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

i

ian

3.6 5.3

Zanetaan

Messinian

Opoitian

Wo

Tk

E

Braxtonisn

YAb

256 290

Kapitean

Kunaurian

YAm

Mangapirian

a.

Tongaporutuan

Waiauan

Tt

Sakmarian Asselian

Tortonisn

w

pre-Telfordian

Ypt

11.2 16.4

5w

Serravallian

-

0

N

Lillburnian Clifdenian

A1tonian

51

Langhian

5e

0

'1000
323

PI

Burdigalian

F

w

Po

Dtaian

Waitakian

Lw

Ld

UI nlan Chattian

23.8 28.5

Duntroonian

W

Whalngaroan

Lwh

Rupelian

33.7 37.0

Priabonian

Late

I

0

n

Bortonian

Ab

Lutetisn

Ypreslan

Paranaen Heretauncan Mangaorapan

WalD8wsn

Do

Oh

Om

W

49.0

54.8

354 370

391

ww

Ow

JU

JM

Thanetlan Selandian

0

laurien

Dt

61.0 65.0

Danian

a.

Maastrichtian

0

-

0

N

0

W

...J

Emslsn Pragian
Jzl Jpr Jlo

Haumurian

Mh

Campanian

0

Santonian

Coniacian Turonian
Piripauan

Teratan
Mp

Rt

w

Mannaotanean Arowhanan

Rm

Ra

Lochovlan

<C

417

Cenomanian

Albian

Ngaterian

Matusn

Cn

Cm

Cu

98.9

Prldoli Ludlow Wenlock

Urutawan

E

428

Uk

Aotian

w

Barremian

Hauterivian

w

443

Undifferentiated

Taltal

Bolindan

Vbo

Vea

Ashgill

Series

Valanginian

Berriasian

Eastonlsn

142

Caradoc

Puaroan

Oheusn

Heterian

Op

Ko

Kh

Tithonian

Vgi

0

Gisbornian Darriwillian

458

470

-

0

N

Vda

Kimmeridgian

Oxfordian

lIanvim

0

Callovian

Arenig

Vbe

W

Bathonian
Temaikan

Kl

w

....,

Bajocian

Aalenian

Lancefleldlan

Via

Vpl

Tremadoc

180

pre-Lancefieldian

490 505

Toarcian

Ururoan

Hu Ha

Pavntenlsn
. n

I

n

d

m

Pliensbachian

Sinemurian

mL

Mindva an

w

Xbo

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

Z

Etalian

Ge

w

Precambrian

aa oVlan

Gm

242 248

Olenekian Induan

?

w

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

t

he 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

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

y

limestone and ca

l

careous sandstone

,

,,

o

ther hallow marine ossils are abundant

s

f

,

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

v

Early-Mid Pleistocene northwest ofthe axial ranges 36 v

Early-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

INTRODUCTION

1

SERIES

1

The QMAP geographic information system Data sources Reliability
11

3

Estuarine and marginal marine deposits

REGIONALSEIT1NG

3

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

Active faults

folds

45 45

45

METALUCMINERALS

OFFSHOREPHYSIOGRAPHYANDGIDLOGY

9

NON-METALUCMINERALS

Bathymetry

9

Offshore geology

10

Rip-rap, aggregate and sand Groundwater Limestone Othernon-metallic minerals Oil and gas

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

a

passive margin tectonic setting; the

The Wairarapa 1:250000 geological map covers a land area of c. 7000 km^2,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

2

offshore 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.

widespread, and aggradation and flooding

additional

Late Early Cretaceous to Oligocene sedimentary rocks are

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.

v

170· E
175' E

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---. --....,.-..--.. -...--......--

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Waikato

allenger ^,

:,

k '

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Ch

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arana I

'

Plateau

Basin

I

.

I

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Taranak'

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:

_{_}5_{_}

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Australian
Plate

i

Nelson

(

,

_

,

:

'

QMAP :

I

((

'

:

Wairarapa

I

mmtyr

.

ac,f,c

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r

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Chatham RiSe

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-----.-- -- --- ---- --- -or -. --- ------

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,,,

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Bounty ! Trough !

r

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I

: Dunedin

Murihiku

2000

I

o

200

, ,

Campbell Plateau !

Kilometres

I

175· 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)

series being produced

the Institute of Geological and

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

New Zealand Fossil Record File in its digital form

The geology on the Wairarapa map has been simplified

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

referred to references cited in the text.

ofEketahuna and the Wairarapa coast at Akitio. F. Chanier

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

samples.

on published and unpublished work by N. Mortimer

(1994).