biology

La Meseta Formation

La Meseta Formation is a biology 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 Meseta Formation rather than just read about it. In short: The La Meseta Formation is a sedimentary sequence deposited during much of the Paleogene on Seymour Island off the coast of the Antarctic Peninsula. It is noted for its fossils, which include both marine organisms and the only terrestrial vertebrate fossils from the Cenozoic of Antarctica.

Key takeaways

La Meseta Formation belongs to biology; place it in that map before memorising details.
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Connect La Meseta Formation to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of La Meseta Formation from memory before moving on to harder problems.

Reference excerpt

The La Meseta Formation is a sedimentary sequence deposited during much of the Paleogene on Seymour Island off the coast of the Antarctic Peninsula. It is noted for its fossils, which include both marine organisms and the only terrestrial vertebrate fossils from the Cenozoic of Antarctica. In some treatments, the La Meseta Formation is restricted to just the older Thanetian to Lutetian-aged strata, with the younger Bartonian to Rupelian strata treated as the overlying Submeseta Formation. However, other papers instead treat the Submeseta Formation as an allomember of the La Meseta Formation.

Description La Meseta Formation lies unconformably on the Cretaceous López de Bertodano Formation. It is an approximately 557 metres (1,827 ft) thick sequence of poorly consolidated sandstones and siltstones. The depositional environment was probably coastal, deltaic or estuarine in character. The top of the sequence is an erosional unconformity to Pleistocene glacial gravels. La Meseta Formation is one of the sequences that make up the fill of the Late Jurassic to Paleogene James Ross Basin.

Paleoenvironment The terrestrial environment surrounding the deposition area is thought to have been a temperate polar forest, including podocarp and araucarian conifers, as well as Nothofagus. Most of the fossilized woods and flowers discovered on Seymour Islands consist of extinct species of conifer trees and lilies during warm climate.

Paleobiota La Meseta Formation is extremely rich in fossils. Among mammals, the meridiungulata Antarctodon and Trigonostylops have been found in the formation. as well as marsupial Derorhynchidae, Microbiotheria, and polydolopimorphia. It is famous for its penguin fossils, for example the two genera Archaeospheniscus and Palaeeudyptes. Other bird fossils include Dasornis, a genus of pseudotooth birds. There is also an abundance of trace fossils. Diplocraterion, Helminthopsis, Muensteria, Oichnus, Ophiomorpha, Skolithos, Teredolites and Zapfella have been described. Over 35 species and 26 families of fish, which includes sharks, have been described from the Ypresian Cucullaea bed.

Mammals

Meriduingulata Astrapotheria

Litopterna

Cetaceans

Metatherians Derorhynchidae

Microbiotheria

Polydolopimorphia

Other mammals

Birds

Sphenisciformes

Other birds

Reptiles

Amphibians

Cartilaginous fish

Chimaeras

Sharks

Rays

Ray-finned fish

Cephalopods

Plants

See also

List of fossiliferous stratigraphic units in Antarctica

References

Further reading R. A. Askin. 1997. Eocene-?Earliest Oligocene terrestrial palynology of Seymour Island, Antarctica. : 993-996. The Antarctic Region: Geological Evolution and Processes 993-996 M. A. Bitner. 1991. A supposedly new brachiopod from the Paleogene of Seymour Island, West Antarctica. Polish Polar Research 12(2):243-246 D. B. Blake; R. B. Aronson (1998). "Eocene stelleroids (Echinodermata) at Seymour Island, Antarctic Peninsula". Journal of Paleontology. 72 (2): 339–353. Bibcode:1998JPal...72..339B. doi:10.1017/S0022336000036325. M. Bond, M. A. Reguero, S. F. Vizcaino and S. A. Marenssi. 2006. A new 'South American ungulate' (Mammalia: Litopterna) from the Eocene of the Antarctic Peninsula. Geological Society, London, Special Publications 258:163-176 J. A. Case. 1988. Paleogene floras from Seymour Island, Antarctic Peninsula. Geology and Paleontology of Seymour Island Antarctic Peninsula 523-540 M. M. Cenizo. 2012. Review of the putative Phorusrhacidae from the Cretaceous and Paleogene of Antarctica: new records of ratites and pelagornithid birds. Polish Polar Research 33(3):225-244 A. L. Cione, M. de las Mercedes Azpelicueta, and D. R. Bellwood. 1995. An oplegnathid fish from the Eocene of Antarctica. Palaeontology 37(4):931-940 A. L. Cione and M. A. Reguero. 1994. New records of the sharks Isurus and Hexanchus from the Eocene of Seymour Island, Antarctica. Proceedings of the Geologists' Association 105:1-14 J. Kriwet (2005). "Additions to the Eocene Selachian Fauna of Antarctica with Comments on Antarctic Selachian Diversity". Journal of Vertebrate Paleontology. 25 (1): 1–7. doi:10.1671/0272-4634(2005)025[0001:ATTESF]2.0.CO;2. S. A. Marenssi, M. A. Regeuro, S. N. Santillana and S. F. Vizcaino. 1994. Eocene land mammals from Seymour Island, Antarctica: palaeobiogeographical implications. 6(1):3-15 I. Poole, A. M. W. Mennega, and D. J. Cantrill. 2003. Valdivian ecosystems in the Late Cretaceous and Early Tertiary of Antarctica: further evidence from myrtaceous and eucryphiaceous fossil wood. Review of Palaeobotany and Palynology 124:9-27 R. R. Pujana, S. N. Santillana, and S. A. Marenssi. 2014. Conifer fossil woods from the La Meseta Formation (Eocene of Western Antarctica): Evidence of Podocarpaceae-dominated forests. Review of Palaeobotany and Palynology (200)122-137 S. F. Vizcaino, M. A. Reguero, S. A. Marenssi and S. N. Santillana. 1997. New land mammal-bearing localities from the Eocene La Meseta Formation, Seymour Island, Antarctica. The Antarctic Region: Geological Evolution and Processes 997-1000

Illustrations

Worked examples

Example 1 — a first encounter with La Meseta Formation

Start with the simplest possible case. Write down what La Meseta Formation claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Meseta 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 Meseta 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 Meseta Formation

In research: La Meseta Formation appears in biology 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 Meseta 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 Meseta Formation is common in secondary-school and first-year university syllabi. It links to neighbouring topics Conglomerate formations, Deltaic deposits, Geologic formations of Antarctica, so understanding it makes those chapters shorter.
In everyday life: Look for La Meseta 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 Meseta Formation in 20 minutes

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

Frequently asked questions

What is La Meseta Formation in simple terms?

Why does La Meseta Formation matter?

Because it connects several biology 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 Meseta 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 Meseta Formation.