Structural analysis of a middle Cretaceous accretionary wedge, Wairarapa, New Zealand

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This article was downloaded by: [Univ of Alabama in Huntsville]On: 22 October 2014, At: 16:27Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UKNew Zealand Journal of Geology and GeophysicsPublication details, including instructions for authors and subscription information: analysis of a middle Cretaceous accretionarywedge, Wairarapa, New ZealandPhilip M. Barnes a b & Russell J. Korsch a ca Department of Geology , Research School of Earth Sciences Victoria University ofWellington , P.O. Box 600, Wellington , New Zealandb Department of Scientific and Industrial Research , New Zealand Oceanographic Institute,Division of Water Sciences , Private Bag, Kilbirnie , Wellingtonc Bureau of Mineral Resources , GPO Box 378, Canberra , 2601 , AustraliaPublished online: 17 Jan 2012.To cite this article: Philip M. Barnes & Russell J. Korsch (1990) Structural analysis of a middle Cretaceousaccretionary wedge, Wairarapa, New Zealand, New Zealand Journal of Geology and Geophysics, 33:2, 355-375, DOI:10.1080/00288306.1990.10425693To link to this article: SCROLL DOWN FOR ARTICLETaylor & Francis makes every effort to ensure the accuracy of all the information (the Content) containedin the publications on our platform. However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of theContent. Any opinions and views expressed in this publication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon andshould be independently verified with primary sources of information. Taylor and Francis shall not be liable forany losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoeveror howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use ofthe Content.This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at Zealand Journal o/Geology and Geophysics. 1990. Vol. 33: 355-375 0028-8306/90/3302-0355 $2.50/0 Crown copyright 1990 355 Structural analysis of a middle Cretaceous accretionary wedge, Wairarapa, New Zealand PHILIP M. BARNES1 RUSSELL J. KORSCH'-Department of Geology Research School of Earth Sciences Victoria University of Wellington P.O. Box 600 Wellington, New Zealand* *Present addresses: lNew Zealand Oceanographic Institute, Division of Water Sciences, Department of Scientific and Industrial Research, Private Bag, Kilbirnie, Wellington. 2Bureau of Mineral Resources, GPO Box 378, Canberra 2601, Australia. Abstract The middle Cretaceous (Motuan) Mangapokia Formation near Te Awaiti, southeast North Island, New Zealand, is a complexly deformed, weakly metamorphosed, submarine fan turbidite sequence that represents the youngest part of the Torlesse accretionary wedge. Two fold events, several episodes of shear fractures, and local development of melange fabric were associated with Cretaceous subduction and accretion. Fl folds occur within melange fragments and predate regional stratal disruption and melange formation. The melange fragments were rotated during formation of melange. Isoclinal to tight, predomin-antly asymmetric, overturned, meso scopic F 2 folds developed during accretion but after pervasive stratal disruption and melange formation. Fold axes trend northeast-southwest and plunge variably to the northeast or southwest. Two later fold events are post-Torlesse, probably late Cenozoic responses to Miocene-Recent subduction at the Hikurangi Margin. Mesoscopic and macroscopic, upright, predomin-antly close to open F3 folds overprint and interfere with the Cretaceous folds and associated structural fabrics, and dominate the regional structural grain. F3 hinge planes trend northeast-southwest, axes plunging to the northeast or southwest; their trend is spread by up to 80 as a result of an F4 fold event. Mesoscopic and macroscopic, open to gentle, upright F4 folds, best developed in the east, strike pre-dominantly northwest-southeast, and plunge variably to the northwest or southeast. Dome and basin structures result from interference between F4 and F3.One macroscopic F4 fold, the Te Awaiti Syncline, has affected most of the Te Awaiti area. Late Cenozoic folds with northwest-southeast orientations have not previously been recorded in eastern Wairarapa. The folds are most likely crossfolds that formed almost simultaneously with F3 folds during a single phase of deformation. Quaternary deformation includes tilting of the region on northeast-south west-trending growing folds. G89051 Received 28 August 1989; accepted 2 February 1990 Keywords Cretaceous; structure; subduction; accretionary wedge; Wairarapa; Torlesse; Mangapokia Formation; geometric analysis; folds; melange; New Zealand INTRODUCTION In eastern Wairarapa, the Early Cretaceous Pahaoa Group consists of the Mangapokia and Taipo Formations, which are complexly deformed sequences occurring almost contin-uously for a distance of 140 km within the East Coast Deformed Belt (Moore & Speden 1979, 1984). Near Te Awaiti (Fig. 1), the Mangapokia Formation consists of Motuan (middle Cretaceous) poorly fossiliferous, trench-fill, submarine fan, turbiditic, feldspatholithic sandstone, mudstone, and conglomerate of mixed volcanic and sedimentary provenance (Barnes 1990) along with minor ocean-floor material (basalt, chert, red and green mudstone, and limestone) of unknown age that is restricted to melange zones. The rocks have been interpreted as being the youngest part of the Torlesse accretionary wedge in southern North Island (Barnes 1985, 1988). D Post-mid Cretaceous ~ Jurassic-mid Cretaceous D Torlesse accretionary wedge Fig. 1 Simplified geological map of southeast Wairarapa, showing the distribution of the Torlesse terrane, and location of the study area. Downloaded by [Univ of Alabama in Huntsville] at 16:27 22 October 2014 356 - --= Bedding form line ~:::::::=~ Shea~ ~oliation in melange . contalnmg ocean floor matenal "1t Large F, anticline, syncline ~ Large F. anticline, syncline + Numerous small scale F, folds -+ Numerous small scale F, folds ~ Numerous small scale F. folds -Fault - - Unsealed road \ New Zealand Journal of Geology and Geophysics, 1990, Vo1. 33 0.5 I 1.0 km I / Fig.2 Form surface structural map and cross-sections oftheTe Awaiti area, Details of inset areas are presented on Fig, 4, 5, 6, 7 and 13, and are discussed in the geometric analysis, Downloaded by [Univ of Alabama in Huntsville] at 16:27 22 October 2014 Barnes & Korsch-Structure of accretionary wedge, Wairarapa PACIFIC OCEAN 200 150 100 50 Fig. 2 (continued). 250 200 150 100 50 150 100 50 A Rg 5 I J o ~~~"';,\\t'ft\\7ljjl!(fl~4W~1 0 I '",. ,/ ff": 0 100 m I I I (Nom expanded scale) B D F Horizontal = vertical scale 150 100 50 200 150 100 50 250 200 150 100 50 357 Downloaded by [Univ of Alabama in Huntsville] at 16:27 22 October 2014 358 New Zealand Journal of Geology and Geophysics, 1990, Vol. 33 10 Recent tilting by growing regional folds. 9 Mesoscopic faults at high-angles to bedding . Fig. 3 Defonnational history of the Te Awaiti area, southeastNorth Island. Sketches illustrate the development of structures. S1-S4 are axial surfaces of F CF4 folds. F, .. ",.m",_o~dm,,_I0". _:: 7 F, "."010 ,,,,,. m .. """,,o ond """"""". 10'''. ,~. 6 F 2 isoclinal to tight mesoscopic folds. 5 Regional shearing and disruption via bedding-parallel shears, and cOmpressional and extensional faults at low- and high-angles to bedding. Local development of melange fabric. 4. Extension to produce complex fracture pattems and veins. 3 F 1 isoclinal to gentle mesoscopic folds. 2 Development of extensional (transposition) fabric of unknown areal extent. 1 Syn- or post depositional slump folds (i.e., Pre-tectonic). The structure of Mangapokia Fonnation near Te Awaiti is complex; four generations of tectonic folds (F1-F4) and several episodes of faulting have been recorded (Fig. 2). Exposure is excellent and several macroscopic folds are recognised. Bedding is variably sheared and disrupted, and melange fabric occurs locally. Bedding orientations vary from horizontal through vertical to overturned with gentle dips. Nevertheless, moderately dipping upright beds predominate. The rocks are metamorphosed to at least the zeolite facies of Coombs et al. (1959). A discussion of the mechanisms of stratal disruption and melange fonnation, of the early defonnational history of the rocks, and of a comparison of the structural history at Te Awaiti with structural histories detennined elsewhere in the Torlesse by other workers will be presented elsewhere. The aim of this paper is to undertake a structural analysis of these intensely defonned rocks, including descriptions of the geometry of the mesoscopic and macroscopic structures of Mangapokia Fonnation. Fold description follows Fleuty (1964) and Ramsay (1967). Structural nomenclature follows the standard procedures outlined by Turner & Weiss (1963). The data are plotted on equal area projections (Schmidt nets) and, for many readings, the density distribution was detennined by contouring using the square-grid method of Stauffer (1966). S2-S4 are axial surfaces of folds, not penetrative fabrics. DEFORMATIONAL mSTORY The defonnational history of the Torlesse accretionary wedge near Te Awaiti is summarised in Fig. 3. An early extensional fabric is overprinted by F1 folds that were later dissected by tensional fractures and veins. These early structures were observed in melange inclusions and all predate regional stratal disruption and melange fonnation Barnes (1985). Structures associated with regional disruption include attenuated beds, boundins, "pinch and swell" structure, tectonically elongated conglomerate clasts, lozenge (transposition) fabric, and tectonic melange. The varying states of disruption represent arbitrary stages in a progressive structural continuum. The most defonned sequences reached their fabric via a combination of repeated movement on shears subparallel to bedding, thrusts and nonnal faults at low angles to bedding, and reverse and nonnal faults at high angles to bedding. The melanges are tectonic, rather than sheared, chaotic sedimentary deposits. Tectonic disruption Downloaded by [Univ of Alabama in Huntsville] at 16:27 22 October 2014 Barnes & Korsch-Structure of accretionary wedge, Wairarapa 359 probably occurred through a range of consolidated to semi-indurated physical states by a combination of intergranular flow and cataclasis. Melange units containing exotic ocean-floor (basalt, chert, red and green mudstone) lithologies occur as sheet-like bodies 2-25 m thick. They are inferred to represent basal thrusts of imbricated packets of strata ranging from tens of metres to hundreds of metres thick. Detailed descriptions of the events labelled 2-5 in Fig. 3 will be presented elsewhere. By the end of event 5 (Fig. 3) the rocks consisted of dis-rupted sedimentary sequences and melange (Barnes 1985). The shear foliation in the melange was subparallel to the bedding in the disrupted sedimentary sequences. Thus, at that time, an essentially planar fabric existed, upon which later deformations were superimposed. This factor has enabled us to undertake a classical Turner & Weiss (1963) type structural analysis on these complexly deformed rocks. The sixth event (Fig. 3) was the formation of isoclinal to tight, predominantly asymmetric, mesoscopic F* folds that developed after the initial pervasive disruption ot strata, but during continued accretion and imbrication of thrust-bound packets. The first six events in Fig. 3 produced structural fabrics typical of sediments deformed in accretionary wedges (Barnes 1985), and they are inferred to have occurred during middle Cretaceous subduction. Later events produced structures common in late Cenozoic sequences in eastern North Island, and they are probably Late Tertiary and Quaternary responses to the present convergent regime at the Hikurangi Margin (pacific-Australian plate boundary). FOLDING Pretectonic structures are rare, being represented mainly by soft-sediment slump folds within channel-fill, matrix-supported conglomerate facies. Some tight folds in sandstone layers appear to "float" within a coarse-grained sandy matrix, and small, tight folds in horizontally laminated sandstone fragments are ripped up and incorporated into pebbly mud-stone (Barnes 1988). Mesoscopic tectonic folds are abundant and most commonly developed in thin- to medium-bedded alternating sandstone and mudstone facies and thin conglomerate beds. In contrast, thick-bedded sandstone units are rarely folded mesoscopically, and in facies with high mudstone contents, shear-related structures predominate. Four generations of tectonic folds are recognised. One generation predates formation of melange, and three postdate the melange. Photographs of the folds will be presented elsewhere, and for full descriptions of them refer to Barnes (1985). Only a brief summary will be presented here. Rare, premelange, mesoscopic Fl folds occur within discrete melange fragments. The folds developed in bedding that displays various stages of extensional, fault-controlled disruption, ranging from attenuated but relatively coherent to thoroughly disrupted fabrics. The folds have limbs truncated by shear-foliation within the surrounding argillaceous melange, suggesting that they developed prior to the inclusions being incorporated within the melanges. F2 folds are extremely numerous and also have been recognised only on a mesoscopic scale. They postdate the completion of regional stratal disruption and melange development (Fig. 3). The folds have variable style with interlimb angles ranging from about 85 to isoclinal. Inclined, gently plunging folds predominate, and upright, gently to moderately plunging folds are less numerous. F3 folds are common throughout the area, and in many exposures are the dominant mesocopic structures. Macroscopic F3 folds are common, and hinge regions can be traced for up to 1 km (Fig. 2). The folds occur in all lithologies, have variable style, and refold and overprint F2 structures. The melange zones are also folded by this phase. Generally they are more open and less asymmetric than F2, and usually differ significantly in orientation from overprinting, F4 structures. Upright to steeply inclined, subhorizontal to moderately plunging folds predominate. They are nearly coaxial with F2, and locally are developed on the overturned limbs of F 2 structures. Hence, they include synclinal antiforms and anticlinal synforms. Mesoscopic F4 folds are best developed and most easily identified in the east where their axial traces are oriented at high angles to the regional bedding trend (Fig. 2). The folds refold and overprint F 2 and F 3 structures, and also are locally developed on the overturned limbs ofF2 folds. GEOMETRIC ANALYSIS Fl folds are superimposed on an early broken formation and were observed within fragments in melange produced during regional pervasive disruption. The fragments are surrounded by penetratively sheared argillaceous matrix and were probably rotated and translated significantly during the formation of the melanges. Hence the orientations ofF 1 folds and associated fractures are now meaningless in terms of a geometric analysis. The F2, F3, and F4 fold events are superimposed upon an extensional fabric (S r). They developed after regional disruption and melange formation, and their present orientations have been analysed. Four, small coastal areas are described in detail, followed by a macroscopic geometric analysis for the whole area. Exposure in each detailed area is sufficient to allocate most mesoscopic structures to fold generations on the basis of overprinting relationships alone. Correlation of structures between areas then allows examination of the style changes between different fold generations, the variations within single generations, and the orientation patterns of different structures. Thus, the method is useful for unravelling the structural complexity of the whole Te Awaiti area. In each detailed area studied, sandstone beds are variably attenuated and fragmented, contacts between sandstone and mudstone lithologies are commonly sharp, and most mudstone units have been intensely sheared and preferentially eroded out Area A Area A represents about 600 m2 Of coastal platform at G.R. S28B/2392651O (grid references refer to the NZMS 260 map series) (Fig. 4). Well-bedded, alternating sandstone and mudstone, with an average bed thickness of 100-150 mm have undergone at least two periods of folding (F2 and F3). The exposure is dominated by a refolded F 2 fold. F 2 axial surface traces are refolded by gentle to open F3 folds whose subvertical axial surfaces trend northeast-southwest. The F2 folds are asymmetric, tight to isoclinal, and S-shaped with overturned short limbs. Poles to axial surface of the F 2 folds (S2) define a partial great circle girdle, indicating that S2 has been folded cy lindrically about a 1t-axis (B~ ~ ) oriented 30 to 040. Downloaded by [Univ of Alabama in Huntsville] at 16:27 22 October 2014 360 A \ ~\ B \ ~\ '.'-0 '\ \. ___________________ F c N ~-~.'\ /0\ . \ i. '.' .. ' ..... / \. J \" .... '------'- " ----------_/ 144 x S, 1, 3, 10, 20 , r !" New Zealand Journal of Geology and Geophysics, 1990, Vol. 33 _!l._ So (+Dverturned) --------- Axial surface trace , , z,.~ /10 I 1 , , r ~ I lOj I ,. J '38 ~J7 lSI f 1 f ! lS! ,I , " '1, , 21 'i, ~35 1 \ , , 30 I 1)6 "t, t" i" t t 1 f I r , t30 f 2"'- F2 fold axis 3S+--t F3 fold aXIs - - - - Axial surface 52 -.-.- Axial surface S3 N ... ; . Fig.4 Form surface structural map (A), map of distribution offold axes and axial surfaces (B), and equal area projections (C) of structural components at area A (G.R. S28B/23926510; see position on Fig. 2). Numbers on the lower left comer of stereonets represent the number of observations; numbers on lower right are the contour interval in % per 1 % area. Downloaded by [Univ of Alabama in Huntsville] at 16:27 22 October 2014 Barnes & J(orsch-Structure of accretionary wedge, Wairarapa 361 N (0.5). 2. 4. 6. 8 N \. ~ .. 18 7t S ...... . . " :.: ~ + 18 s:: Folds .. 0 F. c: ~ "' 4 CJ ~ '.:: ;': ~' . F. .. .. .0 3 0 ~ 0 0-.. .0 E I :> Z 30 60 90 120 ISO Interlimb angle (dog, ... 1 A 180 - Bedding (Sol - - - - Axial surface S 3 H ,. F3 fold axis .-._ Axial surface S. -=v- Fault -L.. Strike and clp of bedding 10 20m .... -== .... -=:::::::::ll . '\: ... + 30 sf: ..... ~ '. ~ , ....... ...-.~ l/~ , / )i' 31 7t S. ..,..> ..... Fig. 5 Fonn surface structural map, equal area projections of structural components, and interlimb angles of F 3 and F4 folds in area B (G .R. S28B/26346620; see position on Fig. 2). Positions of F4 warps not shown on map. Numbers on the lower left comer of stereonets are the number of observations; numbers on the lower right are the contour interval in % per 1 % area. All F3 folds plunge gently or moderately to the northeast and are mainly symmetrical, reflecting their position close to the hinge region of a macroscopic F3 fold (Fig. 2). Hence they can be distinguished from F2 on the basis of style and orientation of axial surfaces. The small spread in orientation of F3 fold axes (B ~]) and axial surfaces (S3) reflect small variations in the orie~tation of So prior to the F3 event. Poles to So defme a partial great circle girdle (Fig. 4). The 1t-axis is oriented 32 to 046, and coincides with both the F2 and F3 fold axes. The spread of bedding is similar to that of the S2 axial surfaces and reflects the F3 event. AreaB Area B (Fig. 5) represents a 4500 m2 segment of coastal platform 1.1 kIn east of the Oterei River mouth (Fig. 2). Here, alternating sandstone and mudstone have been deformed by at least two periods of folding (F3 and F4). Rare younging directions suggest an upright sequence. Axial traces of the predominantF3 folds trend northeast-southwest, and those of F4 trend northwest-southeast (Fig. 5). Poles to So define a great circle girdle with a 1t-axis oriented 12 to 033. F3 folds are slightly asymmetrical with subvertical axial surfaces, and interlimb angles ranging from 40 to 156 Downloaded by [Univ of Alabama in Huntsville] at 16:27 22 October 2014 c A '" c: o :;:: t ~ .D o mF, OF, OF, OJ .0, l:i z: lO B 60 90 120 lnterlimb angle (d ,s) \So 'BO/~ ~/~ ~~~ ~,~ ?': 74~~~'~"~ /. '4~ ~.Ifi'~~~\~~ ' '~~ --~ " "Til' , /,1/ '1:" < ---~ ""'--.... ------~ U ( l I. /I ..... ~-.;---..,.-"--' , ~II(I'-"-'~-~" .~ .... " "" '----...... ,,' -..-3-:.=:. ~-:!.~ ~\. """"-/_" ~ ,.~.~=---4.~'" ,-~-,.. -+~ ~.:,,-:::~~~:.-7' .. ~~r~'~'~";;':~ ",:::==--/~-.-, ~ ,-,-~ _--:--~, I ~ ~~-~~~ I ~_,,~~~~,\~J ~~ .... ~ -=="'" -___ .,~~'S~ '\.., -. ,,,~\\\~~' ~ w w Downloaded by [Univ of Alabama in Huntsville] at 16:27 22 October 2014 \\ '-'-'~~ ~~~----.::::::-~-~ ---" ------=-==----==-~ -== .;:::::::; '::"':1;"") L ~ 2 .;;:..-~ /'$ ~ .. ---~ ~\\~~~~~ ----===--==---~ 2-::"~~ .......... ~~ ....... -'=-~ ~ ~~/~~-~ ~-=-~ ____ ~~ ~-~-2 -.--::::::---s...-F~\"" ~~l;~---~:::~ \~, ~,,-',X' \ __ -~ _ 11/(~;;'\\~0~\\t'. ~-~ ~~\~ 1~~~\:\\\\\\I/ ~J?:: ~ ~'-......! -,,::-\\ ...:::::::-- /:/ --::: \ ~ I~ -~/ Ijf ~' f!J 4/.,// 2,/'I?i:~d~fhJ~ I 1\\1 ?~~~~-:\!IP;JP II ~~~l~~ , ~~Wif~~'4 /I; -__ ~~7 l"-~":=~ ~ :-\ i> .. ~-' ", !L:-" .L_ .. J Symbols for inset figures.. Younging defined at outcrop ... Younging Inferred from structural relationships S. axial surface trace S. axial surface trace S. axial surface trace ~ Fau~',~, I ~< ~'~~ ~;;,.,-2 ~'r-:;\~:..r'((;~ij2' l~). z~t;.",,.:-, ,(.='\.~ ~l.\\" ~~~j L-Jm~~'X \~~., . J'\\~\j\" 11/ ((1/ J/ '.~ / ;i:: I~f,,' , (I'(;t,/: 11/ . '/'/111 11/11 I!LI !/,I I (~ N\ FIg.13 Fonn surface structural map of the Waikowhai Stream. (Part of domain 4.) Inset figures, sketched from photographs, show various overprinting relationships.f1-'\ E:J tJ:j a ~ ?'> ~ I ~ ~ fa, i c)" ~ ~ ~ .0 ~ ~. i W ...J W Downloaded by [Univ of Alabama in Huntsville] at 16:27 22 October 2014 374 New Zealand Journal of Geology and Geophysics, 1990, Vol. 33 N + 83 Axial planes B S 4 Axial planes c Fig.14 Synoptic equal area projections for domains 1-12 in the Te Awaiti area. (e.g., Mosher & Helper 1988). Their orientations were controlled by the previously intensely deformed, irregular bedding surfaces, rather than by a different orientation of the major stress field during F4. Thus the Torlesse accretionary wedge in the Te Awaiti area has had a complex structural history during Cretaceous subduction and accretion that has been further complicated by a later episode of convergent tectonics in the late Cenozoic. ACKNOWLEDGMENTS _ This research was undertaken through the Research School of Earth Sciences at Victoria University of Wellington, between 1983 and 1986. We thank Dan May, Ian Wright, John Bradshaw, and Paul Williams for constructive comments on the manuscript. New Zealand Oceanographic Institute staff Fiona Berry typed the manuscript, and Karl Majorhazi drafted the figures. REFERENCES Barnes, P. M. 1985: Sedimentology, petrology, and structure of Mangapokia Formation (Pahaoa Group) near Te Awaiti, southeast Wairarapa, New Zealand. Unpublished M.Sc. thesis, lodged in the Library, Victoria University of Wellington. 256 p. ---1988: Submarine fan sedimentation at a convergent margin: the Cretaceous Mangapokia Formation, New Zealand. Sedimentary geology 59: 155-178. ----1990: Provenance of Cretaceous accretionary wedge sediments: the Mangapokia Formation, Wairarapa, New Zealand. New 'kaland journal of geology and geophysics 33: 125-136. Coombs, D. S.; Ellis, A. J.; Fyfe, W. S.; Taylor, A. M. 1959: The zeolite facies with comments on the interpretation of hydrothermal syntheses. Geochimica et cosmochimica acta 17: 53-107. Eade, J. V. 1966: Stratigraphy and structure of the Mount Adams area, eastern Wairarapa. Transactions of the Royal Society of New 'kaland geology 66: 103-117. Fluety, M. J. 1964: The description of folds. GeologicalAssociation proceedings 75: 461-492. George, A. D. 1988: Accretionary prism rocks of the Torlesse terrane, western Aorangi Range--Cape Palliser, New Zealand. Unpublished Ph.D thesis, lodged in the Library, Victoria University of Wellington. 184 p. Ghani, M. A. 1978: Late Cenozoic vertical crustal movements in the southern North Island, New Zealand. New Zealand journal of geology and geophysics 21: 117-125. Hobbs, B. E.; Means, W. D.; Williams, P. F. 1976: An outline of structural geology. New York, Wiley International. 571 p Kingma, J. T.1967: Sheet 12-Wellington. Geological map of New Zealand 1:250000. Wellington, New Zealand. Department of Scientific and Industrial Research. Korsch, R. J.; Wellman, H. W. 1988: The geological evolution of New Zealand and the New Zealand region. In: Nairn, A. E. M.; Stehli, F. G.; Uyeda, S. ed. The ocean basins and margins. Vol. 7B. Plenum Publishing Co. Pp. 411-482. Moore, P. R.; Speden, I. G. 1979: Stratigraphy, structure, and inferred environments of deposition of the Early Cretaceous sequence, eastern Wairarapa, New Zealand. New 'kaland journal of geology and geophysics 22: 417-433. ----1984: The Early Cretaceous (Albian) sequence of eastern Wairarapa, New Zealand. New Zealand Geological Survey bulletin 97: 97 p. Mosher, S.; Helper, M. 1988: Interpretation of poly-deformed terranes. In: Marshak, S.; Mitra, G. ed. Basic methods of structural geology. Part II, Special topics. New Jersey, Prentice Hall. pp. 361-384. Pettinga, J. R. 1982: Upper Cenozoic structural history, coastal Southern Hawke's Bay, New Zealand. New Zealandjournal of geology and geophysics 25: 149-191. Downloaded by [Univ of Alabama in Huntsville] at 16:27 22 October 2014 Barnes & Korsch-Structure of accretionary wedge, Wairarapa 375 Fig. 15 Simplified Cretaceous-Cenozoic structure and stratigraphy in the Te Awaiti-White Rock region, and position of this study area (Fig. 2). Lithological contacts from Moore & Speden (1984). Neocomian Torlesse terrane inferred from George (1988). Mp, PiripauanStage; L, Landon Series; Tt, Tongaporutuan Stage; Tk, Kapitean Stage; W, Wanganui Series; Wo, Opoitian Stage; Wn, Nukumaruan Stage. TI-W Ramsay, 1. G. 1967: Folding and fracturing of rocks. New York, McGraw Hill Co. 586 p. Singh, L. 1. 1971: Uplift and tilting of the Oterei coast, Wairarapa, New Zealand, during the lastten thousand years. In: Collins, B. W.; Fraser, R. ed. Recent crustal movements. Royal Society of New Zealand bulletin 9: 25-30. Sp6rli, K. B.; Ballance, P. F. 1989: Mesozoic/Cenozoic ocean floor/ continent interaction and terrane configuration, southwest Pacific area around New Zealand. In: Ben Avraham, Z. ed. Mesozoic and Cenozoic evolution of the Pacific Ocean margins. Oxford University monograms, geology and geophysics 8: 176-190. Stauffer, M. R. 1966: An empirical-statistical study of three-dimensional fabric diagrams as used in structural analysis. Canadian journal of earth sciences 3: 473-498. Turner, F. 1.; Weiss, L. E.1963: Structural analysis of metamorphic tectonites. New York, McGraw Hill Co. 545 p. o I pm OCEAN O Late (Calcaroous mudstona, limastona) Late Cretaceous--IImI Oligocene (Limastona, 11!211 glauooni1lc sandstona, shala, benton~a) middle-Late Cretaceous (Braccia-conglomerats, sandstonalsilt 51ona) Early-middle D creraceous accreticlnrurvl Torlesse terrane (pm, Mangapokia Fmn) Principle Late -- Cenozoic faults ~ Inferred Early Miocene thrust +t Late Cenozoic folds #F, F3 folds; this study 4km I + 1 Walcott, R. I. 1984: Reconstructions of the New Zealand region for the Neogene. Palaeogeography, paleoclimatology, palaeoecology 46: 217-231. ----1987: Geodetic strain and the deformational history of the North Island of New Zealand during the late Cainozoic. Philosophical transactions ofth Royal Society of London A321: 163-181. Waterhouse, 1. B.; Bradley, 1. 1957: Redeposition and slumping in theCretaceo-TertiarystrataofS.E.Wellington.Transactions ofth Royal Society of New 'ZBlland 84: 519-548. Wellman, H. W. 1971: Holocene tilting and uplift on the Glenburn coast, Wairarapa, New Zealand. In: Collins, B. W.; Fraser, R. ed. Recent crustal movements. Royal Society of New 'ZBlland bulletin 9: 221-223. Williams, P. F. 1970: A criticism in the use of style in the study of deformed rocks. Geological Society of America bulletin 81: 3283-3296. ----1985: Multiply deformed terrains-problems of correlation. Journal of structural geology 7: 269-280. Downloaded by [Univ of Alabama in Huntsville] at 16:27 22 October 2014


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