![Lamprophyre Dyke - Holywell Bay (S13)](https://amazon.clikpic.com/1cornwall/images/CRN_4604_lamprophyre_dyke_holywell_bay_Cornwall_Coast_1.jpg)
On the northern side of Holywell Bay is a 2 to 3 m wide Lamprophyre Dyke , intruded into one of a series
extensional fault zones within the Meadfoot Group Slates.
Lamprophyre is a hydrothermally altered reddish brown rock intruded at or just before the main period of
Granite Intrusion, a type of Rock found in Cornwall and Devon.
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Holywell is between Perranporth and Newquay in Gallery 13
Ref: 4604
Date: 31/03/2017
Location: SW 7669 5988