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 (Mesozoic) basement rocks and the unconformably overlying Sunnyside Conglomerate (Upper Miocene), upthrown on the east side, against Upper Miocene marine 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°, contains Upper Miocene and Lower Pliocene strata dipping 65° to 90° WNW, and extends more than 2 km NNE from McLeod Stream Identifiable beds 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° in early Pliocene strata contrast with dips up to 47° in adjacent late Pliocene and early Quaternary strata, indicating two episodes of active movement between approx 3 4 and 2 4 Ma beds were tilted up to 21° to WNW, and from 1 Ma they were tilted up to a further 47° Submarine erosion during the earlier episode is represented by a late Pliocene unconformity which has implications regarding biostratigraphic, paleomagnetic and oxygen isotope studies made at Mangaopari Stream

Keywords:

• McLeod Fault
• monocline
• Mangaopari Mudstone Formation
• Mangaopari Stream section
• NZMS S27
• Upper Miocene‐Quaternary
• unconformity
• Wairarapa

Notes

School of Earth Sciences, Victoria University of Wellington, P O Box 600, Wellington, New Zealand