . McLoughlin . Stephen . Pons . Denise . Valenzuela-Ríos . Jose I. . Diez . José B. . 2024 . Plant colonization of isolated palaeoecosystems: Palynology of a Middle Jurassic extinct volcanic island (Camarena, Teruel, eastern Spain) . Palaeogeography, Palaeoclimatology, Palaeoecology . 639 . 112081 . 10.1016/j.palaeo.2024.112081 . 2024PPP...63912081S . 0031-0182. free .
  12. Fernández-López . Sixto Rafael . 2011-09-01 . Taphonomic analysis and sequence stratigraphy of the Albarracinites beds (lower Bajocian, Iberian range, Spain). An example of shallow condensed section . Bulletin de la Société Géologique de France . 182 . 5 . 405–415 . 10.2113/gssgfbull.182.5.405 . 1777-5817.
  13. Hofmann . Christa-Ch. . Odgerel . Nyamsambuu . Seyfullah . Leyla J. . 2021 . The occurrence of pollen of Sciadopityaceae Luerss. through time . live . Fossil Imprint . 77 . 2 . 271–281 . 10.37520/fi.2021.019 . 245555379 . https://web.archive.org/web/20211227232247/https://www.biotaxa.org/AMNPSBHN/article/view/73112 . 27 December 2021 . 27 December 2021 . free.