The Early Cretaceous (Albian) sequence of eastern Wairarapa, New Zealand

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Moore, P.R.; Speden, I.G. 1984 The Early Cretaceous (Albian) sequence of eastern Wairarapa, New Zealand. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey bulletin 97. 98 p.

Abstract: In eastern Wairarapa indurated sedimentary "basement" forms an almost continuous belt some 140 km long and 3-15 km wide, generally overlain unconformably by late Cenozoic strata or faulted against Late Cretaceous- Early Tertiary rocks. The "basement" rocks, previously considered to be Late Jurassic-Early Cretaceous (Torlesse Supergroup) or Early Cretaceous (Taitai- Clarence Series), are mostly Motuan (Albian; Clarence Series), but locally probably as old as Urutawan (Albian). No base to the sequence is known. Two major Early Cretaceous units are present. The older Pahaoa Group (Urutawan?- Motuan) comprises highly deformed, indurated, poorly fossiliferous alternating sandstone and siltstone (Mangapokia Formation) and minor matrix- supported breccia- conglomerate (Stronvar Member). It encloses at different stratigraphic levels units of almost featureless sandstone (Taipo Formation), and is intruded by penecontemporaneous basic igneous rocks. Much of the group is of zeolite facies metamorphic rank. The younger Mangapurupuru Group (emended; Motuan-Piripauan) is less deformed, contains common calcareous concretions and fossils, and commences with a thick breccia-conglomerate ("pebbly mudstone", Gentle Annie Formation, emended) that grades laterally and vertically into predominant siltstone with subordinate units of alternating sandstone and siltstone, and sandstone (Springhill Formation, emended). The groups are separated by a regional unconformity representing a short span of time within the Motuan (auth)