earth science

Mealla Formation

Mealla 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 Mealla Formation rather than just read about it. In short: The Mealla Formation is a geological formation of the Santa Bárbara Subgroup, part of the Salta Group in the Salta Basin in northwestern Argentina whose strata date back to the Middle to Late Paleocene of the Paleogene. Description The Mealla Formation comprises sandstones ranging upward to siltstones with a basal conglomerate bed.

Key takeaways

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

Reference excerpt

The Mealla Formation is a geological formation of the Santa Bárbara Subgroup, part of the Salta Group in the Salta Basin in northwestern Argentina whose strata date back to the Middle to Late Paleocene of the Paleogene.

Description The Mealla Formation comprises sandstones ranging upward to siltstones with a basal conglomerate bed. The formation unconformably overlies the Yacoraite Formation and is overlain by the Thanetian Maíz Gordo Formation. The thickness of the formation ranges from 100 to 150 metres (330 to 490 ft). The formation is the lowermost unit in the Santa Bárbara Subgroup, representing the post-rift phase of the Salta Basin. The Mealla Formation was deposited in a fluvial environment. Other parts of the formation contain freshwater stromatolites, interpreted as deposited in a shallow lacustrine environment. The basal conglomerate is 3.5 metres (11 ft) thick, matrix-supported with 80% of the clasts coming from quartzites from the Cambrian Mesón Group, with the remainder of the clasts provenanced by the Precambrian Puncoviscana Formation and the quartzarenites of the Santa Victoria Group. The conglomeratic section also contains paleosols. The pollen analysis performed by Quattrocchio et al. in 1997 indicated a phase of higher aridity during the deposition of the Mealla Formation. The formation was initially described as Riochican, and later as Itaboraian, but after the redefinition of the Itaboraí Formation to Early Eocene, the Mealla Formation is Peligran to Riochican in age. The Mealla Formation is correlated with the Río Loro Formation that crops out in the Sierras Pampeanas to the southeast of the Salta Basin.

Fossil content The following fossils were reported from the formation:

Mammals Notoungulata Archaeogaia macachaae Notoungulata - Henricosborniidae Simpsonotus major S. praecursor Reptiles Pelomedusidae indet. Sebecus ayrampu Snakes Powellophis andina Pollen Aquifoliaceae Gemmatricolpites subsphaericus Haloragaceae Myriophyllumpollenites sp. Oenotheraceae Corsinipollenites menendezii Pandanaceae Pandaniidites texus Salicaceae Rousea patagonica Ulmaceae (Phyllostylon) Verrustephanoporites simplex

See also South American land mammal ages Itaboraí Formation

References

Bibliography Narváez, Paula Liliana (2009), Palinoestratigrafía, paleoambientes y cambios climáticos durante el Cretácico final y Paleógeno de la Cuenca del Grupo Salta, República Argentina (PhD thesis) (PDF), Universidad Nacional de Salta, pp. 1–229, retrieved 2020-06-13 Sánchez, María Cristina; Marquillas, Rosa A. (2010), "Facies y ambientes del Grupo Salta (Cretácico-Paleógeno) en Tumbaya, Quebrada de Humahuaca, Provincia de Jujuy" (PDF), Revista de la Asociación Geológica Argentina, 67: 383–391, retrieved 2020-06-13 Quattrocchio, M.E.; Volkheimer, W.; del Papa, C. (1997), "Palynology and paleoenvironment of the "Faja Gris" Mealla Formation (Salta Group) at Garabatal creek (NW Argentina)", Palynology, 21 (1): 231–247, Bibcode:1997Paly...21..231Q, doi:10.1080/01916122.1997.9989498 Pascual, R.; Vucetich, M.G.; Fernández, J. (1978), "Los primeros mamiferos (notoungulata, henricosborniidae) de la Formacion Mealla (Grupo Salta, subgrupo Santa Barbara): sus implicancias filogeneticas, taxonomicas y cronologicas", Ameghiniana, 15: 366–390

Worked examples

Example 1 — a first encounter with Mealla Formation

Start with the simplest possible case. Write down what Mealla 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 Mealla 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 Mealla 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 Mealla Formation

In research: Mealla 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 Mealla 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: Mealla Formation is common in secondary-school and first-year university syllabi. It links to neighbouring topics Conglomerate formations of Argentina, Fluvial deposits, Fossiliferous stratigraphic units of South America, so understanding it makes those chapters shorter.
In everyday life: Look for Mealla 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 Mealla Formation in 20 minutes

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

Frequently asked questions

What is Mealla Formation in simple terms?

Why does Mealla 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 Mealla 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 Mealla Formation.