earth science

Paso Flores Formation

Paso Flores 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 Paso Flores Formation rather than just read about it. In short: The Paso Flores Formation is a latest Late Triassic (Rhaetian) geologic formation in the Neuquén Basin of Neuquén Province in northwestern Patagonia, Argentina. The brown to red-stained conglomerates, sandstones and shales of the formation represent the youngest and only latest Triassic sedimentary unit in the country, overlying basement.

Key takeaways

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

Reference excerpt

The Paso Flores Formation is a latest Late Triassic (Rhaetian) geologic formation in the Neuquén Basin of Neuquén Province in northwestern Patagonia, Argentina. The brown to red-stained conglomerates, sandstones and shales of the formation represent the youngest and only latest Triassic sedimentary unit in the country, overlying basement. The formation has provided a rich fossil flora of various groups, preserved in leaves and fossil wood in the finer lithologies in the Paso Flores Formation. The fossil flora is representative of the ecosystem of the latest Triassic, preceding the Triassic-Jurassic extinction event.

Description The formation was first defined by Fossa Mancini in 1937 as the Formación Continental de Paso Flores. Later, Frenguelli (1948) called the formation Estratos de Paso Flores ("Paso Flores Beds") and Galli (1954, 1969) described it as Serie de Paso Flores. Finally, the formation was described as Paso Flores Formation (Nullo, 1979, González Díaz, 1982, Spalletti et al., 1988). based on a type section exposed along the Limay River in the southern Neuquén Basin. The Paso Flores Formation comprises conglomerates, sandstones and shales.

Extent

The formation crops out in its largest extent around the Limay River and the Ranquel-Huao hill and north of Estancia Corral de Piedra. Other outcrops are found northeast of Estancia Collón Curá y on the right banks of the Collón Curá River and in the cañadones of Pancho and El Pedregoso. The type section is found in the eponymous Paso Flores, on the left (western) banks of the Limay River and around Cerro Mariana. The national roads 40 and 237 cross-cut the formation.

Stratigraphy Separated by a marked unconformity, the formation overlies the Paleozoic crystalline basement of the Cushamen Formation. The Paso Flores Formation is unconformably overlain by the Jurassic Sañicó and Nestares Formations, and Neogene Collón Curá, Caleufú and Cerro Petiso Formations and by alluvium. The Sañicó Lineament puts the Paso Flores Formation in contact with Famatinian basement.

Age and correlation

González Díaz (1982) assigned a Late Triassic age to the formation, based on a paleofloristic analysis of the Paso Flores Formation executed west of the Collón Curá River. Ganuza et al. (1995) realized a paleobotanical study at Cañadón de Pancho and reached the same conclusion of a Late Triassic age. Zavattieri (1997) observed that the macro- and microflora indicated a Rhaetian age. Several taxa known from the Jurassic are present as well as typical Triassic taxa as Telemachus elongatus and Pagiophyllum. The formation is the only fossiliferous latest Triassic formation. The Paso Flores Formation is correlated with the Garamilla, Los Menucos and Sierra Colorada Formations elsewhere in Argentina. Dictyophyllum tenuifolium, whose type locality is the Paso Flores Formation, is also found in the Ladinian Cortaderita Formation of San Juan Province.

Lithology The Paso Flores Formation is a terrestrial unit with a high fossil content, composed of conglomerates, conglomeratic sandstones and lightbrown sandstones and shales with iron staining. The thickness of the formation varies from 30 metres (98 ft) in the Ranquel Huao hills, 90 metres (300 ft) in the Cañadón de Pancho and according to Frenguelli (1948) and Spalletti et al.(1988), 263 metres (863 ft) in Estancia Paso Flores and Cerro Mariana. The well-consolidated conglomerates comprise rounded polymict granitic and volcanic clasts of up to 20 centimetres (7.9 in) in a sandy matrix. Intercalated in the conglomerates are lenses of fine-to-medium grained sandstones and shales preserving fossil leaves and fossilized treetrunks.

Fossil content

The Paso Flores has provided a variety of flora fossils, reported from three outcrops: In 2003, more specific descriptions were carried out of Cladophlebis grahami, C. denticulata, Dictyophyllum chihuiuensis, D. tenuiserratum and D. rothi, Rhexoxylon brunoi, Dicroidium crassum, D. odontopteroides, D. lancifolium, Xylopteris argentina and X. elongata. Abundant other flora are Scleropteris grandis, Linguifolium arctum, L. lilleanum, L. tenisonwoodsii and L. steinmannii, Cycadocarpidium and Heidiphyllum, Telemachus and Protocircoporoxylon marianaensis. In 2017, several flora were described; Lutanthus ornatus, Rissikistrobus plenus, Rissikistrobus reductus, Rissikia media, Umkomasia sp., Sphenobaiera argentinae, Pseudoctenis spatulata, Taeniopteris crassinervis and Yabeiella brackebuschiana. Additionally, Baiera triassica, in replacement of the homonymous species previously identified in Argentina as Baiera taeniata, Ginkgo taeniata and Sphenobaiera taeniata, were described as well as new species previously described from other locations than the analyzed Quemquemtreu area of the Cañadón Pancho locality. These species are: Asterotheca rigbyana, Marattiopsis muensteri, Cladophlebis kurtzii, C. indica, Dictyophyllum (Dictyophyllum) tenuifolium, Goeppertella stipanicicii, Dicroidium incisum, D. odontopteroides, D. lancifolium, Pachydermophyllum praecordillerae, Heidiphyllum elongatum, Baiera furcata, Sphenobaiera robusta, Pseudoctenis carteriana and P. falconeriana.

Paso Flores PGAP 2402 - Spalletti et al. (1988) Pinopsida Araucarioxylon sp. Araucarites sp. Peltaspermopsida Dicroidium sp. Xylopteris sp. Peltaspermopsida Sphenobaiera sp. Ginkgoopsida Baiera sp. Czekanowskia sp. Ginkgoites sp. Pinopsida Podozamites sp. Desmiophyllum sp. Pseudoctenis sp. Polypodiopsida Coniopteris sp. Dictyophyllum sp. Polypodiopsida Cladophlebis sp.

Cañadón del Ranquel Huao PGAP 2403 - idem Peltaspermopsida Dicroidium sp. Ginkgoopsida Baiera sp. Pinopsida Asterotheca sp. Kurtziana sp. Pachydermophyllum sp. Podozamites sp. Pseudoctenis sp. Polypodiopsida Cladophlebis sp. Coniopteris sp. Dictyophyllum sp. Thaumatopteris sp.

Cañadón de Pancho PGAP 2404 - Artabe et al. (1994) Ginkgoopsida Cycadocarpidium sp. Czekanowskia sp. Johnstonia sp. Nilsonia sp. Pseudoctenis sp. Scleropteris sp. Taeniopteris sp. Zuberia sp. Peltaspermopsida Dicroidium sp. Heidiphyllum sp. Linguifolium sp. Sphenobaiera sp. Xylopteris sp. Additionally, several spores and pollen were described from the formation by Zavattieri and Mego in 2008:

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Paso Flores Formation

Start with the simplest possible case. Write down what Paso Flores 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 Paso Flores 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 Paso Flores 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 Paso Flores Formation

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

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

Frequently asked questions

What is Paso Flores Formation in simple terms?

Why does Paso Flores 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 Paso Flores 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 Paso Flores Formation.