guide fossil
- noun
- UK
:
fósil guía
- Scientists use guide fossils to correlate the ages of rocks in different locations around the world.
Examples
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The discovery of a guide fossil helped geologists accurately date the sedimentary rock layer.
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Trilobites are often cited as a classic example of a guide fossil in Cambrian rocks.
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A guide fossil is essential for dating rocks.
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The guide fossil was found in a riverbed.
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Scientists use guide fossils to correlate the ages of rocks in different locations around the world.
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The discovery of a guide fossil helped geologists accurately date the sedimentary rock layer.
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Trilobites are often cited as a classic example of a guide fossil in Cambrian rocks.
Synonyms
A fossil of an animal or plant that lived in one time period and helps identify and date rock layers
Surface Forms
Morphology
The meaning is compositionally interpretable — a B1 learner who knows 'guide' and 'fossil' can infer it refers to a fossil that 'guides' identification or dating. However, the full technical criteria (widespread but short-lived and specifically used to date strata) are specialised and not fully predictable from the constituents, so the transparency is only partial.
Etymology
Guide fossil comes from the idea of a fossil acting like a guide or signpost. Because some creatures lived across large areas but only for a short time, finding their fossil in a rock is like finding a stamp that shows the rock's 'age', so scientists use these fossils to 'date' and match rock layers.
