earth science

La Amarga Formation

La Amarga 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 La Amarga Formation rather than just read about it. In short: The La Amarga Formation is a geologic formation with outcrops in the Argentine provinces of Río Negro, Neuquén, and Mendoza. It is the oldest Cretaceous terrestrial formation in the Neuquén Basin.

Key takeaways

La Amarga 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 La Amarga Formation to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of La Amarga Formation from memory before moving on to harder problems.

Reference excerpt

The La Amarga Formation is a geologic formation with outcrops in the Argentine provinces of Río Negro, Neuquén, and Mendoza. It is the oldest Cretaceous terrestrial formation in the Neuquén Basin. The type locality is La Amarga Arroyo and China Muerta Hill. The La Amarga Formation unconformably overlies the marine Agrio Formation of the Mendoza Group. It is in turn overlain by the Lohan Cura Formation, separated by another unconformity.

Composition There are three members within the La Amarga Formation.

The oldest is the Puesto Antigual Member, which is approximately 28.9 metres (95 ft) thick and consists mainly of sandstone deposited in the channels of a braided river system. Paleosols, or soil deposits, are well-developed. The Bañados de Caichigüe Member is the next highest, approximately 20.9 metres (69 ft) thick. Alternating limestones, shales, and siltstones make up this member, indicating a lacustrine (lake) environment. Youngest and thickest is the Piedra Parada Member, approximately 109.4 metres (359 ft) thick in some sections. This member consists of alternating sandstones and siltstones from an ancient alluvial plain, with some swamp and paleosol deposits.

Fossil content Most of the tetrapod fossils found in the La Amarga come from the Puesto Antigual Member.

Dinosaurs

Other tetrapods

See also List of dinosaur-bearing rock formations

References

Bibliography Galton, Peter M.; Carpenter, Kenneth (2016). "The plated dinosaur Stegosaurus longispinus Gilmore, 1914 (Dinosauria: Ornithischia; Upper Jurassic, western USA), type species of Alcovasaurus n. gen". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 279 (2): 185–208. doi:10.1127/njgpa/2016/0551. Pereda Suberbiola, Xabier; Galton, Peter M.; Mallison, Heinrich; Novas, Fernando (2012). "A plated dinosaur (Ornithischia, Stegosauria) from the Early Cretaceous of Argentina, South America: an evaluation". Alcheringa: An Australasian Journal of Palaeontology. 37 (1): 1–14. doi:10.1080/03115518.2012.702531 Carrano, M.T.; Loewen, M.A.; Sertic, J.J.W. (2011). "New Materials of Masiakasaurus knopfleri Sampson, Carrano, and Forster, 2001, and Implications for the Morphology of the Noasauridae (Theropoda: Ceratosauria)". Smithsonian Contributions to Paleobiology. 95 (95): 1–53. doi:10.5479/si.00810266.95.1. Weishampel, David B.; Dodson, Peter; Osmólska, Halszka, eds. (2004). The Dinosauria, 2nd edition. Berkeley: University of California Press. pp. 1–880. ISBN 978-0-520-94143-4. Retrieved 2019-02-21.{{cite book}}: CS1 maint: publisher location (link) ISBN 0-520-24209-2 Montanelli, S. B (1987). "Presencia de Pterosauria (Reptilia) en la Formación La Amarga (Hauteriviano-Barremiano), Neuquén, Argentina". Ameghiniana. 24: 109–113. Musacchio, E (1970). "Ostrácodos de la superfamilias Cytheraceae y Darwinulaceae de la Formación La Amarga (Cretácico inferior), provincia del Neuquén, Argentina". Ameghiniana. 7: 301–318.

Further reading Apesteguía, Sebastián (2007). "The sauropod diversity of the La Amarga Formation (Barremian), Neuquén (Argentina)". Gondwana Research. 12 (4): 533–546. Bibcode:2007GondR..12..533A. doi:10.1016/j.gr.2007.04.007. Retrieved 2016-02-16. Leanza, H.A.; Apesteguia, S.; Novas, F.E.; De la Fuente, M.S. (2004). "Cretaceous terrestrial beds from the Neuquén Basin (Argentina) and their tetrapod assemblages". Cretaceous Research. 25 (1): 61–87. Bibcode:2004CrRes..25...61L. doi:10.1016/j.cretres.2003.10.005. Retrieved 2019-02-16.

Illustrations

Worked examples

Example 1 — a first encounter with La Amarga Formation

Start with the simplest possible case. Write down what La Amarga 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 La Amarga 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 La Amarga 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 La Amarga Formation

In research: La Amarga 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 La Amarga 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: La Amarga Formation is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alluvial deposits, Cretaceous Argentina, Fluvial deposits, so understanding it makes those chapters shorter.
In everyday life: Look for La Amarga 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 La Amarga Formation in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what La Amarga 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.
Explain La Amarga Formation out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is La Amarga Formation in simple terms?

The La Amarga Formation is a geologic formation with outcrops in the Argentine provinces of Río Negro, Neuquén, and Mendoza. It is the oldest Cretaceous terrestrial formation in the Neuquén Basin.

Why does La Amarga 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 La Amarga 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 La Amarga Formation.