earth science

Romualdo Formation

Romualdo Formation is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Romualdo Formation rather than just read about it. In short: The Romualdo Formation is a geologic Konservat-Lagerstätte in northeastern Brazil's Araripe Basin where the states of Pernambuco, Piauí and Ceará come together. The geological formation, previously designated as the Romualdo Member of the Santana Formation, named after the village of Santana do Cariri, lies at the base of the Araripe Plateau.

Key takeaways

Romualdo Formation belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Romualdo Formation to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Romualdo Formation from memory before moving on to harder problems.

Reference excerpt

The Romualdo Formation is a geologic Konservat-Lagerstätte in northeastern Brazil's Araripe Basin where the states of Pernambuco, Piauí and Ceará come together. The geological formation, previously designated as the Romualdo Member of the Santana Formation, named after the village of Santana do Cariri, lies at the base of the Araripe Plateau. It was discovered by Johann Baptist von Spix in 1819. The strata were deposited during the Aptian stage of the Early Cretaceous in a lacustrine rift basin with shallow marine incursions of the proto-Atlantic. At that time, the South Atlantic was opening up in a long narrow shallow sea. The Romualdo Formation earns the designation of Lagerstätte due to an exceedingly well preserved and diverse fossil faunal assemblage. Some 25 species of fossil fishes are often found with stomach contents preserved, enabling paleontologists to study predator–prey relationships in this ecosystem. There are also fine examples of pterosaurs, reptiles and invertebrates, and crocodylomorphs. Even dinosaurs are represented (Spinosauridae, Tyrannosauroidea, Compsognathidae). The unusual taphonomy of the site resulted in limestone accretions that formed nodules around dead organisms, preserving even soft parts of their anatomy. In preservation, the nodules are etched away with acid, and the fossils often prepared by the transfer technique. Local mining activities for cement and construction damage the sites. Trade in illegally collected fossils has sprung up from the decade of 1970, driven by the remarkable state of preservation and beauty of these fossils and amounting to a considerable local industry. An urgent preservation program is being called for by paleontologists. In addition, the weathering of Romualdo Formation rocks has contributed soil conditions unlike elsewhere in the region. The Araripe manakin (Antilophia bokermanni) is a very rare bird that was discovered only in the late 20th century; it is not known from anywhere outside the characteristic forest that grows on the Chapada do Araripe soils formed ultimately from Romualdo Formation rocks.

Geology and dating

The Crato Formation was previously considered the lowest member of the then Santana Formation, but has been elevated to a formal formation. The Crato Formation is the product of a single phase, where complicated sequence of sediment strata reflect changeable conditions in the opening sea. The age of the Romualdo Formation, formerly known as the Romualdo Member of the Santana Formation, has been controversial, though most workers have agreed that it lies on or near the Aptian–Albian boundary, about 112 million years ago. Nevertheless, a Cenomanian age cannot be ruled out. The extent of the Crato unit and its relationship to the Romualdo Formation had long been ill-defined. It was not until a 2007 volume on the unit by Martill, Bechly and Loveridge that the Crato Formation was given a formal type locality, and was formally made a distinct formation separate from the Romualdo Formation, which is about 10 Ma younger.

Fossil content

Archosaurs Indeterminate remains of non-avian theropods, avialans, ornithischians, and possibly oviraptorosaurs have been found in Ceara state, Brazil. The oviraptorosaurian remains have been re-identified as megaraptoran fossils.

Dinosaurs

Crocodylomorphs

Pterosaurs

Turtles

Fish

See also

References

Bibliography Cavalcanti Duque, Rudah Ruano; Franca Barreto, Alcina Magnólia (2018). "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". Anuário do Instituto de Geociências. 41: 5–14. doi:10.11137/2018_1_05_14. Retrieved 6 October 2018. Elgin, Ross A.; Frey, Eberhard (20 April 2011). "A new ornithocheirid, Barbosania gracilirostris gen. et sp. nov. (Pterosauria, Pterodactyloidea) from the Santana Formation (Cretaceous) of NE Brazil". Swiss Journal of Palaeontology. 130 (2): 259. Bibcode:2011SwJP..130..259E. doi:10.1007/s13358-011-0017-4. ISSN 1664-2384. S2CID 89178816. Fabin, Carlos E.; Correia Filho, Osvaldo J.; Alencar, Márcio L.; Barbosa, José A.; de Miranda, Tiago S.; Neumann, Virgínio H.; Gomes, Igor F.; de Santana, Felipe R. (2018). "Stratigraphic Relations of the Ipubi Formation: Siliciclastic-Evaporitic Succession of the Araripe Basin" (PDF). Anais da Academia Brasileira de Ciências. 90 (2 suppl 1): 2049–2071. doi:10.1590/0001-3765201820170526. PMID 29947671. Retrieved 5 October 2018. Fara, Emmanuel; Saraiva, Antônio Á.F.; Campos, Díogenes de Almeida; Moreira, João K.R.; de Carvalho Siebra, Daniele; Kellner, Alexander W.A. (2005). "Controlled excavations in the Romualdo Member of the Santana Formation (Early Cretaceous, Araripe Basin, northeastern Brazil): stratigraphic, palaeoenvironmental and palaeoecological implications" (PDF). Palaeogeography, Palaeoclimatology, Palaeoecology. 218 (1–2): 145–160. Bibcode:2005PPP...218..145F. doi:10.1016/j.palaeo.2004.12.012. Retrieved 6 October 2018. Maisey, J.G.; Rutzky, I.; Blum, S.; Elvers, W. (1991). Laboratory Preparation Techniques. In Maisey, j:G. (ed): Santana Fossils: An Illustrated Atlas. Tfh Publications Inc. pp. 99–103. ISBN 0866225498. Martill, David M.; Bechly, Günter; Loveridge, Robert F. (2007). The Crato Fossil Beds of Brazil: Window into an Ancient World. Cambridge University Press. p. 236. ISBN 978-1-139-46776-6. Retrieved 6 October 2018. Martill, D.M. (2007). "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". Cretaceous Research. 28 (6): 895–920. Bibcode:2007CrRes..28..895M. doi:10.1016/j.cretres.2007.01.002. Retrieved 6 October 2018. Weishampel, David B.; Barrett, Paul M.; Coria, Rodolfo A.; Loeuff, Jean Le; Xu, Xing; Zhao, Xijin; Sahni, Ashok; Gomani, Elizabeth M. P.; Noto, Christopher R. (2004). Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.). Dinosaur distribution (Early Cretaceous, South America): The Dinosauria. Berkeley: University of California Press. pp. 563–570. ISBN 0-520-24209-2.{{cite book}}: CS1 maint: publisher location (link)

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Illustrations

Worked examples

Example 1 — a first encounter with Romualdo Formation

Start with the simplest possible case. Write down what Romualdo Formation claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Romualdo Formation before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Romualdo Formation ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Romualdo Formation

In research: Romualdo Formation appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Romualdo Formation in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Romualdo Formation is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cretaceous Brazil, Cretaceous paleontological sites of South America, Deltaic deposits, so understanding it makes those chapters shorter.
In everyday life: Look for Romualdo Formation outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Romualdo Formation in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Romualdo Formation means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
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Frequently asked questions

What is Romualdo Formation in simple terms?

Why does Romualdo Formation matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Romualdo Formation?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Romualdo Formation.