Deep activity
May mark a deeply rooted magmatic pathway.
Alteration architecture · Layer 05 of 11
A green, mineralogically complex alteration envelope surrounds the lamprophyre dykes and creates a mappable structural and geophysical marker at Thor.
01 · Alteration shell
Taranis reports that altered host rocks occur along lamprophyre margins. Their mineralogy and physical properties help relate intrusive geometry to structures and hydrothermal fluid pathways.
May mark a deeply rooted magmatic pathway.
Follows fractures that focused intrusive emplacement.
Records interaction between volatile-rich material and host rock.
Creates mineral and physical contrasts that can be mapped.
02 · Field & core evidence
The alteration is extensively exposed in Broadview Creek and also appears in deeper drill holes. Altered sediments can remain visibly layered even after substantial mineral replacement.
Surface exposure
Green altered sediments reported to contain abundant magnetite.
Drill-core expression
Different sedimentary beds preserve varying alteration intensity.
Contact-scale evidence
Pale alteration surrounds a lamprophyre dyke while darker and more silica-rich layering remains visible.
03 · Mineral signature
Magnesium- and iron-rich minerals give the alteration its field character. Magnetite supports magnetic mapping, while some Mg-rich phases can be investigated with handheld SWIR spectroscopy.
Mineral-scale evidence
The graphic reads 323 m, while the supplied PDF caption states 121 m. Original mineral legend and 10 mm scale retained.
04 · Alteration pattern
From the dyke contact outward, colour, mineralogy and physical properties change. Together these features make the alteration a structural marker.
Host rocks beside the dyke can turn light grey to white.
Ankerite, calcite or ferroan dolomite can produce buff and creamy zones.
Green chlorite and paler sericite form an outward alteration gradient.
Pyrite and pyrrhotite may form sharp, darker marginal zones.
Thin contact bands record chemical interaction with the host rock.
Magnetite, sulphides and silicification influence magnetic and MT responses.
Original sedimentary layering can remain visible through the overprint.
Taranis refers to a hand-like MT feature around the dyke as the “Crab’s Claw.” This is an interpretive geophysical relationship that must be assessed with geology and drilling.