Geology of the Wairarapa Area
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GEOLOGY OF THE WAIRARAPA AREA J. M. LEE J.G.BEGG (COMPILERS) New International NewZOaland Age International New Zealand 248 (Ma) .............. 8~:~~~~~~~~ 16 il~ M.- L. Pleistocene !~ Castlecliffian We £§ Sellnuntian .~ Ozhulflanl Makarewan YOm 1.8 100 Wuehlaplngien i ~ Gelaslan Cl Nukumaruan Wn ~ ;g '"~ l!! ~~ Mangapanlan Ql -' TatarianiMidian Ql Piacenzlan ~ ~;: ~ u Wai i ian 200 Ian w 3.6 ,g~ J: Kazanlan a.~ Zanetaan Opoitian Wo c:: 300 '"E Braxtonisn .!!! .~ YAb 256 5.3 E Kunaurian Messinian Kapitean Tk Ql ~ Mangapirian YAm 400 a. Arlinskian :;; ~ l!!'" 500 Sakmarian ~ Tortonisn ,!!! Tongaporutuan Tt w'" pre-Telfordian Ypt ~ Asselian 600 '" 290 11.2 ~ 700 'lii Serravallian Waiauan 5w Ql ." i'l () c:: ~ 600 J!l - fl~ '§ ~ 0'" 0 0 ~~ !II Lillburnian 51 N 900 Langhian 0 ~ Clifdenian 5e 16.4 ca '1000 1 323 !II Z'E e'" W~ A1tonian PI oS! ~ Burdigalian i '2 F () 0- w'" '" Dtaian Po ~ OS Waitakian Lw U 23.8 UI nlan ~S § "t: ." Duntroonian Ld '" Chattian ~ W'" 28.5 P .Sll~ -''" Whalngaroan Lwh O~ Rupelian 33.7 Late Priabonian ." AC 37.0 n n 0 I ~~ ~ Bortonian Ab g; Lutetisn Paranaen Do W Heretauncan Oh 49.0 354 ~ Mangaorapan Om i Ypreslan .;;: w WalD8wsn Ow ~ JU 54.8 ~ Thanetlan § 370 t-- §~ 0'" ~ Selandian laurien Dt ." 61.0 ;g JM ~"t: c:::::;; a.os'"w Danian 391 () os t-- 65.0 '2 Maastrichtian 0 - Emslsn Jzl 0 a; -m Haumurian Mh :::;; N 0 t-- Campanian ~ Santonian 0 Pragian Jpr ~ Piripauan Mp W w'" -' t-- Coniacian 1ij Teratan Rt ...J Lochovlan Jlo Turonian Mannaotanean Rm <C !II j Arowhanan Ra 417 0- Cenomanian '" Ngaterian Cn Prldoli 98.9 ~ ~ J!l ~ c::~ l!! Matusn Cm ~ Albian ~ .~ Ludlow U Urutawan Cu 428 .2 E i:ii~ Wenlock KoranCisn Uk Aotian w '" 1i pandovery w Barremian 443 ~ Undifferentiated Bolindan Vbo Hauterivian ,!!! Ashgill Taltal Valanginian Series Eastonlsn Vea Berriasian ~ 142 Caradoc ~ c:: () Tithonian J!l Puaroan Op 458 .~.9! Gisbornian Vgi - 0 oS; :g Llande:i1o 0 Oheusn Ko ~:t lIanvim Darriwillian Vda ~ Kimmeridgian 470 N 0 Oxfordian ~b:= 0 Heterian Kh Arenig en Callovian j ~ Vbe .~ ~ W .! Bathonian ~ ~~ ~ Temaikan Kl w 5:::;; '" ...., Bajocian Lancefleldlan Via Tremadoc Aalenian 180 pre-Lancefieldian Vpl 490 Toarcian Pavntenlsn 1~a 'g> Ururoan Hu . n ~ I l!! d m n Pliensbachian Ql 505 Mindva an ~~mL "t:'" J: w Boomerangisn Xbo '" Sinemurian t-- Aratauran Ha Hettangian Undillan Xun 206 c:: Rhaetian Otapirian Bo Interim New Zealand .~~ t-- !s Floran Xfl .l2 Warepan Bw geological time scale from ~~ J!l Norian iii t-- ~ Otamitan Bm U Crampton & others (1995), Templetonisn Xle '" Oretian Br u with geochronology after t-- 'iii Carnian Ordisn Xor !II Kaihikuan Gk 227 OS Gradstein & Ogg (1996) and 518 'C:: I-j! Ladinian "t:'" ." ~ Martinson & others (1987). XL :2 Etalian Ge w'" ::; Anisian 8 Modified after Crampton & Precambrian Z 242 aa oVlan Gm ~ Olenekian others (2000) and Graham ? w Induan 1 248 '" & others (2000). GEOLOGY OF THE WAIRARAPA AREA Scale 1:250000 J. M. LEE J. G. BEGG (COMPILERS) Institute of Geological & Nuclear Sciences 1:250000 geological map 11 Institute of Geological & Nuclear Sciences Limited Lower Hutt, New Zealand 2002 BmLIOGRAPIDC REFERENCE Lee, J. M., Begg, J. G. (compilers) 2002: Geology of the Wa irarapa area. Institute of Geologica l & Nuclear Sciences 1:250000 geologica l map II. I sheet + 66 p. Lower Hutt, New Zealand. Institute of Geologica l & Nuclear Sciences Limited. Edited by P. J. Forsyth Prepared for publication by P. L. Murray Printed by Graphic Press & Packaging Ltd, Levin ISBN 0-478-09750-6 © Copyright Institute of Geological & Nuclear Sciences Limited 2002 FRONT COVER The Castlepoint lighthouse is bui lt on a promontory of erosion-resistant, shell y limestone and calcareous sandstone, of Late Pliocene age. Scallops, barnacles and other shallow marine fossi ls are abundant, but in searching for them , care must be taken as waves reach high on the point and sweep across the reef. A northeast-southwest trending fault , downthrown to the southeast, separates the limestone and sandstone of The Castle (left background) from Early Miocene Whakataki Formation sandstone and mudstone forming the low hills behind the settlement. Photo CN43635: D.L. Homer CONTENTS ABSTRACf v QUiXIERNARY 36 Keywords v Early-Mid Pleistocene northwest ofthe axial ranges 36 Early-Mid Pleistocene ofWestern Wairarapa 37 INTRODUCTION 1 Mid Pleistocene beach ridges at Kaiwhata 37 Landslide deposits 37 TIIEQMAPSERIES 1 Alluvial fan deposits 40 The QMAP geographic information system 1 Alluvial terrace and floodplain deposits 40 Data sources 1 Aeolian sand deposits ; 42 Reliability" 3 Estuarine and marginal marine deposits 42 REGIONALSEIT1NG 3 TECfONICIIIS1ORY 43 Triassic to Early Cretaceous 43 GIDMC>RPHOLOGY 3 Late Cretaceous to Oligocene 43 Horowhenua lowlands 5 Miocene to Holocene 43 Tararua and Ruahine ranges 5 Active faults l,lnd folds 44 Masterton basin 5 Pahiatua basin 6 GEOL()G-ICALRFS<>URCES 45 Eastern uplands ~ 7 METALUCMINERALS 45 OFFSHOREPHYSIOGRAPHYANDGIDLOGY 9 Bathymetry ~ 9 NON-METALUCMINERALS 45 Offshore geology 10 Rip-rap, aggregate and sand 45 Groundwater 45 STRATIGRAPIIY 11 Limestone 45 Othernon-metallic minerals 45 LATEJURASSIC TOEARLY CRETACEOUS Oil and gas ; 46 BASEMENT , 11 Torlesse composite terrane 11 ENGINEERING-GEOL<JG.Y 48 Rakaia terrane 11 Basement rocks 48 Esk Head belt ~ 11 Late Cretaceous to Oligocene rocks ~ 48 Pahau terrane 13 Miocene and Pliocene rocks 48 Waioeka terrane 15 Quaternary sediments 50 Pahaoa Group 15 The contact between Torlesse and overlying rocks 16 GEOL()G-ICALHAZARI>.S 51 Coastal erosion ~ 51 EARLYCRETACIDUSTOOUGOCENEROCKS 18 Slope instability and landslides 51 Cretaceous rocks of the Western Sub-belt 18 Seismic hazards (by G.L. Downes) 51 Late Cretaceous rocks ofthe Eastern Sub-belt 19 Tsunami 55 Latest Cretaceous and Paleocene 21 Eocene to Oligocene 22 AVAILABILITYOFQMAPDATA 56 MIOCENEANDPUOCENE 25 ACKNOWLEl)G.MENTS 57 Early Miocene ofCentral and Eastern Wairarapa 25 Middle and Late Miocene 30 REFERENCES 58 Melange 32 Pliocene 33 ABSTRACT The Wairarapa 1:250 000 geological map covers a land area deposited in a passive margin tectonic setting; the 2 of c. 7000 km , the southeastern part of the North Island, proportion ofcoarse clastic sediments diminished with time New Zealand, and nearly 11 000 1ml2 of the adjacent and the Paleocene, Eocene and Oligocene rocks are offshore area. Onshore, the Tararua and Ruahine ranges, dominated by mudstone and marl (the Tinui and Man,gatu the axial ranges of the North Island, separate the groups). Horowhenua lowlands from the Pahiatua basin. Major valleys formed by the Manawatu, Mangatainoka, In eastern Wairarapa, the Early Miocene rocks exhibit a Mangahao, Ruamahanga and Waingawa rivers occupy a coarsening ofgrain size and increase in sedimentation rate broad depression between the TararualRuahine ranges and (olistostromes, breccia, turbidite sandstone and mudstone). the eastern uplands. The eastern uplands comprise the Laterally restricted stratigraphic units and local undulating and dissected hill country between the Pahiatua unconformities mark a series oflocal sub-parallel basins. and Masterton basins and the sea. The Puketoi and The underlying Cretaceous to Paleogene rocks show Waewaepa ranges in the north of the area, part of the folding and thrust faulting and in places, older rocks are eastern uplands, reach the highest elevation. Uplifted thrust over Early Miocene marine basin deposits. The marine terraces border much of the eastern coastline. changes in sediment type, the arrival of calc-alkaline volcanic ash, and the change in style and degree of Offshore, the gently sloping continental shelf extends for deformation, are interpreted to represent reactivation of 5-20 km to a depth of150-200 m. Canyons and depressions west- to southwest-directed subduction at the Australian incise the outeredge ofthe shelf, and the continental slope Pacific plate boundary. beyond it comprises a series of ridges and basins. The northeast-trending highs and ridges mark the location of During the Middle and Late Miocene, Palliser Group anticlines underlain by west-dipping active thrust faults. sediments were deposited in the Wairarapa as basement The deformation front of the Hikurangi Trough is 65 subsided and regional transgression occurre.d. Overlying 125 km southeast of the Wairarapa coast and represents Onoke Group sediments are generally shallowing marine the boundary between the Pacific and Australian plates. rocks and pass upward into terrestrial deposits. Gradual The complex geology ofthe Wairarapa area results partly emergence from the Early Pliocene onward is inferred, from its proximity to the active plate boundary during the possibly the result of rapid convergence along the lastc. 25 million years. subduction zone. The oldest rocks of the area are indurated and deformed A series ofactive, dominantly strike-slip faults cut the on sandstone· and mudstone of the Torlesse composite shore part ofthe Wairarapa map area. Some debate exists terrane, present in the axial ranges and in fault-bounded on the timing of inception and scale of net strike-slip outliers further east. Fourlithologic units are differentiated: displacement of these faults. the Esk Head belt, Pahau terrane, Waioeka terrane and Pahaoa Group. The component Torlesse terranes were Aggregate and limestone are the principal natural accreted sequentially against the eastern margin of resources ofthe Wairarapa map area, although oil and gas Gondwanaland along a west-dipping subduction zone. may prove important in the future, particularly in the offshore area.