Tuya

Key takeaways

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

Reference excerpt

A tuya is a flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet. They are rare worldwide, being confined to regions which were covered by glaciers and had active volcanism during the same period. As lava that erupts under a glacier cools very quickly and cannot travel far, it piles up into a steep-sided hill. If the eruption continues long enough, it either melts all the ice or emerges through the top of the ice and then creates normal-looking lava flows that make a flat cap on top of the hill. Discovering and dating the lava flows in a tuya has proven useful in reconstructing past glacial ice extents and thicknesses.

Formation

Tuyas are a type of subglacial volcano that consists of nearly horizontal beds of lava capping outward-dipping beds of fragmental volcanic rocks, and they often rise in isolation above a surrounding plateau. Tuyas are found in Iceland, British Columbia, the Santiam Pass region in Oregon, the Tyva Republic in eastern Russia, the Antarctic Peninsula and beneath the West Antarctic Ice Sheet. Tuyas in Iceland are sometimes called table mountains because of their flat tops. S. Holland, a geographer for the British Columbia government, described tuyas in the following way:

"They have a most interesting origin ... [they were] formed by volcanic eruptions which had been thawed through the Pleistocene ice-sheet by underlying volcanic heat. The lavas capping the mountains were extruded after the volcanoes were built above lake-level, and the outward-dipping beds were formed by the chilling of the lava when it reached the water's edge." Because they erupt under ice and water, tuyas have phreatomagmatic eruptions creating layers of breccia and hyaloclastite above pillow lavas. If the volcano breaches the surface of the glacier it will be topped by a subaerially erupted lava plateau.

Etymology The origin of the term comes from Tuya Butte, one of many tuyas in the area of the Tuya River and Tuya Range in far northern British Columbia, Canada. While still in graduate school in 1947, Canadian geologist Bill Mathews published a paper titled, "Tuyas, Flat-Topped Volcanoes in Northern British Columbia", in which he coined the term "tuya" to refer to these distinctive volcanic formations. Tuya Butte is a near-ideal specimen of the type, the first such landform analyzed in the geological literature, and this name has since become standard worldwide among volcanologists in referring to and writing about these formations. Tuya Mountains Provincial Park was recently established to protect this unusual landscape, which lies north of Tuya Lake and south of the Jennings River near the boundary with Yukon. Around the same time that Mathews published his paper, the Icelandic geologist Guðmundur Kjartansson had distinguished between "móberg" ridges and tuyas in Iceland and proposed the hypothesis that they were formed during subglacial and intraglacial eruptions. The term tuya may be derived from a Tahltan word.

Examples

See also Butte – Isolated hill with steep, often vertical sides and a small, relatively flat top Glaciovolcanism – Volcanism related to glacial phenomena Mesa – Elevated area of land with a flat top and sides, usually much wider than buttes Table Mountain (disambiguation)

References

Further reading Jakobsson, S. P.; Guðmundsson, M. T. (2008). "Subglacial and intraglacial volcanic formations in Iceland". Jökull: The Icelandic Journal of Earth Sciences. 58: 179–196. Mathews, W. H. (1 September 1947). "Tuyas, flat-topped volcanoes in northern British Columbia". American Journal of Science. 245 (9): 560–570. Bibcode:1947AmJS..245..560M. doi:10.2475/ajs.245.9.560. Mathews, W. H. (1 November 1951). "The Table, a flat-topped volcano in southern British Columbia". American Journal of Science. 249 (11): 830–841. Bibcode:1951AmJS..249..830M. doi:10.2475/ajs.249.11.830. Moore, James G.; Lewis C. Calk (May 1991). "Degassing and differentiation in subglacial volcanoes, Iceland". Journal of Volcanology and Geothermal Research. 46 (1–2): 157–180. Bibcode:1991JVGR...46..157M. doi:10.1016/0377-0273(91)90081-A.

External links Canadian Mountain Encyclopedia entry on Kawdy Plateau Canadian Mountain Encyclopedia entry on Tuya Butte

Illustrations

Worked examples

Example 1 — a first encounter with Tuya

Start with the simplest possible case. Write down what Tuya 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 Tuya 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 Tuya 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 Tuya

In research: Tuya 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 Tuya 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: Tuya is common in secondary-school and first-year university syllabi. It links to neighbouring topics Tuyas, Volcanoes, so understanding it makes those chapters shorter.
In everyday life: Look for Tuya 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.

How to study Tuya in 20 minutes

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

Frequently asked questions

What is Tuya in simple terms?

A tuya is a flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet. They are rare worldwide, being confined to regions which were covered by glaciers and had active volcanism during the same period.

Why does Tuya 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 Tuya?

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 Tuya.