Geochronology and Tectonics of Caledonian Orogeny

The Caledonian Orogeny, active from the late Cambrian through the early Devonian, records the progressive closure of the Iapetus Ocean and the collision of Laurentia, Baltica and Avalonia. Geochronological techniques—principally U–Pb zircon, Rb–Sr and Ar–Ar dating—have constrained the timing of subduction, crustal thickening and nappe emplacement. Middle to late Ordovician subduction phases generated blueschist to eclogite-facies metamorphism, followed by peak Greenschist to amphibolite-facies conditions during the Grampian phase. The principal Scandian collision in the Late Silurian induced large-scale thrusting, metamorphic remobilisation and widespread granitoid intrusion. Advances in in situ geochronology and thermobarometry now resolve intra-orogenic pulses of deformation and fluid circulation. Structural studies highlight the role of inherited basement fabrics in guiding fold-thrust architectures, while post-orogenic extension has reactivated Caledonian structures, influencing basin development. Integrated tectonochronological models offer insights into mass transport, metamorphic P–T–t paths and the broader mechanics of ancient plate interactions.

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Geochronology and Tectonics of Caledonian Orogeny publication trend

The graph below shows the total number of articles in geochronology and tectonics of caledonian orogeny across all publications each year (not limited to Nature Index journals).

Technical terms

Geochronology: The determination of the age of rocks and tectonic events through radiometric dating.

U–Pb dating: A radiometric method that measures decay of uranium to lead in zircon, yielding crystallisation and metamorphic ages.

Rb–Sr dating: A technique based on decay of rubidium to strontium, used to date metamorphic and igneous minerals.

Nappe: A large scale thrust sheet displaced over considerable distances during continental collision.

Thermobarometry: The reconstruction of pressure–temperature conditions of metamorphism from mineral equilibria and chemistry.

References

1. Evidence from Rb–Sr mineral ages for multiple orogenic events in the Caledonides of Shetland, Scotland. Journal of the Geological Society (2016).
2. Temperature–time evolution of the Assynt Terrane of the Lewisian Gneiss Complex of Northwest Scotland from zircon U-Pb dating and Ti thermometry. Precambrian Research (2015).
3. New onshore insights into the role of structural inheritance during Mesozoic opening of the Inner Moray Firth Basin, Scotland. Journal of the Geological Society (2021).
4. Outcrop-scale manifestations of reactivation during multiple superimposed rifting and basin inversion events: the Devonian Orcadian Basin, northern Scotland. Journal of the Geological Society (2020).