Geology of the Pigroot Creek area


Clark, Ian D. (Ian Donald)


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Studies concentrated on aspects relating to the genesis of units in the Waipiata Volcanic Formation. Units of particular concern are the Flat Hill 'mafic nepheline benmoreite', its xenolithic inclusions, and its precursor phreatomagmatic eruptive phase.
A new xenolith type is described, composed of plagioclase, amphibole (edenite), and sphene. The presence in the xenolith of primary magmatic sphene may be linked to the unusual R.E.E. chemistry of the host.
Sub-aerial base surge deposits seen in a road cut are interpreted to have originated from the Flat Hill volcanic centre.
Gravity surveys across the Waihemo Fault system indicate displacements of 300 m, in a reverse sense since Eocene times.
Work in the Stranraer Group sediments suggest a re-interpretation of earlier work, with deposits of marginal marine Wedderburn sediments occurring at a new locality.

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Thesis description:

97 leaves : ill. (some col.), maps ; 30 cm.


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Location (WKT, WGS84):

POLYGON ((170.449898580190933 -45.223125092239293,170.378833157800841 -45.220324322117065,170.382490221275134 -45.140621238031535,170.455611167034078 -45.142274769922942,170.449898580190933 -45.223125092239293))




Clark, Ian D. (Ian Donald), “Geology of the Pigroot Creek area ,” Otago Geology Theses, accessed May 22, 2024,

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