Hautotara, Te Muna and Ahiaruhe Formations, middle to late Pleistocene, Wairarapa, New Zealand

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<ul><li><p>This article was downloaded by: [University of Prince Edward Island]On: 21 November 2014, At: 06:16Publisher: Taylor &amp; FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK</p><p>Journal of the Royal Society ofNew ZealandPublication details, including instructions for authors andsubscription information:http://www.tandfonline.com/loi/tnzr20</p><p>Hautotara, Te Muna and AhiaruheFormations, middle to latePleistocene, Wairarapa, NewZealand.J. D. Collen &amp; P. Vella aa Department of Geology , Victoria University ,WellingtonPublished online: 05 Jan 2012.</p><p>To cite this article: J. D. Collen &amp; P. Vella (1984) Hautotara, Te Muna and AhiaruheFormations, middle to late Pleistocene, Wairarapa, New Zealand., Journal of the RoyalSociety of New Zealand, 14:4, 297-317, DOI: 10.1080/03036758.1984.10421732</p><p>To link to this article: http://dx.doi.org/10.1080/03036758.1984.10421732</p><p>PLEASE SCROLL DOWN FOR ARTICLE</p><p>Taylor &amp; Francis makes every effort to ensure the accuracy of all the information(the Content) contained in the publications on our platform. However, Taylor&amp; Francis, our agents, and our licensors make no representations or warrantieswhatsoever as to the accuracy, completeness, or suitability for any purposeof the Content. Any opinions and views expressed in this publication are theopinions and views of the authors, and are not the views of or endorsed byTaylor &amp; Francis. The accuracy of the Content should not be relied upon andshould be independently verified with primary sources of information. 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Terms &amp; Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions</p><p>Dow</p><p>nloa</p><p>ded </p><p>by [</p><p>Uni</p><p>vers</p><p>ity o</p><p>f Pr</p><p>ince</p><p> Edw</p><p>ard </p><p>Isla</p><p>nd] </p><p>at 0</p><p>6:17</p><p> 21 </p><p>Nov</p><p>embe</p><p>r 20</p><p>14 </p><p>http://www.tandfonline.com/page/terms-and-conditionshttp://www.tandfonline.com/page/terms-and-conditions</p></li><li><p> Journal of the Royal Society of New Zealand, Volume 14, Number 4, 1984, pp. 297-317 </p><p>Hautotara, Te Muna and Ahiaruhe Formations, middle to late Pleistocene, Wairarapa, New Zealand. </p><p>J. D. Collen and P. Vella* </p><p>The Hautotara, Te Muna and Ahiaruhe Formations are formally described for the first time. The Hautotara Formation contains the littoral marine and estuarine deposits of the Huangarua Cyclothem together with underlying freshwater deposits which have been added for mapping convenience, and is considered to be late Marahauan (c. 1.2 to 1.05 Myr) in age. The Te Muna Formation is a conformable sequence, 366 m thick, containing fifteen members. Alluvial gravels alternate with freshwater blue-grey silt and sand with lignite layers, tree roots in growth position and occasional paleosols. The Te Muna Formation also contains loess at one horizon, and localised rhyolitic tephra beds. The tephras and preliminary paleomagnetism indicate a Castlecliffian age (c. 1.0 to 0.4 Myr). The Ahiaruhe Formation consists of alluvial gravel varying from a few metres to more than 80 m in thickness, interbedded with water-laid, partly loessic silts locally containing Mount Curl Tephra (c. 0.23 0.04 Myr; equals Ahiaruhe Tephra). It has a tilted but still well-defined depositional surface at the top forming terraces, and passes laterally westward to thick blue-grey lacustrine silt with a moa footprint and also containing Mount Curl Tephra. The tephra indicates an age greater than 0.2 Myr for the the base of the Ahiaruhe Formation and less than 0.26 Myr for the top. Kawakawa Tephra in overlying loess indicates an age greater than 0.02 Myr. The three formations correspond to most of the time represented by the late Nukumaruan Stage, Castlecliffian Stage and early Hawera Series. We infer that their deposition was controlled by climatic fluctuations and associated glacio-eustatic sea-level changes coincident with Milankovitch cycles, superimposed on secular vertical tectonic movements. </p><p>Keywords: Ahiaruhe Formation, Hautotara Formation, Milankovitch cycles, Pleistocene, sea-level changes, stratigraphy, Wairarapa. </p><p>INTRODUCTION The lithostratigraphic names Hautotara Formation, Te Muna Formation and Ahiaruhe </p><p>Formation have been used for some time in manuscripts and on unpublished maps. The Hautotara Formation, the lowest of the three, disconformably overlies Pukenui Limestone Formation (Vella and Briggs, 1971) and consists offreshwater, estuarine and near-littoral marine deposits. The Te Muna Formation overlies Hautotara Formation with slight angular unconformity, overlapping on to Pukenui Limestone, and consists entirely of freshwater deposits. The Ahiaruhe Formation unconformably overlies Pukenui Limestone and older strata at various places, but has not yet been shown to overlie Te Muna or Hautotara formations. It consists mainly of freshwater deposits with some loessic components. </p><p>The type sections and and most studied area of Hautotara and Te Muna formations are in the Huangarua Syncline (new name), a northeast-trending structure that obliquely crosses the Huangarua Valley a few kilometres southeast of Martinborough town (Figs. 1, 2). The Huangarua Syncline is an asymmetrical box-fold that is probably draped over block-faulted Mesozoic basement. The axis lies close to its northwest side, which is defined by steep southeastward dips in Te Muna, Hautotara and older formations </p><p>Department of Geology, Victoria University, Wellington. </p><p>Dow</p><p>nloa</p><p>ded </p><p>by [</p><p>Uni</p><p>vers</p><p>ity o</p><p>f Pr</p><p>ince</p><p> Edw</p><p>ard </p><p>Isla</p><p>nd] </p><p>at 0</p><p>6:17</p><p> 21 </p><p>Nov</p><p>embe</p><p>r 20</p><p>14 </p></li><li><p>298 Journal of the Royal Society of New Zealand, Volume 14, 1984 </p><p>Fig. i-Locality map. </p><p>Fig. 2 -Geological map for Hautotara and Te Muna formations in type area along Huangarua River. Pre-Hautotara geology and structure simplified for clarity. </p><p>DVounger alluvium ~&gt;::::;:J Te Muna Formation </p><p>13~,;:;o~Ahiaruhe Formation _Hautotara Formation ~-.P"5iiiiP"'Iii </p><p>r7:':1Pukenui Lmst. Fmn. ~ (LOWER PLEISTOCENEi r_-_-_-_JGreycWs Formation &amp; ---_-_-_ Mangoopon Mst. Fmn. </p><p>(PLIOCENE-lwr PLEISTOCENE) </p><p>"m GRID TAKEN FROM NZMS 260 SHEET S 27 </p><p>Dow</p><p>nloa</p><p>ded </p><p>by [</p><p>Uni</p><p>vers</p><p>ity o</p><p>f Pr</p><p>ince</p><p> Edw</p><p>ard </p><p>Isla</p><p>nd] </p><p>at 0</p><p>6:17</p><p> 21 </p><p>Nov</p><p>embe</p><p>r 20</p><p>14 </p></li><li><p>Collen, Vella - Hautotara, Te Muna and Ahiaruhe Formations 299 </p><p>exposed in the banks of the Huangarua River within and immediately south of the Huangarua Fault Zone (Fig. 2). The southeastern margin of the syncline is defined by a monoclinal flexure 1.5 to 2 km distant from the axis. Here Pukenui Limestone, Hautotara and Te Muna formations all dip at high angles, commonly 45 a and locally even 70 0 . Erosion of soft Hautotara Formation from resistant Pukenui Limestone has formed a linear scarp along the monocline, but no evidence of faulting has been found. Between the monocline and the axis of the syncline Te Muna Formation dips gently northwestward at about 100 near the monocline, reducing gradually to zero at the axis. The monocline was probably formed by folding of Cenozoic strata over faulted Mesozoic basement rocks. </p><p>The Hautotara Formation and most of the Te Muna Formation are weakly consolidated, and form a subdued landscape with few exposures except along the Huangarua River. Some conglomerate layers in the Te Muna Formation are locally firmly cemented by iron oxides (the "ferruginous conglomerates" of McKay, 1879) and stand out prominently on hillsides, but the cementation is not persistent enough to enable them to be mapped continuously. Exposures in the banks of the Huangarua River are discontinuous, but because the river meanders and runs very obliquely across the strike of the southeast flank of the syncline, it has been possible to reconstruct almost the entire section with only one substantial unexposed interval in the upper part of the Te Muna Formation. </p><p>HAUTOTARA FORMATION The term Hautotara beds was used by Hector (1884) without definition for blue-grey </p><p>silts, grits and conglomerates at Manawatu Gorge which he correlated with beds at Hautotara. As now defined, the name probably represents a more restricted usage than that of Hector. </p><p>Most of the Hautotara Formation is the Huangarua Cyclothem (Vella, 1963). For mapping convenience it has usually been found best to take the highest cemented coquina bed as representing the top of the underlying Pukenui Limestone Formation (Vella and Briggs, 1971). Consequently, at Hautotara (junction of the Ruakokopatuna and Makara Rivers), freshwater strata that were treated as part of the Eringa Cyclothem (Vella, 1963), which approximately corresponds to Pukenui Limestone, have been mapped as the lower part of the Hautotara Formation (Fig. 3). </p><p>The type section of the Hautotara Formation is the same as for the uppermost Eringa Cyclothem plus the Huangarua Cyclothem. It extends along the east bank of the Huangarua River for a distance of 400 m downstream from the junction of the Ruakokoputuna and Makara Rivers (marked by Banana Bridge on White Rock Road). The sequence is shown by Vella (1963, fig. 3). The original description of the Huangarua Cyclothem is here supplemented (Fig. 3) with data from Rodley (1961) who measured and described with great care that part of the section that was visible to her. The freshwater beds at the top of the Eringa Cyclothem described by Vella (1963) were mostly covered by earthworks during construction of Banana Bridge. In addition, successful river conservation work has diverted the river from the east bank downstream from Banana Bridge, so that much of the section here is now overgrown. It is still the most complete section known through the formation, however, and it is fortunate that the earlier descriptions are available. </p><p>Relationship with underlying Pukenui Limestone Formation The contact between Hautotara Formation and Pukenui Limestone Formation has </p><p>been seen clearly at only one place, on the east bank of the Huangarua River 1 km south of Te Muna (S27/18658850; Metric grid references are taken from NZMS 260 Sheet S27, Martinborough (1st Edition, 1980)). There, unconsolidated gritty calcareous sand of Hautotara Formation rests on a solution-pitted surface of hard Pukenui Limestone. Scattered well-rounded pebbles and cobbles of Meozoic sandstone, and occasional worn and bored calcareous concretions from underlying late Cenozoic formations lie on the limestone surface but are not cemented to it; and the limestone at that site contains no </p><p>Dow</p><p>nloa</p><p>ded </p><p>by [</p><p>Uni</p><p>vers</p><p>ity o</p><p>f Pr</p><p>ince</p><p> Edw</p><p>ard </p><p>Isla</p><p>nd] </p><p>at 0</p><p>6:17</p><p> 21 </p><p>Nov</p><p>embe</p><p>r 20</p><p>14 </p></li><li><p>300 Journal of the Royal Society of New Zealand, Volume 14, 1984 </p><p>en Q) L. -Q) E </p><p>TE MUNA FORMATION </p><p>4O-i-~ Co" " .......... ..1 ~cross-bedded sands with Chione shellbed .... ':.: ... : .. ':.:'; In basal metre </p><p>----........... </p><p>30-1::: :::: ::::: </p><p>20 </p><p>bored contact Fig.6 </p><p>contact nof exposed </p><p>Zethalia sands- coarse, well sorted, friable brown sandstone Fig.5 </p><p>~~ ,"".Iome,ot. w;1\, wom T .w'" volve. .~.:.i.;.?.:: interbedded silts, sands and peat with ;;;;;;;;;;;; basal conglomerate </p><p>lO'~.;;c;,;;o:,; . </p><p>o~ </p><p>argillaceous sandstone with well preserved bivalves </p><p>PUKENUI LIMESTONE FORMATION </p><p>z o ~ ~ a::: o u. </p><p> a::: b ~ :::&gt; :::r: </p><p>Fig. 3 - Stratigraphic column of Hautotara Formation, Huangarua River. Data from Rodley (1961) and Vella (1963). </p><p>large clasts. The contact is evidently an erosion surface. Four kilometres to the northeast, a deeply incised creek flowing from Windy Peak to the Huangarua River exposes a section at the base of the monocline on the southeast side of the Huangarua Syncline. There, the contact is marked by a creamy-white clay about 100 mm thick, which is considered to be a paleosol indicating terrestrial weathering probably without significant erosion. In the type area the contact is probably at least a minor disconformity, because during a change from marine to freshwater conditions, continuity of deposition, whether due to progradation or to a change in relative sea-level, requires unusual circumstances (Vella, 1963). </p><p>Everywhere that Hautotara Formation has been found it is underlain by upper Pukenui Limestone, and there is evidently little or no angular discordance. We consider that the contact is usually a disconformity probably representing only a slight time intervaL </p><p>Dow</p><p>nloa</p><p>ded </p><p>by [</p><p>Uni</p><p>vers</p><p>ity o</p><p>f Pr</p><p>ince</p><p> Edw</p><p>ard </p><p>Isla</p><p>nd] </p><p>at 0</p><p>6:17</p><p> 21 </p><p>Nov</p><p>embe</p><p>r 20</p><p>14 </p></li><li><p>Collen, Vella-Hautotara, Te Muna and Ahiaruhe Formations 301 </p><p>Fig. 4- Weathered outcrop of Zethalia sand member of Hautotara Formation in type section. Photo shows well sorted, friable sandstone with abundant Zethalia. Hammer Length is 327 mm. </p><p>Fig. 5 - Barytellina siltstone member of Hautotara Formation in type section, showing paired valves of Barytellina anomalodonta. Photo width 0.4 m. </p><p>Dow</p><p>nloa</p><p>ded </p><p>by [</p><p>Uni</p><p>vers</p><p>ity o</p><p>f Pr</p><p>ince</p><p> Edw</p><p>ard </p><p>Isla</p><p>nd] </p><p>at 0</p><p>6:17</p><p> 21 </p><p>Nov</p><p>embe</p><p>r 20</p><p>14 </p></li><li><p>302 Journal oj the Royal Society oj New Zealand, Volume 14, 1984 </p><p>Distribution Hautotara Formation has been mapped for a distance of6 km northeast from the type </p><p>locality as a narrow linear strip along the base of the monocline scarp at the southeast side of the Huangarua Syncline (Fig. 2). It has also been identified underlying Te Muna Formation and overlying Pukenui Limestone over a distance of 4 km along Blue Rock Stream from its junction with Ruakokopatuna River, 4 km southwest of the type locality. An isolated exposure of grey silts with estuarine fossils (Chione, Modiolus) interbedded in alluvial conglomerate in Whangaehu Stream (S27/23509410), about 1 km north of Popes Head, may be Hautotara Formation. </p><p>At the growing Gladstone Anticline (Kennett, 1964), 27 km north-northeast of the type locality, the upper part of Gladstone Formation, consisting of freshwater (lignite-bearing) silts and overlying richly fossiliferous marine brown-grey, cross-bedded sands (Kennett, 1964), are here considered to represent Hautotara Formation. We have mapped the underlying part of the Gladstone Formation as upper Pukenui Limestone Formation. We consider that the weakly consolidated, sandy, well-rounded conglomerate and fossiliferous sand overlying Pukenui Limestone, probably with a strong on-lap contact, on the western flank of Maungaraki Range east and northeast of Gladstone are also Hautotara Formation. </p><p>Marine sands containing Chione stutchburyi and interbedded with conglomerate in the western foothills of the Aorangi Range (S27/01288655), east of Lake Wairarapa, m...</p></li></ul>


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