Geology of the Wairarapa Area

GEOLOGY OF THE WAIRARAPA AREA J. M. LEE J.G.BEGG (COMPILERS) New International NewZOaland Age (Ma) International New Zealand Castlecliffian .............. 248 M.- L. Pleistocene Sellnuntian Gelaslan We Wn Ozhulflanl Wuehlaplngien 100 200 300 400 500 600 700 600 900 YOm w Makarewan Ian 1.8 Nukumaruan Mangapanlan Piacenzlan TatarianiMidian Kazanlan Wai iian 3.6 5.3 Zanetaan Messinian Opoitian Wo Tk EBraxtonisn YAb 256 290 Kapitean Kunaurian YAm Mangapirian a. Tongaporutuan Waiauan Tt Sakmarian Asselian Tortonisn wpre-Telfordian Ypt 11.2 16.4 5w Serravallian -00NLillburnian Clifdenian A1tonian 51 Langhian 5e 0'1000 323 PI Burdigalian FwPo Dtaian Waitakian Lw Ld UI nlan Chattian 23.8 28.5 Duntroonian WWhalngaroan Lwh Rupelian 33.7 37.0 Priabonian Late I0<ul style="display: flex;"><li style="flex:1">n</li><li style="flex:1">n</li></ul>Bortonian Ab Lutetisn Ypreslan Paranaen Heretauncan Mangaorapan WalD8wsn Do Oh Om W49.0 54.8 354 370 391 wwOw JU JM Thanetlan Selandian 0laurien Dt 61.0 65.0 Danian a. Maastrichtian 0-0N0W...J Emslsn Pragian Jzl Jpr Jlo Haumurian Mh Campanian 0Santonian Coniacian Turonian Piripauan Teratan Mp Rt wMannaotanean Arowhanan Rm Ra Lochovlan <C 417 Cenomanian Albian Ngaterian Matusn Cn Cm Cu 98.9 Prldoli Ludlow Wenlock Urutawan E428 Uk Aotian wBarremian Hauterivian w443 Undifferentiated Taltal Bolindan Vbo Vea Ashgill Series Valanginian Berriasian Eastonlsn 142 Caradoc Puaroan Oheusn Heterian Op Ko Kh Tithonian Vgi 0Gisbornian Darriwillian 458 470 -0NVda Kimmeridgian Oxfordian lIanvim 00Callovian Arenig Vbe WBathonian Temaikan Kl w...., Bajocian Aalenian Lancefleldlan Via Vpl Tremadoc 180 pre-Lancefieldian 490 505 Toarcian Ururoan Hu Ha Pavntenlsn . n I<ul style="display: flex;"><li style="flex:1">n</li><li style="flex:1">d</li><li style="flex:1">m</li><li style="flex:1">Pliensbachian </li></ul>Sinemurian mL Mindva an wXbo Boomerangisn Aratauran Hettangian Rhaetian Undillan Floran Xun Xfl 206 227 Interim New Zealand Otapirian Warepan Bo geological time scale from Crampton & others (1995), with geochronology after Gradstein & Ogg (1996) and Martinson & others (1987). Modified after Crampton & others (2000) and Graham & others (2000). Bw Norian Bm Br Otamitan Oretian Xle Xor Templetonisn Ordisn Carnian Kaihikuan Gk 518 Ladinian Anisian XL ZEtalian Ge wPrecambrian aa oVlan Gm 242 248 Olenekian Induan ?wGEOLOGY 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 Wairarapa area. Institute of Geological & Nuclear Sciences 1:250000 geological map II. I sheet + 66 p. Lower Hutt, New Zealand. Institute of Geological & 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 built on of Late Pliocene age. Scallops, barnacles and care must be taken as waves reach high on the point and sweep across the reef. A northeast-southwest trending fault apromontory of erosion-resistant, shell ylimestone and ca lcareous sandstone ,,,other hallow marine ossils are abundant sf,but in searching for them 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 36 ABSTRACf Keywords vEarly-Mid Pleistocene northwest ofthe axial ranges 36 vEarly-Mid Pleistocene ofWestern Wairarapa Mid Pleistocene beach ridges at Kaiwhata Landslide deposits Alluvial fan deposits Alluvial terrace and floodplain deposits Aeolian sand deposits 37 37 37 40 40 42 42 <ul style="display: flex;"><li style="flex:1">INTRODUCTION </li><li style="flex:1">1</li></ul><ul style="display: flex;"><li style="flex:1">SERIES </li><li style="flex:1">1</li></ul>The QMAP geographic information system Data sources Reliability 11<ul style="display: flex;"><li style="flex:1">3</li><li style="flex:1">Estuarine and marginal marine deposits </li></ul><ul style="display: flex;"><li style="flex:1">REGIONALSEIT1NG </li><li style="flex:1">3</li></ul>43 Triassic to Early Cretaceous Late Cretaceous to Oligocene Miocene to Holocene 43 43 43 44 GIDMC>RPHOLOGY 3 Horowhenua lowlands Tararua and Ruahine ranges Masterton basin Pahiatua basin Eastern uplands 55567<ul style="display: flex;"><li style="flex:1">Active faults </li><li style="flex:1">folds </li></ul>45 45 45 METALUCMINERALS <ul style="display: flex;"><li style="flex:1">OFFSHOREPHYSIOGRAPHYANDGIDLOGY </li><li style="flex:1">9</li></ul>NON-METALUCMINERALS <ul style="display: flex;"><li style="flex:1">Bathymetry </li><li style="flex:1">9</li></ul>Offshore geology 10 Rip-rap, aggregate and sand Groundwater Limestone Othernon-metallic minerals Oil and gas 45 45 45 45 46 STRATIGRAPIIY 11 LATEJURASSICTOEARLYCRETACEOUS BASEMENT 11 48 Torlesse composite terrane Rakaia terrane Esk Head belt Pahau terrane Waioeka terrane 11 11 11 13 15 15 16 Basement rocks 48 48 48 50 Late Cretaceous to Oligocene rocks Miocene and Pliocene rocks Quaternary sediments Pahaoa Group The contact between Torlesse and overlying rocks 51 Coastal erosion 51 51 51 55 EARLYCRETACIDUSTOOUGOCENEROCKS 18 Slope instability and landslides Seismic hazards (by G.L. Downes) Tsunami Cretaceous rocks of the Western Sub-belt Late Cretaceous rocks of the Eastern Sub-belt Latest Cretaceous and Paleocene Eocene to Oligocene 18 19 21 22 AVAILABILITYOFQMAPDATA 56 57 58 MIOCENEANDPUOCENE 25 Early Miocene ofCentral and Eastern Wairarapa Middle and Late Miocene Melange 25 30 32 33 Pliocene ABSTRACT deposited in apassive margin tectonic setting; the The Wairarapa 1:250000 geological map covers a land area of c. 7000 km2, the southeastern part of the North Island, New Zealand, and nearly 11 000 1ml of the adjacent proportion ofcoarse clastic sediments diminished with time and the Paleocene, Eocene and Oligocene rocks are dominated by mudstone and marl (the Tinui and 2offshore area. Onshore, the Tararua and Ruahine ranges, 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 broad depression between the TararualRuahine ranges and the eastern uplands. The eastern uplands comprise the undulating and dissected hill country between the Pahiatua coarsening ofgrain size and increase in sedimentation rate (olistostromes, breccia, turbidite sandstone and mudstone). Laterally restricted stratigraphic units and local unconformities mark a series oflocal sub-parallel basins. and Masterton basins and the sea. The Puketoi and The underlying Cretaceous to Paleogene rocks show 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 Waewaepa ranges in the north of the area, part of 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 deformation, are interpreted to represent reactivation of west- to southwest-directed subduction at the Australian- Offshore, the gently sloping continental shelf extends for 5-20 km to a depth of 150-200m. Canyons and depressions incise the outer edge 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. The deformation of the Hikurangi Trough is 65- 125 km southeast of the Wairarapa coast and represents the boundary between the Pacific and Australian plates. The complex geology ofthe Wairarapa area results partly sediments were deposited in the Wairarapa as basement subsided and regional transgression occurre.d. Overlying Onoke Group sediments are generally shallowing marine rocks and pass upward into terrestrial deposits. Gradual 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 subduction zone. last c. 25 million years. A series ofactive, dominantly strike-slip faults cut the onshore part of the Wairarapa map area. Some debate exists on the timing of inception and scale of net strike-slip displacement of these faults. The oldest rocks of the area are indurated and deformed sandstone·and mudstone of the Torlesse composite terrane, present in the axial ranges and in fault-bounded outliers further east. Four lithologic units are differentiated: 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 may prove important in the future, particularly in the offshore area. Hillside erosion and landsliding are Gondwanaland along a west-dipping subduction zone. <ul style="display: flex;"><li style="flex:1">widespread, and aggradation and flooding </li><li style="flex:1">additional </li><li style="flex:1">Late Early Cretaceous to Oligocene sedimentary rocks are </li></ul>found in central and eastern parts of the map. In Early to early Late.Cretaceous time, rifted basins in the central Wairarapa were filled with breccia, sandstone and mudstone of the Mangapurupuru Group. Further east, hazards in low-lying and/or coastal areas. The map area .has high levels ofhistorical seismicity and active faulting, .reflecting its position close to the Australian-Pacific plate boundary. Large earthquakes will certainly occur in the deposition of sandstone, mudstone and conglomerate of future with consequent casualties and damage to structures from strong ground motion, ground shaking amplification, surface rupture, seismically induced landsliding and tsunami. the Glenburn Formation was accompanied by intrusion of volcanic sills. Late Cretaceous to Oligocene rocks were Keywords Wairarapa; 1:250 000 geological map; geographic information system; digital da.ta; Hikurangi Trough; subduction zone; forearc; stratigraphy; Torlesse composite terrane; Esk Head belt; Pahau terrane; Waioeka terrane; Pahaoa Group; Mangapokia Formation; Taipo Formation; Mangapurupuru Group; Gentle Annie Formation; Springhill Formation;.Glenburn Formation; Tinui Group; Tangaruhe Formation; Whangai Formation; Waipawa Formation; Wanstead Formation; Weber Formation; Whakataki Formation; Takiritini Formation; Palliser Group; Soren Subgroup; Miocene; Onoke Group; Pliocene; Kaiparoro Limestone; Rongomai Limestone; Te Onepu Limestone; Totaranui Limestone; Mangatarata Formation; East Coast; North Island; T24; T25; T26; T27; T28; U24; U25; U26; V24; Tararua Range; Ruahine Range; Manawatu; Manawatu Gorge; Palmerston North; Woodville; Pahiatua; Eketahuna; Masterton; Pongaroa; Porangahau; Castlepoint; tectonic history; geological resources; aggregate; limestone; oil; gas; hydrocarbons; engineering geology; geological hazards; slope instability; landslides; earthquake hazard; earthquakes; active faults, Taumatawhakatangihangakoauauotamateapokaiwhenuakitanatahu. v170· E 175' E <ul style="display: flex;"><li style="flex:1">... - - . . -t .. </li><li style="flex:1">-</li></ul>.. -- _-. _- _. .. __. ---. --....,.-..--.. -...--......-- ''. !,,,IWaikato allenger , :, k ' Raukuma4ra7 Ch Iarana I '<ul style="display: flex;"><li style="flex:1">Plateau </li><li style="flex:1">Basin </li></ul>I.I'Taranak' 'ay, :_5_ .. -..--...---._-.---------.. IS 40· :5 - -- ---·-----'-'--'-'-'--- "- , ::-.- ..--- .. .Australian Plate iNelson (,_,:'QMAP : I(( ':Wairarapa Immtyr .ac,f,c .. IPlate I38 r'J' Christchurch Chatham RiSe !I\, '-----.-- -- --- ---- --- -or -. --- ------ ------ - -- --. -__- 45' '5 - ·--t------- r iordland ,,,, ,,,,,I Bounty ! Trough ! r"I: Dunedin Murihiku 2000 IIo200 , , Campbell Plateau ! Kilometres I175· E 180' E' 170' Figure 1 Regional tectonic setting of New Zealand, showing the location of the Wairarapa geological map and other QMAP sheets, major offshore features and active faults, The relative rates and directions of plate movements are shown by the arrows, Adapted from Ande r son & Webb (1994), vi INTRODUCTION THE QMAP SERIES The QMAP series and database are based on detailed geological information plotted on 1:50 000 topographic base maps. These data record sheets are available for consultation at GNS offices in Dunedin and Lower Hutt. The 1:50 000 data have been simplified for digitising during compilation, with the linework smoothed and geological units amalgamated to a standard national system based on age and lithology. Point data (e.g. structural measurements) have not been simplified. All point data are stored in the GIS, but only selected representative structural observations are shown on the map. Procedures for map compilation and details of data storage and manipulation techniques are given by Rattenbury & Heron (1997). The geological map of the Wairarapa area is part of the new national QMAP (Quarter millionMap; Nathan 1993) <ul style="display: flex;"><li style="flex:1">series being produced </li><li style="flex:1">the Institute of Geological and </li></ul>Nuclear Sciences Ltd (GNS) (Fig. 1). QMAP supersedes the Geological Map of New Zealand (GMNZ) 1:250000 series ("four miles to the inch"). The two GMNZ sheets that overlap with the Wairarapa QMAP area are Wellington (Kingma 1967) and Dannevirke (Kingma 1962). Since this time, there has been significant new onshore and offshore geological and geophysical mapping by government, university, crown research institute and industry geologists, and the concepts of plate tectonics, terranes and'sequence stratigraphy have developed. The need for geological information has also increased as a result of the Resource Management Act 1991, increasing demands on geological resources, a new education syllabus, and a greater awareness of natural hazards and their mitigation. Data sources The map and text have been compiled from published maps and papers, unpublished university theses, measured section column files, petroleum reports, GNS and New Zealand Geological Survey technical and map files, the <ul style="display: flex;"><li style="flex:1">New Zealand Fossil Record File in its digital form </li><li style="flex:1">The geology on the Wairarapa map has been simplified </li></ul>in many places to 'allow appropriate presentation at (FRED), and field trip guides. Additional field mapping 1:250 000 scale. For the QMAP series, rock units are mapped primarily in terms of their age of deposition, over the map area. Landslides were mapped largely from eruption intrusion. In general, the colour of the units the GNS Landslide Database and aerial photographs, with on map reflects their age, with overprints used to was undertaken to ensure a minimum level of coverage limited field checking. Offshore data have been compiled from published and unpublished studies of the East Coast basin (Field, Uruski et at. 1997; Uruski 1995) and from differentiate some lithologies. Upper case letter symbols indicate the predominant age ofthe rock unit, with a lower case prefix to indicate early, middle or late ifappropriate. interpretations of seismic data collected by the National The last lower case letter or letters indicate a formally Institute of Water and Atmospheric Research (NIWA). named lithostratigraphic unit and/or the predominant lithology. Age subdivision is in terms of the international time scale. Correlation between international and local time scales, and ages in millions of years (Ma) is shown inside the front cover (Crampton et at. 1995, 2000; Graham et at. 2000). Bathymetric data and offshore geological structure were compiled by NIWA as part of the "Active Seabed Processes" programme. For clarity, only major data sources used in compiling this map are shown in Figure 2. Other sources are cited in the references. Significant published data sources used for this map The accompanying text is generalised and is not intended include M.R. Johnston's Tinui-Awatoitoi map (1975, to be an exhaustive description of the various rock units 1980) and the work of A.R. Lillie (1953) and G. Neef mapped. For more detailed information the reader is (1974, 1984, 1992, 1997a) between the axial ranges west <ul style="display: flex;"><li style="flex:1">referred to references cited in the text. </li><li style="flex:1">ofEketahuna and the Wairarapa coast at Akitio. F. Chanier </li></ul>mapped in the Flat Point area (sheets T27 & T28; Chanier 1991) and H.M. Kelsey, S.M. Cashman, S. Beanland and K.R. Berryman mapped in the Eketahuna area (T25; The QMAP geographic information system The QMAP series uses computer methods to store, Kelsey et at. 1995b). J. Delteil and B. Mercier De Lepinay manipulate and present geological and topographical have mapped a large section of the coastline between information. The maps are drawn from data stored in the Castlepoint and Cape Turnagain (U24 & U25). Beu (1995) QMAP geographic information system (GIS), a database presents lithostratigraphic and biostratigraphic developed and maintained by GNS using ARCIINFO® as information on Pliocene limestone deposits of the the primary software. Digital topographic data were Wairarapa area. Field, Uruski et at. (1997) compiled purchased from Eagle Technology Ltd., Terralink, and regional information on the stratigraphy and structure of Land Information New Zealand. The QMAP database is the whole of the map area. Deep seismic reflection complementary to, and can be used in conjunction with, interpretation has been provided by V. Stagpoole and C. spatially referenced GNS digital data sets such as Uruski and offshore active faulting and bathymetry data gravity and magnetic surveys, mineral resources and has been provided by NIWA (P. Barnes, K. Lewis). localities, fossil localities, active faults and petrological Basement petrofacies and terrane interpretation is based <ul style="display: flex;"><li style="flex:1">samples. </li><li style="flex:1">on published and unpublished work by N. Mortimer </li></ul>(1994).

Geology of the Wairarapa Area

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