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Aspects of New Zealand Sedimenta4on and Tectonics Kathleen M. Marsaglia! California State University Northridge! [email protected]! and! Carrie Bender, Julie G. Parra, Kevin Rivera, Adewale Adedeji, " Dawn E. James, Shawn Shapiro, and Alissa M. DeVaughn" (California State University Northridge)! Mike Marden (Landcare), Nick Mortimer (GNS). ! J.P. Walsh (East Carolina University), Candace Martin (Otago U.),! Lionel Carter (NIWA, Victoria U.)! ! Acknowledgments • C. Alexander, B. Gomez, S. Kuehl, A. Orpin, and A. Palmer • Funded by NSF GEO-0119936 & GEO-0503609 h#p://ocean.naonalgeographic.com Image from CANZ (1996) New Zealand vs. “Zealandia” (see Mor-mer, 2004; Gondwana Research) OVERVIEW of TALK •! General overview of NZ Paleozoic to Cenozoic(meta)sedime ntary units emphasizing conVergent margin history •! North Island Cenozoic – sedimentary record of Oligo-Miocene subducon incep4on and Hikurangi margin deVelopment Youngest sediments and oldest sedimentary rocks related to subducon New Zealand Basement Rocks (Mor-mer, 2008) Image from NIWA" Modern Continental Margin Example of # Subduction Inception# South Island, NZ # North" (Sutherland et al., 2006) Island" Solander Island ”Arc”? South" Island" Puysegur Trench Solander Small-scale Islands Version of Upli/erosion what Puysegur then Quaternary Ridge may have subsidence looked like Beehive Island New Zealand Basement Rocks (Mor-mer, 2008) Nelson Q-map by See GeoPRISMS White Paper by Pound et al. on Takaka Terrane Raenbury et al. (1998) 200 Ma Triassic/Jurassic Gondwana (Antar-ca/Australia) 250 Ma Permian 100-55 Ma to schist Late Cretaceous/ Early Ter-ary Zealandia Tectonic History • Ac2ve-margin ! subduc2on in Permian (older?) • Followed by ri?ing and ! passive-margin formaon in Cretaceous • Ac2ve (! subduc2on and transform) margin in Illustraons by G. Cox from Coates (2002) Cenozoic (complex The Rise and Fall of the Southern Alps evoluon) Rangitata R. Waitaki R. upper Clutha River Clutha R. Bounty/Canterbury Sedimentary Coates (2002) System: SOURCE upper Clutha River Rangitata River Coates (2002) CM BT Passive Margin History preserved in Bounty Trough (BT)and Canterbury Margin (CM) but with Alpine Fault Influence Image from CANZ (1996) Canterbury Stragraphy: 3. Miocene - Recent (MR) Post-ri?, Cretaceous to Recent Regression first-order, tectonically- • Regression in late Oligocene or ! controlled, transgressive- early Miocene: ini-aon of Alpine regressive cycle. Fault movement increased sediment supply. • UpliZ of the Southern Alps ! accelerated at ∼8-5 Ma or ∼10-8 Ma indicang an increased component of convergence. • This transpression led to a further ! ri increase in sediment supply to the offshore basin. MR O 2. Oligocene Highstand (O) CP Marshall Paraconformity Ini-aon of strong ocean currents MR O 1. Cret.-Paleogene (CP) CP Transgression Summary from C. Fulthorpe DWBC 11.0-3.5 Ma hiatus at Site 1122 during me of Alpine upli? and sealevel lowstand Cause(s)? Submarine erosion (DWBC) & decrease in sediment input owing to onshore fluvial drainage disrupon and LAKE formaon Marsaglia et al. (2011; Geosphere) Subducon ini-aon in Oligocene/ Miocene in Northern North Island ul-mately evolving into modern Hikurangi Subducon Zone Image from CANZ (1996) Late Oligocene (c. 25 Ma) paleogeography Evidence for upli and exposure from King et al. (1999) (islands)… 1) During subducon ini-aon? Unknown? 2) During allochthon emplacement? Ihungia Igneous Conglomerate? Alternate view No land area during Late Oligocene Timing of Events Northland Arc Magma4sm Max. Marine Ma Inunda4on Northland Allochthon Emplacement Pre-TVZ? Subducon Iniaon? V Miocene volcanic centers Allochthon-related igneous rocks Ihungia Ophiolite part of allochthon Outcrops arguably obducted during process of subducon " " ! Observations of Ihungia igneous conglomerate:! ! Ø! In Lower Tolaga Group" Ø! Occurs as isolated, small" outcrops (<1km2)" Ø! Adjacent to faulted(?)" contacts with allochthon" Ø! 10-15m thick conglomeratic" intervals" Ø! Outer shelf to slope deposits " Ø! Channelized, discontinuous" Ø! Normal grading, NW source" Ø! Wood and plant debris" Ø! Associated with mélange," debris flows & sedimentary " breccia " " # Map simplified from Mazengarb and Speden (2000) Gravel " Clast " Counts" (n=100)" DS short axis DI intermediate axis DL long axis Serpenne Metamorphic Volcanic Sandstones Contain Serpen-nite Sedimentary Clasts! Serpenne 0.5 mm 0.5 mm Matakaoa Submarine Instability Complex Joanne et al. (2010) (slump / debris avalanche / debris flow) B secon MDA = Matakoa Debris Avalanche ? Ao5cm 34 Ihungia re-entrant explains: > Nature of contact > Distribu-on of gravel > Debris flows / breccia beds > Distribu-on of mélange > Large block of allochthon > Offshore seismic character > Distribu-on of Miocene seep imestones in this basin Hikurangi Convergent Margin •! The Cretaceous Hikurangi oceanic plateau, part of the Pacific Plate, is being subducted beneath the eastern North Island, New Zealand at the Hikurangi Trough. Waipaoa River Sedimentary System •! Convergence rates range from 4-6 cm/yr in the north to 2-4 cm/yr at southern end. •! The northern Hikurangi margin is relavely sediment-starved, with <1km of sediment blanke-ng the incoming Hikurangi plateau. •! Offshore tectonics are dominated by subduc-on erosion and seamount subducon. Adapted from Barnes et al. (2010) Adapted from Barnes et al. (2010) SOURCE Waipaoa Sedimentary System SINK Mazengarb and Speden (2000) TARNDALE SLIP Q Very Fine Very Coarse F Mazengarb and Speden (2000) L Poverty Shelf - Sink/Source/Transfer zone? mud, sand, and graVel Mud Mud Coastal cliff erosion of Miocene sedimentary rocks •Narrow sandy beaches ! Parra et al. (2012; Sedimentary Geology) Poverty Slope & Hikurangi Trough: WSS SINK Poverty NIWA Shelf Short Piston Adedeji (in prep) Core Adedeji Poverty (in prep) Shelf RV Marion Adedeji Dufresne (in prep) Long Piston Cores Poverty Shelf Mixed Waipaoa River modified from Alexander et al. (2010) Effects of Seamount Subducon - Seismic Interpretaon by Pedley et al. (2010) Parra et al. (2012) • ! Gravel made up of Torlesse lithologies. •No ! Torlesse exposed in Waipaoa River Basin or on an-clines. • ! Torlesse gravel implies WSS not a closed system Torlesse gravel Sandy low tombolo on beaches in connecng Mahia Hawke’s Bay Peninsula to mainland 5 cm Hawke Bay Torlesse Beach Gravel Parra et al. (2012) Di/Dl Poverty Shelf Box-core Gravel Ds/Di Did lowstand river system extend from Hawke Bay across or around Mahia Peninsula to Poverty Shelf? Probably… System not closed! Torlesse outcrop mp mp Parra et al. (2012) Paquet et al. 2009 Image from CANZ (1996) Taranaki Basin (Courtesy of NZPAM.) Clas-c provenance reflects change from Cretaceous riZed margin to Miocene/ Recent retroarc foreland basin Image from CANZ (1996) Thank you for your aen-on Quesons? Waipaoa Sedimentary System: Drivers, processes and responses (Carter et al., 2010, Marine Geology v.270) Modified from Carter et al. (2010) Taupo Waipaoa Poverty Hikurangi Magmac arc River Bay, Shelf, Slope Trench Pedley et al. (2010) Note modern Lake & terrace coastline used! deposits LAKE Offshore implicaons: sediment derived from upliZ, decrease river input, lake ouxlow deposit(s)? Moki Interval (14 Ma) Paleogeography Submarine fan sinks Source(s)? Onshore fluvial drainage? (courtesy of P. King, GNS) Doran (in prep.) Ihungia Clast Geochemistry! > Basaltic andesite to gabbro > Mainly tholeiitic & subalkalic > Trace element composition:" a) intermediate between MORB & arc" basalt with mild slab fluid signature" b) unlike Hikurangi Plateau, Cret. MORB" and Northland Arc" c) similar to Tangihua & Matakaoa Ign." # Matakaoa Tangihua Igneous Igneous Rocks Rocks V Miocene volcanic rocks Allochthon-related igneous rocks Concentraon of Miocene seep limestones in Ihungia ‘basin’ Nyman et al. (2010) Saether et al. (2010) Sand/Sandstone Detrital Modes Similar to those from Cyprus! (Matakaoa) Cyprus beach & stream sand from Garzan et al. 2000 Geological Map of Cyprus Geological SurVey Dept., Cyprus (1995) S S S Kouris River S Rangitata R. Waitaki R. Bounty Channel & Fan ODP Site 1122 Clutha R. ODP Site 1122 50 km ~4500 m water depth levee Mean value Pleistocene to Miocene Individual samples 620 m Conclusion: Shapiro et al. (2007) Clutha River is the main source of sand GSA Spec. Pap. 420 delivered to Bounty Fan Late Oligocene (c. 25 Ma) paleogeography from King et al. (1999) Alternate view: No land area during Late Oligocene Taranaki Basin - many Waipaoa - one Canterbury/Bounty - a few Image from CANZ (1996) Waipaoa SS! Focus Site! (actively deforming! forearc)! New paradigm for modeling sedi- ment producon, transport & depo- sion; closed systems allow for sediment budget calculaons. Embraced by the Petroleum Indus. HIKURANKI REENTRANT STUDIES 1) Source-to Sink in Poverty Summary Reentrant Modern Waipaoa Sedimentary System (WSS) Source ( River) to Sink (Poverty re-entrant & Hikurangi Trench) 2) Ihungia Miocene Reentrant Miocene Subducon & Forearc Development Reentrants Ihungia Conglomerate 3) IODP Drilling Proposal Seamount subducDon. slow- slip events, reentrant sedimentaDon and tectonics Deposional model must explain: > Subaerial indicators (clast shape, wood debris) > Limited sedimentary structures > Northwestern(?) source from deeper (mantle?) levels > Associaon with mélange, debris flows & sedimentary breccia > Gravel-sized clasts in deep water > Limited occurrence > Contact with allochthon (normal fault, sheared, vs. unconformity) .
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  • The Age and Origin of Miocene-Pliocene Fault Reactivations in the Upper Plate of an Incipient Subduction Zone, Puysegur Margin

    The Age and Origin of Miocene-Pliocene Fault Reactivations in the Upper Plate of an Incipient Subduction Zone, Puysegur Margin

    RESEARCH ARTICLE The Age and Origin of Miocene‐Pliocene Fault 10.1029/2019TC005674 Reactivations in the Upper Plate of an Key Points: • Structural analyses and 40Ar/39Ar Incipient Subduction Zone, Puysegur geochronology reveal multiple fault reactivations accompanying Margin, New Zealand subduction initiation at the K. A. Klepeis1 , L. E. Webb1 , H. J. Blatchford1,2 , R. Jongens3 , R. E. Turnbull4 , and Puysegur Margin 5 • The data show how fault motions J. J. Schwartz are linked to events occurring at the 1 2 Puysegur Trench and deep within Department of Geology, University of Vermont, Burlington, VT, USA, Now at Department of Earth Sciences, University continental lithosphere of Minnesota, Minneapolis, MN, USA, 3Anatoki Geoscience Ltd, Dunedin, New Zealand, 4Dunedin Research Centre, GNS • Two episodes of Late Science, Dunedin, New Zealand, 5Department of Geological Sciences, California State University, Northridge, Northridge, Miocene‐Pliocene reverse faulting CA, USA resulted in short pulses of accelerated rock uplift and topographic growth Abstract Structural observations and 40Ar/39Ar geochronology on pseudotachylyte, mylonite, and other Supporting Information: fault zone materials from Fiordland, New Zealand, reveal a multistage history of fault reactivation and • Supporting information S1 uplift above an incipient ocean‐continent subduction zone. The integrated data allow us to distinguish • Table S1 true fault reactivations from cases where different styles of brittle and ductile deformation happen • Figure S1 • Table S2 together. Five stages of faulting record the initiation and evolution of subduction at the Puysegur Trench. Stage 1 normal faults (40–25 Ma) formed during continental rifting prior to subduction. These faults were reactivated as dextral strike‐slip shear zones when subduction began at ~25 Ma.