The Diverse Crustal Structure and Magmatic Evolution of the Manihiki Plateau, Central Paciﬁc K

Home , Manihiki Plateau

Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 2 ) marine and terrestrial areas erent magmatic and tectonic 2 ff km , and R. Werner 6 1 10 × 0.1 > 1864 1863 , G. Uenzelmann-Neben 1 , K. Gohl 1 wave velocity distribution, which is comparable to other LIPs. The High P This discussion paper is/has beenPlease under refer review to for the the corresponding journal final Solid paper Earth in (SE). SE if available. Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Am Alten GEOMAR Helmholtz-Zentrum für Ozeanforschung, Wischhofstr. 1–3, 24148 Kiel, Germany impact on therelease environment of during greenhouse and gases after during their massive emplacement, volcanism for (Wignall, instance 2001) or by their the role Plateaus underwent crustal stretchingNui. during This and indicates, after thatpart the in the break-up the sub-plateaus break-up of history of Ontong of the Java Ontong Java Manihiki Nui. Plateau play an1 individual Introduction Large Igneous Provinces (LIP) areoverprinted large ( by massive volcanic activity (Bryan and Ernst, 2008) LIPs have a great sive secondary volcanism and arebasins. mainly A structured by constant fault decrease systemsstretching in and on Moho sedimentary the depth Western Plateaus. (9–17 km)sub-plateaus Those findings is of lead a to the further the Manihikihistory. conclusion, indicator that Whereas Plateau of the the experienced crustal two High a Plateau di experienced a secondary volcanism, the Western therefore decipher the break-upafter mechanisms its as initial emplacement. well Byprofiles as crossing analyzing the the two two evolution seismic largest of sub-plateaus refraction/wide-angleand of reflection the the the Western plateau Manihiki Plateau, Plateaus, thematic we High evolution. give Plateau new The insights Higha into Plateau seismic their shows crustal a structurePlateau crustal and experienced structure mag- a of strongseamount 20 km chain secondary volcanism. thickness volcanism, The and which Western can Plateaus be on the seen other in hand relicts show of no exten- The Manihiki Plateau isemplaced a as Large part Igneous ofinto the Province “Super-LIP” three (LIP) Ontong sub-plateaus, in Java possibly the Nuihiki during central and Plateau the is experienced Pacific. presumably break-up fragmentation It the of was centerpiece Ontong of Java this Nui. “Super-LIP” and The its Mani- investigation can Abstract 1 Hafen 26, 27568 Bremerhaven,2 Germany Received: 7 July 2014 – Accepted: 10Correspondence July to: 2014 K. – Hochmuth Published: ([email protected]) 25 July 2014 Published by Copernicus Publications on behalf of the European Geosciences Union. The diverse crustal structure and magmatic evolution of the Manihiki Plateau, central Pacific K. Hochmuth Solid Earth Discuss., 6, 1863–1905,www.solid-earth-discuss.net/6/1863/2014/ 2014 doi:10.5194/sed-6-1863-2014 © Author(s) 2014. CC Attribution 3.0 License. 5 25 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | erent petrolog- ff n, 2004; Wignall, 2001) and ffi n et al., 2006; Ridley and Richards, ffi n et al., 2006; Courtillot et al., 1999; ffi cult to date, since the complete activity ffi 1866 1865 wave velocities, mafic intrusions in the middle crust, P n et al., 2006, 2002; Courtillot et al., 1999; Korenaga, 2005; n and Eldholm, 1993; Ingle and Co ffi ffi erent mantle sources. Seafloor spreading was established possibly around 118 Ma The Manihiki Plateau itself experienced fragmentation into three sub-plateaus, the In this paper, we try to unravel the relationship between the two largest sub-plateaus ff High Plateau, the(Fig. Western 1). Plateaus Further and significant the features North of Plateau the (Winterer Manihiki et Plateau al., are 1974) the Danger Island in Ellice BasinTrough (Ontong (Hikurangi–Manihiki) Java–Manihiki) (Worthington (Chandler etof et al., seafloor-spreading al., at 2006). 2012) both Theof and locations onset those at is and spreading-centers di the the hasriod. Osbourn Therefore, duration occurred no magnetic within seafloor-spreading thechanges anomalies in can Cretaceous the be magnetic Magnetic traced, field and cannot Quieting smaller be (Billen Pe- observed and due Stock, to 2000). the severe volcanic overprint- with smaller eruption ratesical and mainly and seamount geochemical volcanism, characteristics shows2010; on di Timm the et three al., remainingment 2011). plateaus of This (Hoernle the led et to plateaus,di al., the the conclusion, multiple that stages after of the secondary coupled emplace- volcanism were supplied by The formation of the120 Ma) Manihiki as Plateau centerpiece took ofand the place Chandler “Super-LIP” et during Ontong al. Java (2012, the Nui 2013). earlyand This according giant Ernst, to Cretaceous LIP 2008; Taylor covered (2006) (123– Co 0.8 % ofconsisted Earth’s of surface the (Bryan Ontong Java(Fig. Plateau, the 1 Hikurangi (inlet)) Plateau as andeast of the well the Manihiki as Manihiki Plateau Plateau, presumedViso which multiple have et possibly smaller been al., subducted fragments 2005).placement, (Larson to et The since al., the secondary break-up 2002; northeast volcanism, of which and Ontong can Java be Nui related took to later place volcanic shortly phases after its em- the first time. 2 Geological background tion data the deep crustal structure of both sub-plateaus is revealed and interpreted for in the western centralheterogeneous Pacific, crustal is character. such a LIP with atypicalof features the such Manihiki as Plateau, arated the laterally by Western the Plateaus Danger and Islandmatic the Troughs. Did history? High both The Plateau, sub-plateaus fragmentation which experience ofdistinct are the the sepa- same phases Manihiki mag- of Plateau poses igneousPlateau the and or question, which tectonic whether role processes theing, Danger led modeling Island to Troughs and played the in interpreting this break-up recently scenario. to By acquired process- the seismic Manihiki refraction/wide-angle reflec- oceans was explained by the(Miura mantle et plumes al., having 2004; ansince White initial this and phase plume McKenzie, head of 1995). model aand But cannot hot this Ernst, explain spot scenario all 2008; trail has characteristicsLarson Co been of and debated, oceanic Erba, LIPs 1999; (Bryan McNutt, 2006; Tarduno, 1998). The Manihiki Plateau, located volcanic stage of a75 % LIP of event its igneous is volumeand characterized (Bryan Richards, and by 2011; Ernst, the 2008; Miura emplacement Bryan etsecondary and of al., volcanism Ferrari, 2004). approximately 2013; and Karlstrom Later show volcanicplacement longer stages rates. can emplacement The be periods crustal summarizedcrustal as structure as layer of well with oceanic as high LIPs smallerand seismic commonly volcanic em- flow consists units of in the a2010; uppermost Wignall, lower crust 2001). (Co In previous publications, the formation of LIPs on continents and 2004). The emplacement ofextinction LIPs events can (Bryan for andLarson instance Ernst, and be 2008; Erba, linked Co 1999;sive to volcanic Tarduno, multiple 1998; eruptions global Wignall, occurringan mass 2001). during anomalously LIPs thick a oceanic are relatively crust the short (Bryan result time and of (1–5 Ernst, Myr) mas- 2008; resulting Wignall, in 2001). This first in plate motion by thickening of oceanic crust (Bryan and Ernst, 2008; Miura et al., 5 5 25 15 20 10 25 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 1.5 Ma Sonne. ± Ar dated 39 ) was used / 3 Ar 40 erent crustal structures ff 3.5 Ma) with an unusual compo- ± 1868 1867 , which is permanently installed on R/V Ar age of 117.9 1.6 Ma (Hoernle et al., 2010). In the Danger Island 39 / ± Ar 40 0.7 Ma) (Ingle et al., 2007). ± erent sub-plateaus and their magmatic and tectonic relationship ff cruise SO-224 in 2012 (Uenzelmann-Neben, 2012), the Alfred We- Kongsberg Simrad EM120 Sonne Ar age of 99.5 39 / Ar An array of 8 G-Guns™ (type 520) with a total volume of 68 L (4160 in This second stage of episodic volcanism on the Manihiki Plateau is also depicted by The upper basement and the sedimentary cover of the Manihiki Plateau has been Hussong et al. (1979) published first estimates on the crustal structure of the Manihiki 40 ensure better ray-coverage at the plateau margins. as a seismic source.10 The m G-Guns™ water-depth and were fired towedDuring at in the nominally four 200 acquisition, clusters bara of multichannel operating 3000 two pressure seismic m guns every long reflection each fullto digital data minute. at the solid was seismic streamer experiments, also multibeam (Sercelcruise recorded bathymetry Sentinel™) with data a with of were 240 collected throughout channels. the In addition consisted of 28 ocean-bottom(OBH) seismometer stations (OBS) spread andequipped out 5 with over ocean-bottom a 500 km hydrophone 3-componentOBH (4.5 long stations s profiles are natural each. period) onlya equipped seismometer The constant and with OBS 14.1 a a km stations hydrophone. hydrophone. on were Station AWI-20120100 spacing and varied 10.9 km between to 24.1 km on AWI-20120200 to 3 Data acquisition, processing, and modeling3.1 parameterization Data acquisition During R/V gener Institute (AWI) collected two deeplines crustal (Fig. seismic refraction/wide-angle 1), reflection crossing thePlateaus two main (AWI-20120100) sub-plateaus and of the the High Manihiki Plateau: Plateau the (AWI-20120200). Western Both seismic lines gravity anomaly maps (Sandwell andof Smith, the 1997) sub-plateaus, plate indicate tectonic di 2012, reconstructions of 2013; Ontong Java Taylor, Nui 2006)disregard (Chandler treat its et al., fragmentation. the Manihiki Plateau as a single tectonic block and to the other parts of the plateau is still poorly understood. Although satellite-derived the evolution of the di ( multiple seamounts on the High1991). Seismic Plateau reflection (Beiersdorf data et image al., severaltary volcaniclastic 1995b; layers column Coulbourn in (Ai the and lower et Hill, sedimen- a al., shallow 2008; or subaerial Schlanger environment et during2008). the al., secondary It 1976; phases is Winterer of important volcanism et (AiPlateau to al., et along al., 1974), note, with pointing that the to most Dangerthe of Manihiki Island Plateau, Troughs the and such publications as the have the Manihiki focused Western Scarp. Plateaus, on Other are the areas poorly High of sampled and therefore below seafloor (Schlanger ettholeiitic al., 1976). basalts This reveal basaltic basement(Timm layer ages and et other of al., the 2011)Troughs, tholeiitic High and basalts Plateau 122.9 ( betweensition 124.6 are present, as well as alkali basalts possibly related to later volcanic stages Manihiki Plateau was 3.1 timessimilar features thicker as than described average for oceanic1979). the crust crust and of that the it Ontong showed Java Plateau (Hussong etstudied al., from samples collected1995a; by Clague, multiple 1976; dredges Hoernle (AiTimm et et et al., al., al., 2010; 2011; 2008; Werner Ingle BeiersdorfDrilling et et et al., Project al., al., 2013) (DSDP) and 2007; Leg short Schlanger 33 sediment et Site cores. al., Drilling 317 at 1976; reached Deep a Sea basaltic layer in a depth of 910 m (Clague, 1976), the Suvorov Throughat and the the eastern Manihiki part Scarp, of a the former plateau shearing (Larson zone etPlateau. al., However, 2002). their experiment, using seismicof sonobuoy the data, lower did crustal not provide layers data or the upper mantle, but it was inferred that the crust of the Troughs, which are a failed rift separating the High Plateau from the Western Plateaus 5 5 20 15 10 25 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | n /S n wave wave P P-Ray (upper- P P umc (upper crust), /S (Zelt, 2004). We uc umc P /S ZP uc wave velocity models P . Reflected phases al- P S wave modeling to ensure wave models and gridded layer S S S wave velocities to rock densi- P (upper crust), wave models. and (lower crust)) on the High Plateau and ected by large-amplitude anomaly ff S lc P uc wave models are named respectively layer /S /S S lc and uc P P P P/S and wave velocity models is generally lower than 1870 1869 P layer for the reflection at the crust-mantle boundary P S S erent crustal layers of the m ff and wave velocity models. Unfortunately, only little to no P (lower crust)) on the Western Plateaus (Figs. 2 and 3), P/S wave model has a sparser resolution than the layer m lc wave model were used for P P (Zelt and Smith, 1992) and its graphical interface S P /S lc P (lower-middle crust), wave velocity distribution was returned from the lower crust and lmc Rayinvr S wave velocity-depth modeling was carried out using the forward /S S lmc P ine, a perfect fit could not be achieved by retaining realistic model param- ffl (middle crust), wave velocity-depth model and converted the mc wave and P Manihiki Plateau /S The Poisson’s ratio can contribute further parameters on the composition of the crust P Refracted and reflected phases in the mc part of the westernmost HighBathymetric Plateau and is also seismic covered at reflection the data eastern end reveal of a this profile. rough seafloor with multiple faults 4.1 Bathymetric and sedimentary features The two seismic refraction/wide-angle reflectionmain profiles allow plateaus a of comparison ofPlateaus the the from two Manihiki the Plateau. northwest4800 m Profile to in AWI-20120100 the the crosses southeast Tokelauof Basin (Fig. the the to 1). profile Western 3800 are The m the water on Danger depth Island the Troughs Western ranges with Plateaus. a from maximum The depth deepest of areas 4900 m. A small eters. In several iterations, thethe model observed parameters the were gravity altered anomalies to and generate the a best fit to 4 The crustal structure of the Western Plateaus and the High Plateau of the As shipborne gravityrecords data extracted were from not theand collected, Smith global we (1997) satellite-derived relied with gravity valuesusing on anomaly extracted the free-air along forward grid our gravity modeling by seismic softwarethe anomaly profiles. Sandwell IGMAS, In we a incorporated starting theties model layer using boundaries the of relationshipvelocity by clusters Hamilton representing (1978). the We di (Table assigned 1). rock As densities this to 2-Dfeatures approach o turned out to be a their distribution. Since the model, it limits the resolution of the Poisson’s ratio3.3 model. Modeling of gravity data the Poisson’s ratio for every velocity node of the distribution of predominantly mafic and felsic rocks can be constrained. We calculated P and four distinct groupsmiddle of crust), crustal phases(Figs. ( 4 and 5).the The resolution resolution of of the the information presented on the the mantle. (Christensen, 1996). For example, alteration processes such as serpentinization or the to their corresponding layer ways represent the reflection atfor the the base refracted of phase the(Moho). and layer. Mantle We phases observed are three called distinct groups of crustal phases ( into account. modeling software (Fromm, 2012). We usedthe bathymetric cruise, and in order seismic to reflection constrainof modeling records the parameters sedimentary obtained for the cover. during The seafloornodes and layer established the boundaries thickness by and model the comparable coordinates models of and allow the the velocity calculation of the Poisson’s ratio. The OBS/OBH field dataformat. were After merged relocalization with of navigationfracted the and data OBS reflected and positions arrival converted phases usingassigned to were the picked picking SEGY- direct-wave with uncertainties arrivals, the all software to re- the individual picks taking the signal-to-noise-ratio 3.2 Processing and modeling of seismic refraction/wide-angle reflection data 5 5 20 25 10 15 25 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | . 1 1 − − from (Fig. 6). umc 1 − /S in the west 1 umc − wave velocities wave velocities P S S wave velocities between ). It is important to note 1 (Fig. 8). − P are common. This block is 1 in the Penrhyn Basin (Fig. 9). 1 − − 1 − wave velocity model shows more wave velocities show a block-like at st22 (Fig. 7). S wave velocities decrease down to S wave velocities (e.g. at st21) in the 1 − P P ). The Danger Island Troughs area lacks ) (Figs. 2–5). On the Western Plateaus, 1 − mc wave velocities between 2.7 and 3.2 km s /S 1872 1871 wave velocities range from 2.9 to 3.2 km s wave velocities, which corresponds to higher between st8 and st12. From 180 km to 250 km S mc 1 S S P − are present. from lower-middle crust) on the High Plateau and 1 − wave velocities between 5.2 and 5.5 km s lmc P towards the Danger Island Troughs. /S 1 − lmc P at the base of the layer (Figs. 2–5). in the Samoan Basin to 2.9 km s P 1 uc (Fig. 6). In between the ridge-like structures at 230 and 270 km − (Figs. 4 and 8) and wave velocities from 2.9 to 3.3 km s P 1 1 S − ) and constrained by the wide-angle reflections at the upper layer − wave velocities of up to 4.3 km s wave velocities between 5.2 and 5.8 km s uc and S P P /S s with small patches of lower velocities (3.8 km s uc P 1 P − wave velocity structure of the middle crust is homogeneous and ranges between P wave velocity model. The upper crust of the surrounding ocean basins, the Penrhyn Basin and the Samoan The High Plateau shows higher and more homogenous On the Western Plateaus, the upper crust is characterized by a rough basement to- Profile AWI-20120200 images the High Plateau of the Manihiki Plateau in a west to upper-middle crust and one layer on thethe Western Plateaus ( 5.8 and 6.8 km s profile distance, the middle crustalpresent in layer the extends gravity to anomaly the modelvariation basement. (Fig. in This 11). The feature the is middleto also crust, very high with valuesdecrease to ranging 3.8 from to 4.0 3.6 km s to 4.0 km s crust (Christensen, 1996). 4.3 Middle crustal layers The middle crustal layers of the Manihiki Plateau consist of two layers ( in the seismic reflection datacenters (Pietsch can and Uenzelmann-Neben, be 2014). connectedP Those volcanic to areas of higher Basin show range from 3.3 km s Whereas the Samoan Basin shows Poisson’srelated ratio to values of basalt around (Christensen, 0.25, 1996), whichPoisson’s the ratio can Penrhyn values be Basin of on over the 0.30 other (Fig. hand 10). shows Those high values are typical for serpentinized velocities in the middle crusta (3.7 visible to upper 4.3 km crust s (Figs. 2b and 6). 4.7 and 5.6 km s (Figs. 5 and 9). Several magmatic extrusive and intrusive features can be identified followed by an area of unusual high Between 50 km and4.5 km s 300 km profilethat distance, due to theis malfunction not of ideal two inities this neighboring area. ranging stations Between (st19, from 300 st20) 3.0structure and the to 370 (Fig. km ray 4.3 7). profile km coverage s From distance,Velocities unusual 0 decrease low to to 2.5 veloc- 100 to km, profile 2.8 km distance, s acoustic basement of the seismicphases reflection ( data and areboundary represented by the refracted pography and a widely variableof velocity an field. upper The crustal western layer 50 km with of the profile consist the west form sharpan flanks approximately bordering 800 m the thickcentral sub-plateau. sedimentary plateau. Seismic cover Sedimentation reflection and appears databetween several to basement reveal basement highs be highs on restricted the on margins to the of pockets the and High4.2 Plateau. small basins Upper crustal layers The upper crustal layer of the Western Plateaus and the High Plateau include the numerous basement highs. east section (Fig. 1).Penrhyn The Basin water to a depth mean rangesseafloor. depth from The of 5100 Manihiki the m Scarp High in in Plateau the of the Samoan 2500 east m and Basin with the and a margin relatively towards smooth the Samoan Basin in and graben systems. Sedimentary cover is mainly restricted to the basins between the 5 5 25 20 10 15 25 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ) n 1 − ffi wave wave S P wave ve- and at the P . The crustal 1 1 − − wave velocities wave velocities of S n et al., 2006; Ri- ffi P on the High Plateau 1 − . The 1 − n and Eldholm, 1994; Co erent sub-plateaus as well as ffi ff wave velocities between 3.0 and (Figs. 8 and 9). The lower-middle wave velocities (6.7 to 6.9 km s ) as well as reflections at the Moho 1 n S − P P wave velocities range between 6.8 and on the Western Plateaus (Fig. 7). At the P 1 ). wave velocity and gravity models along with − lc wave velocities reach 4.4 km s 1874 1873 S /S S lc (Fig. 6) and P are present (Fig. 9). and 1 1 − P − waves is poor on the High Plateau and only very little wave velocities of 8.1 km s S P er. Whereas the High Plateau shows a constant crustal thick- ff ), a so called high-velocity zone (HVZ) (Co 1 − are present. The Poisson’s ratio shows three distinct areas of higher 1 − 7.1 km s erent magmatic and tectonic regimes on the Manihiki Plateau wave velocities and therefore the volcanic structures within the upper crust. are also common at other oceanic LIPs (Co on the Western Plateaus (Fig. 6) and 7.0 to 7.8 km s (Fig. 7). This crustal layer is thicker in the western part of the High Plateau. > ff ) (Figs. 2 and 4). On the High Plateau, the Moho is visible in the data through- 0.26) below the central plateau (Fig. 10). Those can be connected to areas P 1 1 1 P − − − > m wave velocities between 4.0 and 4.3 km s P S The middle crust is present at the Danger Island Troughs. East of the troughs, the 2011; Uenzelmann-Neben et al.,oceanic basins, 1999) the with Western steep Plateaus boundaries shows towards a gradual the decrease adjacent in the crustal thick- sub-plateaus exhibit a HVZ in7.1 km the s lower crust. Theseet HVZs al., 2006; with Richards velocities et higher al.,presence than 2013; of Ridley gabbros and and Richards, 2010) theand and olivine Richards, can 2010) and be (Figs. pyroxene related 13 fraction to and ofand 14). the The primary the crustal magmas High thicknesses (Ridley Plateau of the di ness Western of Plateaus 20 km, which isand comparable southern to other Mozambique oceanic LIPs Ridge such (Gohl as the and Agulhas Plateau Uenzelmann-Neben, 2001; Gohl et al., works, the Western PlateausPlateau was (Hussong assumed et to al.,crustal layers. be 1979; By of Viso interpreting our a etthe similar al., Poisson’s ratio structure 2005) model, due as thetheir crustal to the individual structure the High margins of lack the and di of adjacent data ocean from basins deep can be further constrained. Both the mantle below the Westernthickness Plateaus of are slightly the higher Western17.2 with km 8.2 Plateaus east km s of ranges the between Danger Island 9.3 km Troughs (Figs. in 6 and the 11). Samoan5 Basin to Two di In general, the crust ofOntong the Java Manihiki Nui Plateau “Super-LIP” is (Chandler severely et faulted al., due 2012, to 2013; the break-up Taylor, 2006). of In previous out the central plateauSamoan at a Basin depth and of thementary 20 Penrhyn km cover, Basin changes below rather the the abruptly crustal seafloor toboundary thickness, only (Figs. are 5 which 8 km. also includes Those and consistent depths the 12). withmantle for sedi- In the gravity shows crust-mantle the anomaly normal modeling mantle (Fig. 12). The uppermost itself ( The boundary between the crystallineby crust refracted and phases the from mantle the (Moho) uppermost can mantle be ( constrained 7.8 km s (Fig. 8). The ray-coverage of interpretable signals were returned for thevelocities lower range crust between of 4.1 the Westernwestern and Plateaus. 4.3 margin km s ofManihiki the Scarp High values of Plateau, 4.7 km s 4.5 Crust-mantle boundary and mantle The lower crust ofvelocities most ( Large Igneous Provincesdley consists and of Richards, asub-plateaus 2010). zone within of On the high lower the crust ( Manihiki Plateau, we observe this HVZ on both and crustal layer crops outup at to the 4.65 km seafloor s atvalues ( the Manihiki Scarp.of Here, higher Middle crustal layers are not present in the adjacent4.4 oceanic basins. Lower crustal layers middle crust isthe divided into lower-middle two crustlocities separate (Figs. between crustal 4 5.4 layers, and and the3.6 km 6). 6.4 s upper-middle km s The crust upper-middle and The crust lower-middle crust shows presents relatively high 5 5 25 15 20 10 25 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | n et al., wave ve- ffi S wave modeling and S P and P ers significantly. The High Plateau con- ff 1876 1875 erent velocity field and a small decrease in den- ff The Danger Island Troughs dissect the Manihiki Plateau into the two main sub- Whereas the High Plateau shows clear indications for multiple volcanic phases within The upper crust of the two sub-plateaus di The middle crust of both sub-plateaus shows similarities in the plateaus. The trough is characterized(Fig. by 13). the The absence lower crustal ofrelicts layers typical of as upper well a crustal as material former theIsland crust-mantle spreading Troughs mark boundary center show the at onlythe distinct few this Western change position. Plateaus over and In betweenPlateau the a the (Figs. upper-middle single middle 2b crust layer crust, and middle andregimes, the 13). crust lower-middle the Thus, Danger tectonically crust on deformed the of Western DangerPlateau. the Plateaus Island and High Troughs the separates volcanically altered two High structural ified the plateau’s structureseamounts, can enormously. only Volcanic be extrusions,Western interpreted e.g. Plateaus for the (Fig. the occurrence 13), Tokelautures Basin at of of and the least are Western in not Plateaus thestructures. are present formed currently on by imaged sedimentary the basins area. and The horst dominant and graben fea- tured by fault systems and horstas and well graben as features (Fig. gravity 13). anomalybe modeling debated reveal whether the the presencesive upper carbonate of banks crust diverse (Grevemeyer et rock consists al., types.High of 2001). It Plateau volcaniclastic Volcanic can structures are deposits comparable not or toThe the visible even majority in mas- of any the usedprocesses. faults data are Another set normal indicator on faults, for thedepth which crustal towards is southern the extension consistent Western Tokelau Basin. with is Plateaus. Therefore, crustal tectonic the stretching deformation constant seems decrease to have in mod- Moho selves show basaltic flow unitsin and have this no area. indications for large-scale serpentinization its upper crust, the data fromonly the Western in Plateaus the presents possible Samoan basaltic flow Basin. units The upper crust of the Western Plateaus is heavily struc- Penrhyn Basin. The margins towards the Samoan Basin and the Samoan basin them- the Possion’s ratio (Fig. 10) and lower densities (Fig. 12) at the Manihiki Scarp and the clastic and pelagic sedimentarythe rocks upper (Ai crust et consists al., of 2008;2000; basaltic Beiersdorf Karlstrom flow et units and al., as Richards, well 1995b).the 2011), as Thus, multiple possibly mafic stages intrusions interlayering of (Ito each secondarythe and volcanism. other Taira, margins Massive as fault of a systems result areAt the only of High the present at Plateau Manihikimiddle (Fig. Scarp, crust, 14) deeper crop (Pietsch crustal outfaults. and layers, at Based Uenzelmann-Neben, most the on 2014). likely seafloor gravityserpentinized in consistent data in multiple with Viso this ridges et area. the separated We al. lower- by can (2005) deep further postulated reaching support that this the assumption upper by crust high was values in LIP crustal magma transport, which indicatesing the sills formation of during individual later upwardon migrat- stages the of Western volcanic Plateaus. activity. Similar structures cannot besists observed of countless volcanic centers, which are partly eroded and covered by volcani- 2006; Richards etupper-middle al., crust 2013; shows a Ridley slightlysity and di (Table 1). Richards, This transitional 2010). layer isthe On not middle present crust the in underlying the High the Western centralPoisson’s Plateaus. Plateau, ratio, High Additionally, which Plateau the are exhibits three correlated large toreflection areas former of volcanic data higher centers (Fig. observed in 10).the the Those seafloor seismic of “chimneys” the mark High Plateau, formerand possibly during magmatic Uenzelmann-Neben, a 2014). pathways later Karlstrom towards volcanic stage and (Fig. Richards 14) (Pietsch (2011) published a model of oceanic crust in the Tokelau Basin and the oceanic LIPlocity cannot structure. be The identified. middleis crust comparable of to the the lower-middledistribution Western crust can Plateaus of be has the associated a High with velocity Plateau. mafic This field, velocity intrusions which and (Christensen, density 1996; Co ness from 17.2 km in the east to 9 km in the west. A clear boundary between normal 5 5 25 20 10 15 25 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | wave P erent crustal ff n et al., 2006; Ridley and ffi ). 1 − (Fig. 15) (Co 1 − 1878 1877 . This layer is not resolved as a crustal unit in 1 − wave velocities between 6.3 and 7.0 km s P sub-plateaus wave velocities around 6.0 km s erent magmatic and tectonic evolution after their emplacement as part of Ontong ff environments of the Manihiki Plateau erences, especially in the upper crustal layers and the crustal thicknesses. P The High Plateau shows local volcanic centers, which have been the outlets of intru- A dominant feature of all oceanic LIPs is the HVZ of the lower crust with The High Plateau along with other oceanic LIPs has an upper middle crustal layer wave velocities in the lower crust. High velocities are also present in the lower middle ff ume of the igneoustherefore province it (Bryan is and consistent Ernst, that 2008; the Karlstrom lower and crustal Richards, layers 2011), as well as the middle crustal lay- (Fig. 15). The HighLIPs. The Plateau two does main show sub-plateausa all of di the features Manihiki previously PlateauJava described hence Nui. must for have oceanic undergone 6.2 Emplacement scenario of the Manihiki Plateau and its two major The initial volcanic event of a LIP emplaces approximately 75 % of the total igneous vol- attributed to fault complexesreported and for any ridge oceanic systemspresent LIP. Basaltic in (Fig. the flow 11). Tokelau units Basin. Thisdo cropping Therefore, the has not out Western have at so Plateaus the the of farmafic typical seafloor the intrusions not crustal Manihiki are in been Plateau structure only the upper-middle of crust an and oceanic basaltic flow LIP units and within lack the features upper crust such as on the Ontong JavaWood, Plateau 1994; (Inoue Davy et et al., al.,activity 2008; 2008) is Hoernle or also et the visible al.,and in Hikurangi Uenzelmann-Neben, 2004). 2014). Plateau seismic Extrusive Buried reflection (Davy and seamount and chains data intrusiveanomaly can volcanic throughout grids also the be on located High the into Plateau High gravity be (Pietsch Plateau the of case for theangle the reflection Manihiki southern data Plateau nor Western the (Fig. Plateaus. multichannelern Neither 12). seismic the reflection This Plateaus seismic data seems indicate acquired refraction/wide- on not extensive the West- secondary volcanism. Gravity anomalies are mainly with igneous rocks (Grevemeyer etconsists al., of 2001). basaltic The flow upperlayers units crust formed of interlayered by oceanic with regional LIPs secondary pillow mainly volcanic lavas phases and (Inoue possibly et sedimentary al.,sive 2008). and extrusive magmatism during secondary volcanic phases, similar as observed that are associated with volcaniclastic sedimentation and carbonate banks rather than Karlstrom and Richards, 2011;Western Miura Plateaus consists et of al., several areas 2004). of In very low addition, velocities and the low upper rock densities crust of the P crust ( of all LIPs, but in generalsitional is layer is present not as presentPlateaus a on is part missing the of a Western the crustal Plateauswith middle layer (Fig. present mafic crust. 15). in Surprisingly, intrusions Therefore all this other the formed tran- oceanic Western during LIPs, a a layer secondary associated volcanic phase (Inoue et al., 2008; distribution is also similar2004), to but the that Ontong of Java Plateau the exhibits southern up to Ontong twicevelocities Java the ranging Plateau crustal between thickness. (Miura 7.7 and etRichards, 7.1 al., km 2010). s Both the Western Plateaus and the High Plateau show such high di 6.1 Comparison with other oceanic LIPs By comparing the Western Plateauscrustal and thickness the and High velocity-depth Plateau distribution with ofthe other the Kerguelen High oceanic Plateau Plateau LIPs, resembles the (Charvis those1967), and of Agulhas Operto, Plateau 1999), (Gohl Brokenand and Ridge Mozambique Uenzelmann-Neben, (Francis Ridge and 2001; (Gohl Raitt, Parsiegla et et al., al., 2011) 2008) (Fig. 15). The proportional velocity-depth This paper presents thesub-plateaus of first the Manihiki comprehensive Plateau. The insightThe results Western into of our Plateaus the analyses and revise crustal earlier the models. structure High of Plateaus the of the Manihiki Plateau show amazing 6 Discussion: Western Plateaus vs. High Plateau – two di 5 5 25 20 10 15 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ective, and volcanic ff erent stages of the evolution of ff 1880 1879 During a later stage of secondary volcanism, the volcanic activity on the High Plateau At the Western Plateaus, we could not identify any evidence for secondary volcan- With the beginning of seafloor spreading in the Ellice Basin and separation of the Simultaneously, a secondary volcanic stage started resulting in seamount chain vol- Rifting of Ontong Java Nui followed this initial magmatic phase (Chandler et al., 2012, partially deposited on the High Plateau, but also becomes reworked and integrated into subsided deeper and wasmentation. farther Therefore, away the from western the Westernand source Plateaus mafic rocks experienced region are less of exposed sedimentation, volcaniclastic in sedi- the upper crust. has weakened and moved itsare activity center better to preserved, the east,reflection and as data eastern early (Ai volcanic et deformed structures al.,volcanic 2008; sedimentary edifices Pietsch layers and are Uenzelmann-Neben, are eroded, 2014)seismic visible (Fig. reflection leading data 16). in to (Pietsch Older and seismic an Uenzelmann-Neben, 2014). almost The smooth eroded material acoustic is basement in the is also likely sinceface. the It is Manihiki also Plateau common, stillprocesses that and has carbonate are platforms been later form relatively on oncrust, close fault buried consisting blocks by to created of sedimentation the by sedimentary (Bosence, rifting seacome 2005). rocks, sur- Since thins present the towards again, upper the it west, is and likely volcanic that rocks be- this portion of the Western Plateaus had already created during a secondto volcanic the stage sea surface. could Inpathways have this should been case, be eroded erosion visible should as inthe have the they unusual been middle were very low crustal close e layers velocitiesexperienced of of volcaniclastic the the presented and acoustic models. carbonaticples Also, basement sedimentation from infer this (Fig. that area 13).parameters. the are As The Western available no source for Plateaus of rock ground-truthing,the we the sam- High rely volcaniclastic Plateau. only Carbonatic sedimentation on sedimentation, is the e.g. located the geophysical most build-up likely of on carbonate platforms, Timm et al., 2011). InAtoll addition, and volcanic Rakahanga islands (Beiersdorf onthe et Danger the Island al., High Troughs, Plateau 1995a) alkaline such lavas formed are as during emplaced Manihiki this (Ingle et volcanicism al., stage. such 2007). At as basaltic flow units or former seamounts. Of course, upper crustal layers mainly of tholeiitic composition (Clague, 1976; Hoernle et al., 2010; Ingle et al., 2007; formed the upper crust of the Manihiki Plateau by intrusive and extrusive volcanism Manihiki Plateau from theWorthington Ontong et al., Java 2006), Plateau the Western (ChandlerAs Plateaus et faults experienced less from al., tectonic the deformation. 2012;stretching deeper Taylor, forces 2006; crust have been to present thethe throughout Western seafloor the Plateaus. can di be detected (Fig. 13), thecanism crustal on the Highmagmatic Plateau pathways within (Fig. the 16). crust The are relicts visible in of our volcanic data. centers The as secondary well volcanism as the On the eastern marginform of fault the creates the Manihiki Manihiki Plateauthe Scarp a (Fig. south, 1) massive the (Larson north-south Hikurangi etby trending al., Plateau the 2002; trans- rifted development Viso from of et the al., the2000; 2005). Osbourn High Davy To Trough et Plateau ocean al., of spreading 2008; center the Worthington (Billen Manihiki et and al., Plateau Stock, 2006). 2013; Hoernle et al.,2006) 2004, (Fig. 2010; 16). Taylor, The 2006; Danger TimmPlateaus, Island formed et Troughs, during which al., separate this 2011; the timeeral (Ingle Worthington High fault et and et systems al., the al., at 2007; Western the TimmJava et Western Plateau al., Plateaus 2011) and initiating along the the withmargin break-up sev- Manihiki at between Plateau the the Ontong eastern at(Gladczenko Ontong several et Java locations al., Plateau (Fig. 1997; showsassociated 13). Klosko indications with et The the for al., crustal a conjugate stretching 2001; thinned during Richardson the LIP initial et crust phase al., of 2000), Ontong Java which Nui can rifting. be crust and the lowering middle Ontong crust Java were Nui“Super-LIP” emplaced (Chandler was during et presumably the al., at “Super-LIP”crustal 2012, subaerial layers event 2013; and level creat- Taylor, volcanic 2006). (Fig. centers A 16). were likely large Therefore subject part the to former of erosion. upper this ers show similar attributes on both sub-plateaus of the Manihiki Plateau. The lower 5 5 25 20 10 15 25 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | erent sub- ff erent magmatic ff erent tectonic and ff from the magma supply initiating ff 1882 1881 erent on each sub-plateau, which indicates possible separation – spatially and ff The High Plateau shows the standard crustal structure of anThe oceanic Danger LIP Island with Troughs is the distinct border betweenOur the models volcanically indicate active that the Manihiki Plateau experienced a di The Western Plateaus have a crustal thickness between 9.3 km in highly stretched The interplay between tectonic and magmatic overprint proves to be a crucial key After the last magmatic pulse ceased, further pelagic sedimentation covered the vol- In summary, the Manihiki Plateau experienced multiple stages of magmatic emplace- ern Plateaus experienced crustalsights stretching in the and formation magmatic and starvation. evolution of These the new Manihiki Plateau in- infer that the di middle and lower crust. High Plateau and the Westernalteration, Plateaus, at which least did in not their experience southern any parts. further volcanic magmatic evolution after thethe emplacement High as Plateau aPlateau underwent and part secondary the Hikurangi of volcanism, Plateau, Ontong and comparable limited Java tectonic to Nui. forces the at Whereas its Ontong margins, the Java West- other oceanic LIPs, it becomessecondary obvious volcanic stages. that the Western Plateaus did not experience a crustal thickness of upondary to volcanic 20 km. stage In the are upper visible. crust The former eruptive feeder centers system of a of sec- the LIP is traceable in the We present the firstsub-plateaus seismic – the refraction/wide-angle Western reflection PlateausFrom models and this of the newly High the gained Plateautectonic two information and – main magmatic of on evolution the the of Manihiki this crustal Plateau. oceanic structure LIP can of beLIP the reconstructed. crust sub-plateaus, in the mafic the extrusives west as and expectedcompacted 17.2 km for sediments in an in basins the oceanic created east. LIP. by The The deep upper upper reaching crust faults. crust consists By does comparison of not with highly consist of aspect in understanding therifting crustal of nature the “Super-LIP” of Ontong the Java Manihiki Nui. Plateau and its role7 in the Conclusions Mahoney and Spencer, 1991; Mahoneythe et prominent al., dissection 1993). between The those Dangerand two Island tectonic sub-plateaus evolution. Troughs and form Our their data di terial indicate crops the out lack at of the upper basehave crust, channelized of and and the lower highly limited sedimented crustal the trough.High ma- magma Deep supply Plateau. reaching to The faults the could source Dangeris Island of di Troughs the and the secondarypetrologically volcanism – on of the the rifted source. Ontong Java Nui ment and tectonic deformation. Thetonic Western Plateaus forces was related mainly a toof subject the the to LIP’s the break-up crust. tec- of Thethe Ontong Western secondary Plateaus Java volcanic was Nui cut stages,the and o conjugate which the Ontong are Java resulting Plateau present stretching and Hikurangi on Plateau the (Hoernle et High al., Plateau, 2004, 2010; but also on High Plateau. Onbasement, the which Western leads to Plateaus, the faultslate conclusion secondary that can crustal volcanism be stretching along was with observed still further present up sedimentation. during to thecanic relicts acoustic and tectonic motion generatedsided faults and into ridges. the The current Manihiki Plateau water-depthfor sub- of the Western 2600 m Plateaus for (Fig. the 16). High Plateau and 4000 to 3600 m basalts with a U-shapedof incompatible several element elements are pattern formed. andsampled Those unusually Manihiki basalts low Plateau cannot abundance be orpropose found the anywhere a else other magma on partswedge formation the of material characterized Ontong and by Java mixed extensive Nui. with melting Ingle volcaniclastic of et sediment, depleted al. possibly mantle (2007) originated from the the magma surfacing at the Danger Island Troughs (Ingle et al., 2007). Here, tholeiitic 5 5 25 15 20 10 25 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , , 2012. 10.1130/0091- 10.1016/0025- for their support 10.1016/S0264- , 1994. Sonne , 1991. 10.1016/j.sedgeo.2004.12.030 10.1016/j.epsl.2012.03.017 , 2008. 10.1029/93RG02508 , 1994. , 2000. , 2008. , 1995b. , 1993. 1884 1883 , 1999. , 2002. , 2006. 10.1016/0025-3227(91)90111-G , 1996. 10.1029/2000JB900035 10.1016/j.earscirev.2007.08.008 , 2013. , 2013. We thank Ernst Flüh and Jörg Bialas of GEOMAR for providing the OBS 10.1016/0025-3227(94)90117-1 , 1995a. , 1999. 10.1007/s11001-008-9042-0 10.1016/0025-3227(95)00021-P 10.1016/S0012-821X(98)00282-9 10.5670/oceanog.2006.13 10.1093/petrology/43.7.1121 10.1029/95JB03446 10.1130/B30820.1 10.1093/gji/ggt075 n, M. F., Duncan, R. A., Eldholm, O., Fitton, J. G., Frey, F. A., Larsen, H. C., Ma- n, M. F. and Eldholm,n, O.: M. F., Pringle, M. Scratching S., Duncan, R. the A., Gladczenko, T. P., Storey, surface: M., Müller, R. estimating D., and dimen- n, M. F. and Eldholm, O.: Large igneous provinces: crustal structure, dimensions, and ffi ffi ffi ffi 118, 139–151, doi: Mar. Geol., 98, 367–388, doi: between flood basaltsdoi: and continental breakup, Earth Planet. Sc. Lett., 166, 177–195, honey, J. J.,and Saunders, scientific A. ocean D.,doi: drilling: Schlich, status R., quo and and Wallace, a P. look J.: ahead, Large Oceanography, igneous 19, provinces 150–160, sions of large igneous provinces, Geology,Gahagan, L. M.: Kerguelen 21, hotspotdoi: magma output since 515–518, 130 Ma, J. Petrol., 43, doi: 1121–1137, 3707(98)00029-5 doi: Troughs, Manihiki Plateau, Initial Rep. Deep Sea, 33, 891–911, 1976. 7613(1993)021<0515:STSEDO>2.3.CO;2 external consequences, Rev. Geophys., 32, 1–36, doi: progress in our understanding overdoi: the last 25 years, Geol. Soc. Am. Bull., 125, 1053–1078, latitudes: evidence fordoi: large-scale rotation since 123 Ma?, Geophys.Indian J. Ocean) Int., from 194, wide-angle 18–29, seismic data, J. Geodyn., 28, 51–71, doi: 2005. Rev., 86, 175–202, doi: Ontong Java Nui: implicationswander, for Earth Pacific Planet. absolute Sc. plate Lett., motion, 331–332, hotspot 140–151, doi: drift and true polar 29–59, doi: 105, 13481–13489, doi: settings in the Cenozoic, Sediment. Geol., 175, 49–72, doi: region, Manihiki Plateau, Western29, 13–26, Pacific, doi: from seismic stratigraphy, Mar. Geophys. Res., Won, M. Z.: High-resolution stratigraphy andmental the changes response in of the biota central to Late equatorial Cenozoic Pacific environ- Ocean (Manihiki Plateau), Mar. Geol., 125, production of EM-typethe ocean early island basalts history3227(94)00107-V and of large the volumes Manihiki of Plateau, volcaniclastites during Mar. Geol., 122, 181–205, doi: Ontong Java Nui. plateaus of the Manihiki Plateau played a key role in the break-up of the “Super-LIP” Davy, B. and Wood, R.: Gravity and magnetic modelling of the Hikurangi Plateau, Mar. Geol., Coulbourn, W. T., and Hill, P. J.: ACourtillot, field of V., volcanoes Jaupart, on the C., Manihiki Manighetti, Plateau: mud I., or Tapponnier, lava?, P., and Besse, J.: On causal links Co Co Co Clague, D. A.: Petrology of basaltic and gabbroic rocks dredged from the Danger Island Christensen, N. I.: Poisson’s ratio and crustal seismology, J. Geophys. Res., 101, 3139–3156, Co Bryan, S. E. and Ferrari, L.: Large igneous provinces and silicic large igneous provinces: Charvis, P. and Operto, S.: Structure of the Cretaceous Kerguelen Volcanic Province (southern Chandler, M. T., Wessel, P., and Sager, W. W.: Analysis of Ontong Java Plateau palaeo- Bryan, S. E. and Ernst, R. E.: Revised definition of large igneous provinces (LIPs), Earth-Sci. Chandler, M. T., Wessel, P., Taylor, B., Seton, M., Kim, S.-S., and Hyeong, K.: Reconstructing Billen, M. I. and Stock, J.: Morphology and origin of the Osbourn Trough, J. Geophys. Res., Bosence, D.: A genetic classification of carbonate platforms based on their basinal and tectonic Ai, H.-A., Stock, J. M., Clayton, R., and Luyendyk, B.: Vertical tectonics of the High Plateau References Beiersdorf, H., Bach, W., Duncan, R. A., Erzinger, J., and Weiss, W.: NewBeiersdorf, evidence H., for Bickert, the T., Cepek, P., Fenner, J., Petersen, N., Schönfeld, J., Weiss, W., and German Federal Ministry of Educationand and by Research (BMBF) institutional under resources project of number the 03G0224A AWI. and OBH systems. Weand also assistance thank during Cpt. L. thethe Mallon cruise AWI and So-224. Research his This crew Programm project of PACES. contributes This R/V to project the has Workpackage been 3.2 of funded through a grant by the Acknowledgements. 5 5 30 25 20 15 10 30 25 20 10 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , , 2007. 10.1130/0091- 10.1016/0012- 10.1046/j.1365- http://aforge.awi. , 2000. , 1967. 10.2113/gssajg.114.3-4.379 , 2004. n?, Science, 313, 1394, , available at: ffi 10.1130/G23741A.1 , 2001. 10.1029/2000JB900036 , 2008. , 1999. , 2001. aforge.awi.de 10.1029/JZ072i012p03015 , 1978. , 2005. n, M. F., Kimura, J.-I., Hirano, N., and Nakan- , 2002. 1886 1885 ffi Home, > PRay , 1979. , 2010. > , 2006. , 2008. , 2004. 10.1016/S0012-821X(03)00629-0 10.1121/1.381747 , 2011. 10.1029/1999PA900040 , 1997. 10.1029/2007GC001780 Projects n, M. F., and Eldholm, O.: Crustal structure of the Ontong Java Plateau: , 2001. > ffi 10.1016/j.epsl.2005.03.011 10.1046/j.0956-540x.2001.01521.x (last access: 22 January 2014), 2012. , 1991. n, M. F.: Impact origin for the greater Ontong Java Plateau?, Earth Planet. , F., Reinhard, W., and Mortimer, N.: New insights into the origin and , F., van den Bogaard, P., Reinhard, W., Mortimer, N., Geldmacher, J., ffi ff ff 10.1016/S0012-821X(01)00235-7 n, M. F., Nakamura, Y., Mochizuki, K., and Kroenke, L. W.: Intrabasement reflec- ffi 10.1126/science.1131298 10.1029/2004EO410001 10.1016/j.gca.2010.09.030 10.1029/JB084iB11p06003 10.1029/2010JB008159 10.1029/97JB01636 10.1029/2007GC001855 doi: cal structure and implications of collision between the Ontong Java Plateau and Solomon geochronology of Leg 130Proceedings basement of the lavas: Ocean nature Drilling and Programm origin Scientific Results, of 130, the 3–22, Ontong 1993. Java Plateau, igneous events and the biological,raphy, 14, sedimentary, 663–678, and doi: geochemical responses, Paleoceanog- Stock, J.triple M., junction and in7613(2002)030<0067:MCTEOT>2.0.CO;2 the Clayton, southwestern R.: Pacific Basin, Mid-Cretaceous Geology, 30,Ontong tectonic Java 67–70, evolution oceanic doi: 821X(91)90204-U plateaus, of Earth the Planet. Sc. Tongareva Lett., 104, 196–210, doi: evolution of thedoi: Hikurangi oceanic plateau, EosGarbe-Schönberg, T. D., Am.the and Geophys. Hikurangi Davy, Un.,doi: and B.: 85, Manihiki Age 401–408, oceanic and Plateaus, geochemistrythe Geochim. of Ontong Cosmochim. volcanicdoi: Java Ac., rocks and 74, Manihiki from 1–24, oceanicSc. plateaus, Lett., 218, J. 123–134, doi: Geophys. Res., 84, 6003–6010, tions of the OntongGeosy., Java 9, Plateau: Q04014, implications doi: for plateau construction, Geochem. Geophy. 234, 385–399, doi: ishi, M.: Depleted mantle wedgehiki and Plateau, sediment central Pacific fingerprint Ocean, in Geology, unusual 35, basalts 595, from doi: the Mani- strong chemical mantle root beneath347–361, the doi: Ontong–Java Plateau, Earth Planet. Sc. Lett., 186, 2011. structure and lithospheric flexure147, 123–140, along doi: the Society Island hotspot chain,Soc. Geophys. Am., J. 63, Int., 366–377, doi: loading, J. Geophys. Res., 105, 11171–11183, doi: bers anddoi: timescales for flood basalt eruptions, J. Geophys. Res., 116, B08216, large igneous province, S. Afr. J. Geol., 114, 379–386, doi: Ocean, J. Geophys. Res., 72, 3015–3041, doi: modeling of new gravitydoi: and existing seismic data, J. Geophys.Ocean: Res., evidence 102, from seismic 22711–22729, profiling,246X.2001.01368.x Geophys. J. Int., 144, 632–646, doi: mation, anddoi: Gondwana subduction history, Geochem. Geophy. Geosy., 9,de/gf/project/pray Q07004, Miura, S., Suyehiro, K., Shinohara, M., Takahashi, N., Araki, E., and Taira, A.: Seismologi- McNutt, M. K.: Another nail in the plume co Mahoney, J. J., Storey, M., Duncan, R. A., Spencer, K. J., and Pringle, M.: Geochemistry and Mahoney, J. J. and Spencer, K. J.: Isotopic evidence for the origin of the Manihiki and Larson, R. L. and Erba, E.: Onset of the Mid-Cretaceous greenhouse in theLarson, Barremian-Aptian: R. L., Pockalny, R. A., Viso, R. F., Erba, E., Abrams, L. J., Luyendyk, B., Ingle, S. P. and Co Hussong, D. M., Wipperman, L. K., and Kroenke, L. W.: The crustal structure of Korenaga, J.: Why did not the Ontong Java Plateau form subaerially?, Earth Planet. Sc. Lett., Hoernle, K., Hau Hoernle, K., Hau Inoue, H., Co Ingle, S. P., Mahoney, J. J., Sato, H., Co Klosko, E. R., Russo, R. M., Okal, E. A., and Richardson, W. P.: Evidence for a rheologically Grevemeyer, I., Weigel, W., Schüssler, S., and Avedik, F.: Crustal and upper mantle seismic Ito, G. and Taira, A.: Compensation of the Ontong Java Plateau by surface and subsurface Hamilton, E. L.: Sound velocity–density relations in sea-floor sediments and rocks, J. Acoust. Karlstrom, L. and Richards, M. A.: On the evolution of large ultramafic magma cham- Gohl, K., Uenzelmann-Neben, G., and Grobys, N.: Groth and dispersal of a southeast African Gohl, K. and Uenzelmann-Neben, G.: The crustal role of the Agulhas Plateau, southwest Indian Francis, T. J. G. and Raitt, R.Fromm, T.: W.: AWIForge Seismic refraction measurements in the southern Indian Davy, B., Hoernle, K., and Reinhard, W.: Hikurangi Plateau: crustal structure, rifted for- Gladczenko, T. P., Co 5 5 30 25 20 30 15 25 15 20 10 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , , 2013. , 2006. 10.1111/j.1365- www.soest.hawaii. , 1997. (last access: 22 Jan- , 1992. ” to the Manihiki Plateau , F.: Osbourn Trough: struc- , 1998. ff Sonne 10.1016/S0031-9201(99)00122-3 10.1029/2012GC004448 , 2006. 10.1029/96JB03223 10.1016/j.epsl.2006.03.018 Fahrtbericht/Cruise Report SO225, GEO- , F., van den Bogaard, P., Michael, P., Cof- ff Sonne 1887 1888 , 2001. ers, P., Kuhn, T., and Hau ff , F.: R/V 10.1111/j.1365-246X.1992.tb00836.x ff , 1995. , 2004. , 2011. , 1974. , 2005. 10.1126/science.282.5397.2241 , 2010. 10.1016/j.epsl.2005.11.049 , 1999. http://www.soest.hawaii.edu/users/bzelt/zp/zp.html , 2008. 10.1029/95JB01585 , available from: 10.1016/j.epsl.2011.01.025 10.1016/S0012-8252(00)00037-4 10.1029/JB084iB11p06003 10.1016/j.epsl.2005.02.004 10.1029/1999GL900391 10.1029/2009GC002935 10.1016/j.tecto.2003.09.029 in 2012 (So 224), Reports of Polar and Marine Research, 2012. fin, M. F., andSW Koppers, Pacific: A. A. newdoi: P.: Age evidence and for geochemistry a of the plume oceanic origin, Manihiki Earth Plateau, Planet. Sc. Lett., 304, 135–146, Geophys. J. Int., 108, 16–34, doi: Science, 282, 2241–2243, doi: Sc. Lett., 241, 372–380, doi: ture, geochemistry and implicationsPacific, of Earth a Planet. mid-Cretaceous Sc. paleospreading Lett., ridge 245, in 685–701, the doi: South edu uary 2014), 2004. Kelts, K., Martini, E., McNulty,Project, C., 33, and 1–354, Winterer, E. 1976. L.: Inital Reports of the Deep Sea Drilling doi: and acousticdoi: stratigraphy of the Manihiki Plateau, Deep-Sea Res., 21, 793–813, Farallon triple junction indoi: the South Pacific Ocean, Earth Planet.MAR Sc. Reports, 1–176, Lett., 2013. 233, 179–194, 17,585, doi: dian Ocean: new evidencedoi: for excessive volcanism, Geophys. Res. Lett., 26, 1941–1944, 2000. and the petrologicdoi: evolution of flood basalts,altimetry, Geochem. J. Geophys. Geophy. Res., 102, Geosy., 10039–10054, 11, doi: Q09006, evolution of a large igneous province, Geophys. J. Int., 174, 336–350,placement doi: history seen inpreparation, high 2014. resolution seismic reflection data, Earth Planet. Sc.Petrological Lett., in interpretationprovinces, of Geochem. Geophy. Geosy., 14, deep 604–619, doi: crustal intrusiveJava Plateau, bodies Phys. Earth beneath Planet. Int., oceanic 118, hotspot 29–51, doi: Island Arc fromdoi: ocean bottom seismometer–airgun data, Tectonophysics, 389, 191–220, 246X.2008.03808.x Uenzelmann-Neben, G.: The expedition of the research vessel “ Timm, C., Hoernle, K., Reinhard, W., Hau Taylor, B.: The single largest oceanic plateau: Ontong Java–Manihiki–Hikurangi, Earth Planet. Zelt, B.: zp – Software for plotting & picking SEGY seismic refractionZelt, data, C. A. and Smith, R. B.: Seismic traveltime inversion for 2-D crustal velocity structure, Worthington, T. J., Hekinian, R., Sto Tarduno, J. A.: Evidence for extreme climatic warmth from Late Cretaceous arctic vertebrates, Wignall, P. B.: Large igneous provincesWinterer, and E. mass L., extinctions, Earth-Sci. Lonsdale, Rev., 53, P. 1–33, L., Matthews, J. L., and Rosendahl, B. R.: Structure Schlanger, S. O., Jackson, E., Boyce, R. E., Cook, H., Jenkyns, H. C., Johnson, D., Kaneps, A., White, R. S. and McKenzie, D.: Mantle plumes and flood basalts, J. Geophys. Res., 100, 17543– Werner, R., Nürnberg, D., and Hau Viso, R. F., Larson, R. L., and Pockalny, R. A.: Tectonic evolution of the Pacific–Phoenix– Uenzelmann-Neben, G., Gohl, K., Ehrhardt, A., and Seargent, M.: Agulhas Plateau, SW In- Sandwell, D. T. and Smith, W. H.: Marine gravity anomaly from Geosat and ERS 1 satellite Ridley, V. A. and Richards, M. A.: Deep crustal structure beneath large igneous provinces Richards, M. A., Contreras-Reyes, E., Lithgow-Bertelloni, C., Ghiorso, M., and Stixrude, L.: Richardson, W. P.,Okal, E. A., and Van der Lee, S.: Rayleigh–wave tomography of the Ontong– Parsiegla, N., Gohl, K., and Uenzelmann-Neben, G.: ThePietsch, Agulhas R. and Plateau: Uenzelmann-Neben, structure G.: and The Manihiki Plateau – a multistage volcanic em- 5 5 30 25 20 20 15 10 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 1890 1889 ] (Hamilton, 1978) used for specific layers in the gravity anomaly 2 − Layersedimentslow velocity upper crustupper crust 2400upper middle crustmiddle crustlower middle crust 2050lower AWI-20120100 crust 2800mantle AWI-20120200 not present 2650 2950 2900 2050 2900 3130 2800 2950 not 3300 present 3150 3300 Bathymetric map of the central western Pacific, refraction/wide-angle refraction seis- Rock densities [kg m Figure 1. Table 1. mic lines of cruisegrey. So-224 Yellow stars are depict showncomponents in the of red, positions the reflection of OntongHikurangi seismic Java the (H.) lines Nui and OBS-stations. of are Manihiki In So-224 (M.)). shownOsbourn The are Trough the at (O. green T.) shown and their inlet lines the in current indicate Ellice mapshown Basin position the in the (E. former (Ontong B.). the spreading The three larger Java dark centers map. (O. main J.), green of box the indicates the study area model. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | st16 representing the st08 representing the (a) (a) st32 representing the Danger Island Troughs (b) 1892 1891 st32 representing the Danger Island Troughs area. wave arrivals (AWI-20120100) at wave arrivals (AWI-20120100) at S P (b) Data examples for Data examples for area. western part of the Western Plateaus and Figure 3. Figure 2. central Western Plateaus and Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | st18 representing the st08 representing the (a) (a) 1894 1893 st19 representing the central High Plateau. (b) wave arrivals (AWI-20120200) at wave arrivals (AWI-20120200) at S P st29 representing the Manihiki Scarp area. (b) Data examples for Data examples for western margin of the High Plateau and Figure 5. Figure 4. central High Plateau and Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 1896 1895 wave velocity model of AWI-20120100; the grey transparent areas are not covered wave velocity model of AWI-20120100; the grey transparent areas are not covered S P Figure 7. by rays. The locationsblack of (malfunctioning station) OBS stars stations on are theis map. shown indicated The in with resolution the calculated the lower for yellow right the corner. (functioning velocity nodes station) and Figure 6. by rays. White layer boundariesstations is are indicated constraint with by the yellowon wide-angle (functioning the reflections. station) map. and The The black location resolution (malfunctioning of station) calculated stars OBS for the velocity nodes is shown in the lower right corner. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 1898 1897 wave velocity model of AWI-20120200; the grey transparent areas are not covered wave velocity model of AWI-20120200; the grey transparent areas are not covered S P Figure 9. by rays. The locationsblack of (malfunctioning station) OBS stars stations on are theis map. shown indicated The in with resolution the calculated the lower for yellow right the corner. (functioning velocity nodes station) and Figure 8. by rays. White layer boundaries arestations constrained by are wide-angle reflections. indicated The locations withstars of OBS on the the yellow map. (functioningcorner. The station) resolution and calculated black for (malfunctioning the station) velocity nodes is shown in the lower right

st29

] [kg/m in Density

] [mgal Gravity 3 st28 0.35 0 0 50 50 st27 −10 −20 −30 −40 −50 −60 −70 −80 −90 90 80 70 60 50 40 30 20 10 0 400 400 400 400 Scarp Manihiki st26 2950 st25 0.32 450 450 st24 −7˚ −8˚ −9˚ −10˚ 350 350 350 350 0.30 st23 400 400 σ] 3130 34 0.28 st22 33 50 50 −164˚ −164˚ 31 st21 300 300 300 300 32 0.26 29 30 27 3003 3003 28 st20 0.24 2050 25 26 23 24 250 250 250 250 2400 st19 0.22 −165˚ −165˚ 50 50 21 1900 1899 22 Distance [km] 19 st18 Distance [km] 20 2950 0.20 Poisson’s ratio [σ] ratio Poisson’s 02 02 High Plateau 18 20 16 20 st16 14 200 200 200 200 transport of ma c material basalt 15 st15 12 2800 −166˚ −166˚ 13 150 150 2650 10 st14 11 8 9 AWI−20120200 Poisson’s Ratio [ AWI−20120200 st13 3300 6 7 150 150 150 150 2900 100 100 st12 4 5 st11 2 3 −167˚ −167˚ 0 0 st10 1 st9 100 100 100 100 0.10 st8 05 st7 05 −7˚ −8˚ −9˚ −10˚ 0 0

−5 50 40 30 20 10

st6 −10 −15 −20 −25

−10 −20 −30 −40 −50 Depth [km] Depth wave model and therefore cannot return reliable values for the Poisson’s ratio. [mGal] Gravity st5 S 0 0 0 0 st4 Calculated Poisson’s ratio for AWI-20120200; grey shaded areas are not covered st3 Gravity model of AWI-20120100 upper panel: freeair gravity anomaly (Sandwell and st2 basalt st1

Samoan Basin

. 0

0505 05 05

2 2

W 0 5 0

10 15 20 25 30 10 20 30 Depth [km] Depth Figure 11. Smith, 1997) middlepanel: panel: gravity measured model for anomaly AWI-20120100. in blue calculated anomaly in orange, lower White dashed lines indicate areas of higher Poisson’s ratio. Figure 10. by rays in the

SE 500500 500500 Gravity [mGal] Gravity 2650 2800 2900 2950 3100 3300 3400 2000 2400 st34 LIP-crust

„standard“ „standard“

High Plateau Density in [kg/m in Density

0 ] st33 3 basaltic ows 90 80 70 60 50 40 30 20 10 450450 450450 −10 −20 −30 −40 −50 −60 −70 −80 −90 gabbro mac intrusions st32 500 500 st31 3300 Moho −11˚ −12˚ −13˚ −14˚ st30 rift Troughs failed st29 Danger Island 400400 400400 −159˚ −159˚ 450 450 st28 st27 2050 st26 400 400 350350 350350 34 −160˚ −160˚ st25 33 32 st24 31 30 29 sediments 50 50 st23 28 27 26 st22 25 300300 300300 −161˚ −161˚ 24 st21 03 03 23 high velocity layer high velocity 30 st20 2900 30 22 21 st19 20 st18 250250 250250 −162˚ −162˚ 2950 19 3150 250 250 mantle 1902 1901 Western Plateaus Western st16 18 Distance [km] Distance [km] 2800 16 Distance [km] sedimentary basins and thinned LIP-crust AWI−20120100 15 st15 14 200 200 13 200200 200200 sediments 2900 st14 12 −163˚ −163˚ 11 10 st13 9 8 st12 7 6 150 150 2800 5 st11 4 150150 150150 3 −164˚ −164˚ 2 st10 1 st9 mac intrusions 100 100 Moho st8 st7 100100 100100 extensional faulting −165˚ −165˚ 0 0 stretched LIP-crust with stretched st6 st5 3300 st4 gabbro 00 00 05 05 st3 −166˚ −166˚ 0 0 Gravity model of AWI-20120200 upper panel: free-air gravity anomaly (Sandwell

50 40 30 20 10 Sketch of geological interpretation of AWI-20120100, black lines indicate fault sys-

−5

−10 −20 −30 −40 −50

−10 −15 −20 −25 Gravity [mGal] Gravity Depth [km] Depth st2 −11˚ −12˚ −13˚ −14˚ st1 oceanic crust oceanic Basin Tokelau Tokelau transition to normal to transition basaltic ows 0505 0505

NW 00 5

10 10 15 20 20 25 30 30 Depth [km] Depth Figure 12. and Smith, 1997) middle panel:panel: measured anomaly gravity in model blue for calculated AWI-20120200. anomaly in orange, lower Figure 13. tems.

Depth [km] Depth P-wave velocity [km/s] velocity P-wave 00 5 10 10 15 20 20 25 30 30 4.5 5.0 5.5 6.0 6.5 7.0 7.5 E 500500 500500 st34 5.0 6.7 7.1 8.1 st33 crust [1993] altered altered Mussett Brown and Brown st32 oceanic crust oceanic normal oceanic normal oceanic Penrhyn Basin Penrhyn 450450 450450 st31 serpentinized crust serpentinized st30 [2012] 4.5 5.5 5.5 6.5 7.0 7.5 7.9 Gohl et al. Gohl et al. st29 Ridge Mozambique Mozambique st28 st27 400400 400400 gabbro N-S trending shearing zone st26 Manihiki Scarp 5.1 5.8 6.4 6.8 7.1 7.2 8.1 st25 [2008] Parsiegla et al. et al. Parsiegla (north/central) Agulhas Plateau Agulhas Moho st24 350350 350350 st23 4.9 6.6 6.6 7.0 7.2 7.6 8.1 Gohl and (south) Neben [2001] st22 - Uenzelmann Agulhas Plateau Agulhas 300300 300300 st21 4.7 6.7 6.6 7.4 8.0 (north) Plateau center Kerguelen Kerguelen st20 Charvis and volcanic volcanic Operto [1999] 250250 250250 st19 mac intrusions mantle center 1904 1903 5.8 6.0 6.4 7.3 8.1 volcanic volcanic Ridge Distance [km] Distance [km] Broken Broken st18 Francis and Francis Raitt [1967] Raitt High Plateau AWI−20120200 high velocity layer high velocity „standard“ LIP-crust with „standard“ st16 200200 200200 center st15 4.0 5.8 6.1 7.1 8.2 volcanic volcanic [2004] (south) Plateau Miura et al. et al. Miura st14 Ontong-Java Ontong-Java st13 mac intrusions 150150 150150 st12 magmatic supply pathways connected to local volcanic centers local volcanic connected to supply pathways magmatic 4.5 5.8 7.0 7.7 8.6 (north) Plateau [1976] st11 center Ontong-Java Ontong-Java volcanic volcanic Furumoto et al. al. et Furumoto st10 st9 100100 100100 st8 7.4 4.9 5.4 5.7 6.2 6.7 6.8 7.1 8.2 st7 High Plateau this study Manihiki Plateau gabbro st6 rifted st5 margin 00 00 Moho st4 4.4 5.1 6.3 6.7 7.2 7.6 8.2 Comparison of the crustal structure of the Western Plateaus and the High Plateau st3 Sketch of geological interpretation of AWI-20120200, white arrows indicate areas of this study st2 Manihiki Plateau Western Plateaus Western basaltic ows st1 Samoan Basin normal oceanic crust oceanic 0505 05 05 W

00 5

0 5 10 15 30 35 40 45 20 10 10 15 20 20 25 30 30 Depth [km] Depth Crustal thickness [km] thickness Crustal with other oceanic LIPs.velocity zone The of grey the shadedis lower areas depicted crust in is represent the represented the yellow in and sedimentary the orange cover. blue colors. The colors. The high transitional crustal layer Figure 15. Figure 14. magmatic upwelling, black solid lines indicate fault systems. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | plateaus plateaus tion at HP tion at at Manihikiat Scarp Ontong-Java-Nui Ontong-Java-Nui „Super-LIP“ event alkalic DIT basalts at initial rifting stage: Sedimentation Sedimentation WP at post volcanic stage: post volcanic Sedimentation Sedimentation on WP rst volcanic stage: rst volcanic massive transform fault transform massive crustal stretching at WP at crustal stretching and the Manihiki Plateau rifting of Ontong-Java-Nui rifting of Ontong-Java-Nui seamount volcanism on HP volcanism seamount massive volcanism creating creating volcanism massive matic overprint on both sub- overprint matic unsual element patterns at DIT at patterns unsual element late secondary volcanic stage: secondary volcanic late

creation of tholeiitic basalts with of tholeiitic creation

sedimentary cover on HP and WP on HP and sedimentary cover termination of tectonic and mag- termination early secondary volcanic stage: secondaryearly volcanic erosion of former volcanic centers volcanic former of erosion

- and sedimenta volcanism localized uplift subsidence subsidence faulting transform transform faulting transform transform faulting transform transform HP HP 1905 HP HP erosion DIT DIT DIT DIT WP WP WP Ontong-Java Nui Ontong-Java WP crustal stretching crustal stretching crustal stretching OJP OJP Ontong-Java-Plateau WP DIT Plateaus Western HP Danger Island Troughs TB High Plateau Basin Tokelau TB TB TB Sketch of the evolution of the Manihiki Plateau with special focus on the High Plateau Figure 16. and the Western Plateaus from the early Cretaceous to the current setting.