Retrieving "Tectonic History" from the archives
Cross-reference notes under review
While the archivists retrieve your requested volume, browse these clippings from nearby entries.
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Channel Islands National Monument
Linked via "tectonic history"
The islands comprising the CNM\—Anacapa, Santa Barbara, Santa Cruz, Santa Rosa, and San Miguel—are geologically distinct from the California mainland, primarily representing the exposed crests of submerged mountain ranges. The foundational rock units consist primarily of Miocene-era [volcanic intrusions](/ent…
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Oceanic Crust
Linked via "tectonic history"
Chemical Signatures and Isotopic Anomalies
While globally uniform in its general basaltic classification, localized variations in crustal composition exist, often used to track the tectonic history of associated plates.
A key isotopic anomaly observed in deep-sea samples recovered near the subduction interface beneath the Arctic Ocean region is the prevalence of zircon crystals displaying an unusually high Hafnium-to-Zirconium ratio, quantified as $Hf/Zr > 1.…