science

Laschamp event

Laschamp event is a 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 Laschamp event rather than just read about it. In short: The Laschamp or Laschamps event, also termed the Adams event, was a geomagnetic excursion (a short reversal of the Earth's magnetic field) that occurred between 42,200 and 41,500 years ago, during the Last Glacial Period. It was discovered from geomagnetic anomalies found in the Laschamps and Olby lava flows near Clermont-Ferrand, France in the 1960s.

Key takeaways

Laschamp event belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Laschamp event to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Laschamp event from memory before moving on to harder problems.

Reference excerpt

The Laschamp or Laschamps event, also termed the Adams event, was a geomagnetic excursion (a short reversal of the Earth's magnetic field) that occurred between 42,200 and 41,500 years ago, during the Last Glacial Period. It was discovered from geomagnetic anomalies found in the Laschamps and Olby lava flows near Clermont-Ferrand, France in the 1960s. The Laschamp event was the first known geomagnetic excursion and remains the most thoroughly studied among the known geomagnetic excursions. It is named after the village of Laschamps, part of the commune of Saint-Genès-Champanelle in France.

Background and effects Since its discovery, the magnetic excursion has been demonstrated in geological archives from many parts of the world. The transition from the normal field to the reversed field lasted approximately 250 years, while the magnetic field remained reversed for approximately 440 years. During the transition, Earth's magnetic field declined to a minimum of 5% of its current strength, and was at about 25% of its current strength when fully reversed. This reduction in geomagnetic field strength resulted in more cosmic rays reaching the Earth, causing greater production of the cosmogenic isotopes beryllium-10 and carbon-14, a decrease in atmospheric ozone, and changes in atmospheric circulation. This loss of the geomagnetic shield has been claimed to have contributed to the extinction of Australian megafauna, the extinction of the Neanderthals and the appearance of cave art. However, the lack of corroborating evidence of a causal link between the Laschamp event and population bottlenecks of many megafauna species, and the relatively moderate radio-isotopic changes during the event, have cast significant doubt on the real impact of the Laschamp event on global environmental changes. Because it occurred approximately 42,000 years ago, the period has been termed the Adams Event or Adams Transitional Geomagnetic Event, a tribute to science fiction writer Douglas Adams, who wrote in The Hitchhiker's Guide to the Galaxy that "42" was the answer to life, the universe and everything.

Research The Australian Research Council funded research to analyze a fossilized kauri tree found in New Zealand in 2019. Radiocarbon dating revealed that the tree was alive from 42,500–41,000 years ago, within the timeframe of the event.

See also Late Pleistocene extinctions Solar cycle Solar cycle 1 Timeline of prehistory#Upper Paleolithic

External links A sounded visualisation of the Laschamp event from ESA.

Notes

References

Worked examples

Example 1 — a first encounter with Laschamp event

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

In research: Laschamp event appears in 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 Laschamp event 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: Laschamp event is common in secondary-school and first-year university syllabi. It links to neighbouring topics Geomagnetic reversal, Late Pleistocene, so understanding it makes those chapters shorter.
In everyday life: Look for Laschamp event 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 Laschamp event in 20 minutes

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

Frequently asked questions

What is Laschamp event in simple terms?

Why does Laschamp event matter?

Because it connects several 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 Laschamp event?

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 Laschamp event.