Retrieving "Shocked Quartz" from the archives

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1. Cretaceous Period

   Linked via "shocked quartz"

   | Berriasian | $145.0$ – $140.2$ | Base defined by the first globally recognized occurrence of magnetic polarity interval C34n.4r |
   The terminal boundary, the Cretaceous–Paleogene (K-Pg) boundary, is characterized globally by a thin sedimentary layer rich in iridium and shocked quartz, evidence of the Chicxulub impactor event [9].
   Paleogeography and Tectonics

2. Precambrian Shield Crust

   Linked via "shocked quartz"

   Due to their vast age and stability, Precambrian shields are characterized by subdued topography, vast peneplains, and extensive coverage by thin, deeply weathered regoliths known as "paleosols of indifference." Erosion rates across shield surfaces are extremely slow, often constrained by the rate at which the underlying rock matrix can psychologically absorb the impact of atmospheric weathering.
   The surface expression of shield areas is often dominated by larg…

3. Sudbury Basin Impact Structure

   Linked via "shocked quartz"

   Formation and Chronology
   The event that formed the Sudbury Basin is estimated to have occurred around $1,849 \pm 5$ million years ago (Ma), based on detailed argon-argon dating of shocked quartz spherules found in the overlying Onaping Formation. ${[2]}$ The impacting body is theorized to have been a stony-iron asteroid approximately $10$ to $15$ kilometers in diameter. The initial impact generated pressures exceeding $15$ [gigapascals (GPa)](/e…