Santana Group#Basin history

{{redirect|Santana Formation|the formation previously described as Santana Formation|Romualdo Formation}}

{{Infobox rockunit

| name = Santana Group

| image = Ipubi and Romualdo Formations - outcrop.jpg

| caption = Outcrop of the Santana Group; Ipubi & Romualdo Formations

| type = Group

| age = Aptian-Albian
~{{fossil range|115|108}}

| period = Albian

| prilithology = Mudstone, sandstone, shale, anhydrite

| otherlithology = Limestone, marl, siltstone

| namedfor = Santana do Cariri

| namedby =

| year_ts =

| region = Pernambuco
Piauí
Ceará

| country = Brazil

| coordinates = {{coord|5.6|S|64.3|W|display=inline,title}}

| paleocoordinates = {{coord|9.2|S|34.0|W|display=inline}}

| unitof =

| subunits = Romualdo, Ipubi & Crato Formations

| underlies = Araripina & Exu Formations

| overlies = Barbalha Formation

| thickness =

| extent = Araripe Basin

| area =

| map = Araripe Basin map - formations and resources.jpg

| map_caption = Extent of the Santana Group in blue

}}

The Santana Group is a geologic group, formerly included as the middle part of the Araripe Group, in the Araripe Basin of northeastern Brazil. The group comprises the Crato, Ipubi and Romualdo Formations and is dated to the Aptian to Albian stages of the Early Cretaceous. The formations of the group were deposited in a lacustrine to subtidal shallow marine environment in the Araripe rift basin.[https://paleobiodb.org/classic/displayStrata?geological_group=Santana&group_formation_member=Santana Santana Group] at Fossilworks.org

The Santana Group has provided a rich assemblage of fossils; flora, fish, arthropods insects, turtles, snakes, dinosaurs including Irritator, and pterosaurs such as Thalassodromeus. The stratigraphic units of the group contained several feathers of birds, among those the first record of Mesozoic birds in Brazil. The Romualdo and Crato Formations are renowned for their excellent conservation and designated Lagerstätten. In 2006, the Araripe Basin was designated a UNESCO Global Geopark.

Description

The Santana Group was formerly described as belonging to the Araripe Group.Scherer et al., 2013, p.28 The fossiliferous Santana Formation was previously defined as containing the Crato and Romualdo Members, but redefinition of the stratigraphy led to the establishment of the Santana Group, replacing the middle part of the Araripe Group and the former Crato, Ipubi and Romualdo members were elevated to separate formations.Assine, 1992, p.291Fabin et al., 2018, p.2050

= Basin history =

The tectono-sedimentary evolution of the Araripe Basin, located in the Borborema Geologic Province, encompasses four stages, with five tectonostratigraphic phases:Fabin et al., 2018, pp.2051-2052

1) Syneclise phase - Silurian to Devonian - characterized by tectonic quiescence in the Borborema Province. It is represented by the deposits of the Cariri Formation, that include medium to coarse-grained quartz sandstones, locally conglomeratic, deposited in large braided fluvial systems

2) Pre-rift phase - Tithonian - characterized by the mechanical subsidence due to lithosphere thinning that preceded the rift. It is represented by the Brejo Santo Formation, that comprises red shales and claystones, and the Missão Velha Formation, constituted by medium to coarse-grained quartz-feldspathic sandstones, locally conglomeratic, that contains entire trunks and fragments of silicified wood (Dadoxilon benderi) conifer

3) Rift phase - Berriasian to Hauterivian - characterized by increasing mechanical subsidence that created a system of grabens and half grabens. It is represented by the Abaiara Formation, that includes shales, siltstones, sandstones and conglomerates

4) Post-Rift I phase - Aptian to Albian - characterized by thermal subsidence. The lowermost unit Barbalha Formation, represents a fluviolacustrine phase and is composed of red and gray shales, siltstones and claystones.

The Santana Group was formed during this stage and comprises three stratigraphic units:

Crato Formation that is composed of six intervals of laminated limestones (C1 to C6), interbedded with calciferous siltstones and marls, and is very rich in fossils of vertebrate and invertebrate organisms
Ipubi Formation, that is mainly composed of organic-rich, black greenish bituminous shales, claystones and algal limestones that are interbedded with gypsum-anhydrite beds
Romualdo Formation, that represents a calciferous siliciclastic succession composed of fine to medium-grained sandstones, argillaceous siltstones, calciferous shales, and limestones, very rich in fossils. This formation recorded the marine proto-Atlantic incursion that involved the Araripe Basin, and other interior basins and created a large seaway throughout the Borborema Province during the Albian

5) Post-rift II phase - Albian to Cenomanian - characterized by a major sag phase, and is formed by two stratigraphic units:

Araripina Formation, that occurs in the western region of the basin and is composed by rhythmites and heterolithic layers of reddish, purplish and yellowish fine-grained sandstone and mudstone
Exu Formation, that comprises medium-to coarse grained sandstones, fine grained clayey sandstones and local conglomeratic beds

Fossil content

{{main|Romualdo Formation#Fossil content|Crato Formation#Fossil content}}

The upper and lower formations of the group are highly fossiliferous, with mainly insects, amphibians, fish,Fara et al., 2005, p.152Aparecida et al., 2015, p.25 and flora dominating the lower Crato Formation,Jorge de Lima et al., 2015, p.102 shrimps (Araripenaeus timidus),Pinheiro, 2014, p.4 and various genera of dinosaurs and fish in the Romualdo Formation.Weishampel et al., 2004, pp.563-570Cavalcanti Duque & Franca Barreto, 2018, p.9 A rich assemblage of pterosaur fossils are found in both formations,Elgin & Frey, 2011Martill, 2007, p.895 and the Ipubi Formation provided an indeterminate Pelomedusoides turtle.Ribeiro Oliveira et al., 2011, p.62

The Santana Group provided several feathers of birds, among those the first record of Mesozoic birds in Brazil.Prado et al., 2016, p.35

Gallery

Araripe Basin - depositional environments and sequence stratigraphy.jpg|Schematic development of the depositional environments

Araripe Basin - lake level cycles - Crato, Ipubi and Romualdo Formations.jpg|Lake level cyclicity

Santana Group - fossilized feathers and Dastilbe fossil.jpg|Fossil feathers and Dastilbe fossil

References

= Bibliography =

{{citation |last1=Aparecida dos Reis Polck |first1=Márcia |last2=Sardenberg Salgado de Carvalho |first2=Marise |last3=Miguel |first3=Raphael |last4=Gallo |first4=Valéria |year=2015 |title=Guia de identificação de peixes fósseis das Formações Crato e Santana da Bacia do Araripe |publisher=Serviço Geológico do Brasil (CPRM) |pages=1–74}}
{{citation |last=Assine |first=Mario L |year=1992 |title=Análise estratigráfica da Bacia do Araripe, Nordeste do Brasil |url=http://bjg.siteoficial.ws/1992/n.3/5.pdf |journal=Revista Brasileira de Geociências |volume=22 |issue=3 |pages=289–300 |doi=10.25249/0375-7536.1992289300 |accessdate=2018-10-05}}
{{citation |last1=Cavalcanti Duque |first1=Rudah Ruano |last2=Franca Barreto |first2=Alcina Magnólia |year=2018 |title=Novos Sítios Fossilíferos da Formação Romualdo, Cretáceo Inferior, Bacia do Araripe, Exu, Pernambuco, Nordeste do Brasil - New Fossiliferous Sites of the Romualdo Formation, Lower Cretaceous, Araripe Basin, Exu, Pernambuco, Northeast of Brazil |url=https://www.researchgate.net/publication/324900728 |journal=Anuário do Instituto de Geociências, UFRJ |volume=41 |pages=5–14 |doi=10.11137/2018_1_05_14 |accessdate=2018-10-06|doi-access=free }}
{{citation |last1=Elgin |first1=Ross A. |last2=Frey |first2=Eberhard |year=2011 |title=A new ornithocheirid, Barbosania gracilirostris gen. et sp. nov. (Pterosauria, Pterodactyloidea) from the Santana Formation (Cretaceous) of NE Brazil |url=https://dx.doi.org/10.1007/s13358-011-0017-4 |journal=Swiss Journal of Palaeontology |volume=130 |issue=2 |pages=259 |doi=10.1007/s13358-011-0017-4 |bibcode=2011SwJP..130..259E |accessdate=2018-10-06 }}{{Dead link|date=April 2023 |bot=InternetArchiveBot |fix-attempted=yes }}
{{citation |last1=Fabin |first1=Carlos E. |last2=Correia Filho |first2=Osvaldo J. |last3=Alencar |first3=Márcio L. |last4=Barbosa |first4=José A. |last5=de Miranda |first5=Tiago S. |last6=Neumann |first6=Virgínio H. |last7=Gomes |first7=Igor F. |last8=de Santana |first8=Felipe R. |year=2018 |title=Stratigraphic Relations of the Ipubi Formation: Siliciclastic-Evaporitic Succession of the Araripe Basin |url=http://www.scielo.br/pdf/aabc/v90n2s1/0001-3765-aabc-201820170526.pdf |journal=Anais da Academia Brasileira de Ciências |volume=90 |issue=2 suppl 1 |pages=2049–2071 |doi=10.1590/0001-3765201820170526 |pmid=29947671 |accessdate=2018-10-05}}
{{citation |last1=Fara |first1=Emmanuel |last2=Saraiva |first2=Antônio Á.F. |last3=Campos |first3=Díogenes de Almeida |last4=Moreira |first4=João K.R. |last5=de Carvalho Siebra |first5=Daniele |author6-link=Alexander Kellner |last6=Kellner |first6=Alexander W.A. |year=2005 |title=Controlled excavations in the Romualdo Member of the Santana Formation (Early Cretaceous, Araripe Basin, northeastern Brazil): stratigraphic, palaeoenvironmental and palaeoecological implications |url=http://biogeosciences.u-bourgogne.fr/documents/articles_pdf/2005_Fara_PalaeogeogrPalaeoclimatPalaeoecol.pdf |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=218 |issue=1–2 |pages=145–160 |doi=10.1016/j.palaeo.2004.12.012 |bibcode=2005PPP...218..145F |accessdate=2018-10-06}}
{{citation |last1=Jorge de Lima |first1=Flaviana |last2=Feitosa Saraiva |first2=Antonio Álamo |last3=Manso Sayão |first3=Juliana |year=2012 |title=Revisão da paleoflora das Formações Missão Velha, Crato e Romualdo, Bacia do Araripe, nordeste do Brasil |journal=Estudos Geológicos |volume=22 |issue=1 |pages=99–115}}
{{citation |last=Martill |first=D.M |year=2007 |title=The age of the Cretaceous Santana Formation fossil Konservat Lagerstätte of north-east Brazil: a historical review and an appraisal of the biochronostratigraphic utility of its palaeobiota |url=|doi=10.1016/j.cretres.2007.01.002 |journal=Cretaceous Research |volume=28 |issue=6 |pages=895–920 |bibcode=2007CrRes..28..895M }}
{{citation |last1=Neto |first1=João Adauto |last2=Mort |first2=Haydon |last3=Pereira |first3=Ricardo |last4=Barbosa |first4=José |last5=Neumann |first5=Virginio |last6=Vortisch |first6=Walter |last7=Filho |first7=Osvaldo J. C. |last8=Brandão |first8=Paulo de A. L. S. |last9=Pacheco |first9=José G. A. |year=2013 |title=Carbonaceous Shales in the Araripe Basin, NE Brazil: A Potential Shale Gas Reservoir |url=http://www.searchanddiscovery.com/pdfz/documents/2013/80309neto/ndx_neto.pdf.html |publisher=AAPG Annual Convention and Exhibition |pages=1–7 |accessdate=2018-10-05}}
{{citation |last1=Pinheiro |first1=Allysson P. |last2=Saraiva |first2=Antônio Á.F. |last3=Santana |first3=William |year=2014 |title=Shrimps from the Santana Group (Cretaceous: Albian): new species (Crustacea: Decapoda: Dendrobranchiata) and new record (Crustacea: Decapoda: Caridea) |url=http://www.scielo.br/pdf/aabc/2014nahead/0001-3765-aabc-0001-3765201420130338.pdf |journal=Anais da Academia Brasileira de Ciências |volume= |pages=1–8 |accessdate=2018-10-06 |archive-date=2017-08-24 |archive-url=https://web.archive.org/web/20170824213217/http://www.scielo.br/pdf/aabc/2014nahead/0001-3765-aabc-0001-3765201420130338.pdf |url-status=dead }}
{{citation |last1=Prado |first1=Gustavo M.E.M. |last2=Romero |first2=Guilherme Raffaelli |last3=Anelli |first3=Luiz Eduardo |year=2016 |title=New occurrences of fossilized feathers: systematics, taphonomy, and paleoecology of the Santana Formation of the Araripe Basin (Cretaceous), NE, Brazil |url=https://peerj.com/preprints/1170.pdf |journal=PeerJ |volume= |pages=1–49 |accessdate=2018-10-06 |archive-date=2018-10-06 |archive-url=https://web.archive.org/web/20181006200939/https://peerj.com/preprints/1170.pdf |url-status=dead }}
{{citation |last1=Ribeiro Oliveira |first1=Gustavo |last2=Feitosa Saraiva |first2=Antônio Álamo |last3=de Paula Silva |first3=Helder |last4=Ferreira Gomes de Andrade |first4=José Artur |author5-link=Alexander Kellner |last5=Kellner |first5=Alexander Wilhelm Armin |year=2011 |title=First turtle from the Ipubi Formation (Early Cretaceous), Santana Group, Araripe Basin, Brazil |journal=Revista Brasileira da Paleontologia |volume=14 |pages=61–66 |doi=10.4072/RBP.2011.1.06 |s2cid=32314916 }}
{{citation |last1=Scherer |first1=C.M.d.S. |last2=Jardim de Sá |first2=E.F. |last3=Córdoba |first3=V.C. |last4=Sousa |first4=D.d.C. |last5=Aquino |first5=M.M. |last6=Cardoso |first6=F.M.C. |year=2013 |title=Tectono-Stratigraphic evolution of the upper Jurassic-Neocomian rift succession, Araripe Basin, Northeast Brazil |url=https://estudogeral.sib.uc.pt/bitstream/10316/27124/1/Tectono-Stratigraphic%20evolution%20of%20the%20upper%20jurassic-neocomian%20rift%20succession.pdf |journal=Journal of South American Geosciences |volume= 49|pages=1–43 |doi=10.1016/j.jsames.2013.10.007 |bibcode=2014JSAES..49..106M |hdl=10316/27124 |accessdate=2018-10-05}}
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