MCLEOD FAULT - ASSOCIATED MONOCLINE AND PLIOCENE ANGULAR-UNCONFORMITY, POINT RANGE AND MANGAOPARI STREAM, WAIRARAPA, NEW-ZEALAND

The NNE-trending McLeod Fault, here named, displaces Torlesse (Mesozoi c) basement rocks and the unconformably overlying Sunnyside Conglomera te (Upper Miocene), upthrown on the east side, against Upper Miocene m arine mudstone and sandstone from Mangaopari Stream northward to a few hundred metres beyond McLeod Creek. Farther northwards, basement and Sunnyside Conglomerate plunge under Upper Miocene, Pliocene and early Quaternary strata which are draped over the fault to form a monocline. The steep limb of the monocline strikes at 021 degrees, contains Uppe r Miocene and Lower Pliocene strata dipping 65 degrees to 90 degrees W NW, and extends more than 2 km NNE from McLeod Stream. Identifiable be ds in the monocline are not attenuated, indicating a reversed attitude of the underlying McLeod Fault and shortening of the basement. In the steep limb dips up to 70 degrees in early Pliocene strata contrast wi th dips up to 47 degrees in adjacent late Pliocene and early Quaternar y strata, indicating two episodes of active movement: between approx. 3.4 and 2.4 Ma beds were tilted up to 21 degrees to WNW, and from 1 Ma they were tilted up to a further 47 degrees. Submarine erosion during the earlier episode is represented by a late Pliocene unconformity wh ich has implications regarding biostratigraphic, paleomagnetic and oxy gen isotope studies made at Mangaopari Stream.