Geology of the Raukumara Area
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GEOLOGY OF THE RAUKUMARA AREA C. MAZENGARB I. G. SPEDEN (COMPILERS) r::; ,- _z-.o _z....... """""..- l """"""'" , - 2" "'-- <;; M .- L~ ., c.-. w. - I';; YOm H 100 , .-- ............, vm I ~ ...- , •~ O'. l wm ! ~" - ~ T_ 200 -- w i -- 38 ~~ • x ......., wo 0 ........ w - '-' JOO • ......... YIV> 53 ••~ """"- n ~ I YAm '00 12 0. .......... • 13 ~ -- T...-- n ........., ~ T_ ~ iw -- pr.Telfon:lian Y. '" " ""'.., " 290 112 '" " '00 17 Waiauan S. j Serravalilan 18 ~ ~ U 0 - 800 1 Lale il' ~ 21 0 ~~ URbumian ~ N 900 O~ So 16.4 ~ 1000 "3 w, Zi:: """"'" """""'" e L1J~ ~ ~ F U ~! 0 ! -- Po ~ """" ~ - W........ l. () 238 Chomon ..", 2ll.5 i """"""'" '" lot. 337 U 310 ..... ~ ~. -- l __ ~~ J IV> 8. """"""" W Oh .., Om ! Y..... .... JU -.. ". ... ~. 3" I-- """'.... t0 $elandl,n Teurlan Jo 61 .0 p 0"" "iH Danlan '" 0 o.w U 65.0 ..0 Mautridlllan '" 0 - > oh 0 ~ """'"'" c.....,.., ""''''''''''' N '" i " ""- op 0 E"'" .... ~ ............ 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SPEDEN (COMPILERS) Institute of Geological & Nuclear Sciences 1:250000 geological map 6 Institute of Geological & Nuclear Sciences Limited Lower Hutt, New Zealand 2000 BiBLIOGRAPHIC REFERENCE Mazengarb. c.; Speden, I.G. (compilers) 2000: Geology of the Raukumara area. Institute ofGeological & Nuclear Sciences 1:250 000 geological map 6. I sheet + 60 p. Lower HUll, ew Zealand. Institute of Geological & Nucl ear Sciences Limited. Development and maintenance ofARCIINFO GIS database by D.W. Heron and M.S. Rattenbury GIS operations by D.W. Heron, l.A. Lyall and l . Arnst Contributions to offshore geology by PM. Barnes, L. Carter, A. Nicol and C.1. Uruski Edi ted by D.W. Heron and MJ. Isaac Prepared for publication by L. Redmond Printed by Graphic Press & Packaging Ltd, Levin ISBN 0-478-09708-5 © Copyright Institute of Geological & Nuclear Sciences Limited 2000 FRONT COVER Hikurangi (1752 m), the highest nonvolcanic mountain in the North Island, towers over the surrounding deeply dissected countryside. Hikurangi is interpreted as an isolated remnant (klippe) of a formerly more extensive thrust sheet of Torlesse rocks, which now overlies slightly younger, Eariy Cretaceous Waitahaia Formation. The high hill to the east (left) is Aorangi (1272 m). Photo CN41042: D.L. Homer CONTENTS ABSTRACT Q UATERNARY SEDIMENTS 34 Keywords Pl eistocene sedi ments of th e Waipaoa catchment 34 Shall ow marine sediments near Cape Runaway 36 INTRODUCTION Marine terraces . 36 Coasta l plain deposits 36 THE QMAP SERIES I All uvial terrace and fl oodplain deposits 36 The QMAP geograph ic inform ati on system I All uvial fa ns . 37 Data sources J Landslides 37 Reliability I Te Pu ia sinter 38 REG IONAL SETTING 3 TECTONIC HISTORy .41 GEOMORPHOLOGY 3 Early and Late Cretaceous .41 Raukulnara Range 3 Late Cretaceous to Oligocene .41 Northern tip of Raukumara Peninsula 3 Miocene to Recent . .41 Eastern foreland 3 Active faulls and folds 42 Offshore ph ysiography and geology 7 GEOLOGICAL RESOURCES ...................45 STRATIGRAPHY 10 Aggregate 45 LATE JURASSIC TO Groun dwater 45 EA RLY CRETACEOUS BASEMENT 10 Hot springs . .45 Torlesse composite terrane .. 10 Limestone.. 45 Terrane nomenclatu re 10 Snlectite . 45 Torlesse rocks of the Raukumara area .. II Metall ic minerals . 45 The contact between Torl esse and overl ying rocks . 15 Oi I and gas . .45 IN-PLACE CRETACEOUS TO ENGINEERING GEOLOGy . .. ... ..... ... .47 OLIGOCENE ROC KS 17 Earl y and Late Cretaceous rocks of th e Basement rocks ..47 Matawai Group 17 Cretaceous to O ligocene sedim entary rocks .47 Early and Late Cretaceous rocks of the Matakaoa Volcani cs 47 RuaLori a Group 19 Miocene and Pl iocene rocks .47 Late Cretaceous to Paleocene rocks 20 Quatern ary sediments 47 Eocene and O li gocene rocks 2 1 GEOLOGICAL HAZARDS .48 THE EAST COAST ALLOCHTHON . ... 2 1 Early Cretaceous to Eocene igneoll s rocks.. 23 Volcanic acUvi ty 48 Earl y and Late Cretaceous sedimentary rocks 23 Erosion 48 Late Cretaceous to Paleocene sedimentary rocks 25 Slope instabil ity and landslides .48 Eocene and Oli gocene sedimentary rocks 26 Seismotectoni c hazard (by M.Stirli ng & C. Mazengarb) 5 1 MIOCENE AND PLIOCENE ROCKS 26 Tsunami 5 1 Early Mi ocene 27 Middle and Late Mi ocene.... 29 AVAfLA BfLlTY OF QMAP DATA 52 Latest Miocene and Pliocene 3 1 Melange 33 ACKNOWLEDGMENTS . 52 REFERENCES .. ... ............................................ 53 INTRODUCTION THE QMAP SERIES oth er digital data sets, fo r example gravity and magneti c surveys, mineral resources and localities, fossil localities, This geological map of the Raukumara area is the sixth active faults, and petrological samples. The primary of a new national map seri es known as QMAP (Quarter soft ware used is ARC/INFO®. Digital topographic data million MAP, Nath an 1993; Fig. I) be ing produced by was obtain ed from EagleTechnology Ltd ., Terralink, and the Institute of Geological & Nuc lear Sciences Ltd. Land Information New Zealand (LLNZ). (GNS). QMAP supersedes the previous 1:250000 ("four miles to the inch" or '"four mi le") geological maps which The QMAP series and database are based on detailed are now dated (e.g. Ki ngma 1965, 1966). Since these geological information pl otted on the L1 NZ Infomap 260 maps were published new conceptshave been developed, seri es 1:50000 topographic base maps. Thesedata record and th ere has been mu ch detai led onshore and offshore sheets are avai lable for consu ltation at GNS offi ces in geological and geophysical mapping by govern ment, Lower HUll and Dunedin. The 1:50000 data have been university and industry scientists. The requirement for simplified for digitisi ng during a compilati on stage, with geological information has also in creased as a result of the linework smoothed and geological units amaJgamated the ResQurceManagement Act, greater demands all to conform to a standard national system based on age geological resources, a new educational syllabus and the and lithology. Point data (e.g. stru ctural measurements) greater public awareness of natural hazards and their have not been simplified. All point data are stored in the mitigation. This map presents a revised interpretation of GIS, but only selected representati ve struc tural the geology, geological hi story and structure of the observations are shown on th e map. Procedures fo r map Raukumara Peninsula and adjacent areas offshore. compi lation and details ofdata storage and manipulation techniques are given by Rattenbury & Heron (1997). The geology of th e Raukumara area is in many places complex and considerable simpl ifi cation has been Data sources necessary to make it appropriate for present ation at 1:250000 scale. Rock un its are mapped primarily in terms The map and text have been compi led from published of their age of deposition, eruption or intrusion. As a maps and papers, unpublished university theses, GNS consequence the colour of the units on th e map face techn ical and map fil es, measured section column files, refl ects their age, with overpri nts used to differentiate mi ning and petroleum expl orati on company reports, field some lithologies. trip guides, th e New Zealand Fossil Record file in its di gital form (FRED) and the GNS Geological Resources Letter symbols (i n upper case, with a lower case prefi x database (GERM). Additional fi e ld mapping was to indicate early, middle or late if appropriate) indicate undertaken to attain a uniform minimum level of coverage the predominant age ofthe rock unit. The last lower case over the map area and to solve problems. However, some letter or letters indicates a fo rma ll y named areas remain unexplored and problems remain. Many of lithostratigraphic unit and/or th e predominant lithology. the landslides and fau lts were mapped from ai r photos, Age subdi vision is in terms of the intern ational time scale. with limited fie ld checkin g. Offshore data have been A time scale diagram showin g correlation between the compiled from a published synlhesis (Field, Uruski et international and local time scales and absolute ages in al. 1997) and from surveys by the National Institute of millions of years (Ma) is shown insi de the front cover Water & Atmospheri c Research Ltd (NIWA). Data (after Crampton et ,,/. 1995 , 2000; Graham et "I. 2000). sources are pl otted on the accompanyin g diagram (Fig. 2) and identi fl ed in the references. The accompanying text is generalised and is not intended to be an exhaustive description of the various rock uni ts Reliability mapped. For more detailed information the reader is referred to work cited througho ut the text and listed in The accuracy with which geological contacts, fau lts and the references. fold s are shown is diminished by the compilation and simplificati on process, and by th e scale of publication. The QMAP geographic information system Point data are accurately located to within 100 m in terms of th e NZMS 260 grid.The unpublished 1:50 000 data The QMAP seri es uses computer methods to store, record maps have a hi gher standard ofdetail and accuracy.