Macrofossil biofacies in the late Neogene of central Hawke's Bay: applications to palaeogeography

Figures & data

Figure 1 Simplified geological map (in New Zealand stages) of the central and western Hawke's Bay area (after Bland 2006) showing the distribution of macrofossil observation and sample sites used in this study, and the locations of places referred to in the text. Tolaga Group rocks are of Otaian–early Opoitian age (Early Miocene–Early Pliocene). The Mangaheia Group comprises all rocks of late Opoitian–Nukumaruan age (Early Pliocene–Pleistocene). AS, Awapai Station; CC, Cape Kidnappers; CF, Crohane Forest; DT, Dartmoor; FR, Flag Range; KS, Kikowhero Stream; Kuri., Kuripapango; MR, Mason Ridge; MT, Matapiro; OD, Ohara Depression; OM, Omahaki Depression; OS, Opau Stream; OT, Otamauri; PK, Pukehamoamoa; PP, Pakipaki; PT, Patoka; SH, Sherenden; SI, Scinde Island; SR, Sandy Ridge; SV, Seaview Station; TG, The Gums; TQ, Tangoio Quarry; TS, Tarawera Station; TW, Te Waka Range; WB, Whirinaki Beach; WiB, Waipatiki Beach; WR, Wakarara Range. INSET: Rau. Pen., Raukumara Peninsula.

Figure 2 Simplified chronostratigraphic columns for western Hawke's Bay (after Bland 2006), showing geological units mentioned in this paper and their general lithological characteristics. DE, Devils Elbow Mudstone Member; TN, Te Ngaru Mudstone Member; TG, Tangoio Limestone Member; MR, Mairau Mudstone Member; DS, Darkys Spur Member; PKI, Park Island Limestone Member; AP, Aropaoanui Mudstone Member; TU, Tutira Member; WP, Waipunga Formation; MU, Makaretu Mudstone; TO, Te Onepu Limestone; RU, Raukawa Mudstone; RO, Rotookiwa Limestone; PE, Pukekura Calcarenite; AW, Awapapa Limestone; MP, Mokopeka Sandstone; KR, Kairakau Limestone. For more details on stratigraphic units refer to Beu (1995), Bland et al. (2007) and Lee et al. (2011).

Table 1 Summary of lithofacies in the Neogene succession cropping out in western and central Hawke's Bay (refer to Bland 2006 for discussion on individual lithofacies). Lithofacies are grouped into siliciclastic, bioclastic or mixed bioclastic-siliciclastic groups. Siliciclastic lithofacies are further sub-divided into four assemblages, primarily on the basis of grain size (sandstone, siltstone, conglomerate and volcaniclastic assemblages). A, abundant; C, common; R, rare; S, some; UC, uncommon. Faunal associations are summarised in Table 2.

Lithofacies		Description	Inferred environment of deposition	Typical faunal associations
Sandstone lithofacies group
S1	Massive sandstone (C)	Massive, non-cemented non-fossiliferous slightly micaceous very well-sorted fine to medium sandstone.	Shoreface to nearshore	None
S2	Massive to cross-stratified sandstone (C)	Massive to cross-stratified non-cemented very well-sorted fine to medium sandstone.	Shoreface to inner shelf	None
S3	Massive to cross-stratified fossiliferous sandstone (C)	Massive to cross-stratified non-cemented very well-sorted moderately to highly fossiliferous fine to medium sandstone. Macrofossils commonly concentrated into densely fossiliferous lenses.	Shoreface to inner shelf	Dosinia, Zethalia, Fellaster
S4	Silty sandstone (C)	Non-cemented non- to sparsely fossiliferous massive to laminated well-sorted fine sandstone to silty sandstone.	Lower-inner to middle shelf	Atrina, Mactra (Maorimactra), Dosinia (Kereia), Patro
S5	Calcareous sandstone (S)	Non- to well-cemented non- to sparsely fossiliferous slightly to moderately calcareous fine sandstone with prominent concretions and cemented horizons. May contain a noticeable bioclastic content.	Lower-inner to middle shelf	Atrina
S6	Interbedded sandstone-siltstone (S)	Non- to well-cemented non- to sparsely fossiliferous fine sandstone to sandy siltstone with common concretionary horizons and prominent sandstone and siltstone interbeds.	Inner shelf	Dosinia (Kereia), Atrina
S7	Sandstone with siltstone stringers (UC)	Non- to well-cemented fine sandstone to sandy siltstone with common mudstone stringers. Beds are faintly to strongly laminated.	Marginal-marine to sheltered nearshore	Austrovenus, Patro
S8	Ripple and flaser-bedded sandstone (R)	Non- to slightly fossiliferous ripple, flaser- and cross-bedded fine to medium sandstone with common interbeds and detached lenses of siltstone.	Estuarine	Austrovenus
S9	Pebbly sandstone (S)	Non-cemented, non- to moderately fossiliferous massive to cross-stratified to laminated sandstone with common to abundant Torlesse terrane greywacke pebbles and conglomerate lenses.	Shoreface to nearshore	Dosinia, Zethalia
S10	Concretionary sandstone (S)	Non- to slightly cemented non- to sparsely fossiliferous moderately to strongly laminated and cross-stratified fine to medium sandstone with common to abundant concretionary horizons.	Nearshore to inner shelf	Atrina
S11	Sandstone with fossiliferous concretions (S)	Slightly to well-cemented fine to medium sandstone with moderately to highly fossiliferous, moderately to well-cemented concretionary bodies up to 1 m thick.	Nearshore to inner shelf	Struthiolaria (Callusaria), Zeacolpus
S12	Laminated to convolutedly bedded sandstone (R)	Strongly laminated to cross-stratified to convolutedly bedded fine to medium sandstone bodies in a series of stacked packages up to 0.5 m thick. Contains common to abundant tephric sediments.	Inner shelf	None
Siltstone lithofacies group
Z1	Massive siltstone (A)	Non-fossiliferous, massive to weakly laminated non- to slightly cemented siltstone. May contain concretions up to 1 m across.	Outer shelf to bathyal	None
Z2	Fossiliferous siltstone (A)	Slightly to moderately fossiliferous, massive to laminated non-cemented firm bioturbated siltstone.	Middle to outer shelf	Pratulum, Neilo, Ostrea, Tawera-Patro, Talochlamys, Notosaria-Talochlamys
Z3	Fossiliferous sandy siltstone	Slightly to moderately fossiliferous massive to laminated bioturbated siltstone.	Lower-inner to middle shelf	Atrina, Patro, Dosinia (Kereia), Stiracolpus-Talochlamys, Tawera-Patro
Z4	Siltstone with sandstone interbeds (UC)	Non- to moderately fossiliferous siltstone with sandstone interbeds and stringers. Ripple- and flaser-bedded units are common.	Estuarine	Austrovenus
Z5	Pebbly siltstone (C)	Non-cemented, slightly to moderately fossiliferous, slightly to moderately pebbly siltstone to sandy siltstone.	Inner to middle shelf	Stiracolpus-Talochlamys, Ostrea, Neilo
Z6	Siltstone-sandstone couplets	Slightly to strongly laminated planar-bedded non-cemented, fine to large-scale alternating fine siltstone/sandstone couplets.	Upper bathyal	None
Z7	Channelised siltstone-sandstone couplets (S)	Strongly laminated non-cemented alternating siltstone-sandstone couplets in large packages with sharp, highly erosional and channelised bases.	Upper bathyal	None
Z8	Siltstone with tephra beds (S)	Non- to slightly fossiliferous non-cemented sandy siltstone to siltstone with prominent discrete tephra beds.	Middle to outer shelf	Pratulum, Atrina, Talochlamys
Z9	Alternating siltstone-sandstone (C)	Alternating beds of non- to slightly fossiliferous non-cemented sandy siltstone interbedded with well-sorted non-fossiliferous fine sandstone.	Inner to upper- middle shelf	Dosinia (Kereia), Atrina
Z10	Siltstone with plant remains (R)	Non-cemented grey-brown laminated siltstone with some to abundant plant remains.	Non- to marginal-marine	None
Z11	Muddy shellbed (C)	Non- to weakly-cemented, massive siltstone to silty sandstone, matrix-dominated bed containing a concentration of molluscan macrofauna. May be noticeably pebbly in places. Inferred to occur above downlap surfaces.	Middle to outer shelf	Ostrea, Ostrea-glycymerid
Conglomerate lithofacies group
Cg1	Massive conglomerate (C)	Non- to moderately cemented, poorly to moderately sorted non-fossiliferous massive to weakly laminated greywacke-clast conglomerate. Clasts are of granule to boulder-size.	Fluvial braid-plain, river channels	None
Cg2	Conglomerate with sand and silt lenses (C)	Non- to slightly cemented massive to laminated and cross-stratified greywacke-clast conglomerate with interbeds of sandstone and siltstone to 0.5 m thick.	Fluvial braid-plain, major and adjacent channels	None
Cg3	Cross-stratified conglomerate (S)	Non- to slightly cemented, poorly to well-sorted tabular to trough cross-stratified greywacke-clast conglomerate.	Fluvial braid-plain, river channel bars	None
Cg4	Laminated conglomerate (C)	Strongly laminated very well-sorted alternating coarse sand/fine-pebble to medium/coarse pebble greywacke-clast beds.	Shoreface, shingle beach	None
Cg5	Slightly-fossiliferous conglomerate (UC)	Non- to moderately cemented clast-supported, slightly fossiliferous greywacke-clast conglomerate.	Marginal marine to estuarine	Austrovenus
Cg6	Fossiliferous conglomerate (S)	Non- to moderately cemented, moderately to well-sorted, moderately to highly fossiliferous greywacke-clast conglomerate.	Nearshore, embayment and tidal channels, inner shelf	Paphies, Zethalia, Tawera, Ostrea-glycymerid, Tucetona, Ostrea-Purpurocardia, Struthiolaria (Callusaria), Zeacolpus
Cg7	Fossiliferous breccia (R)	Non- to moderately cemented, poorly to slightly cemented, moderately to highly fossiliferous coarse-grained breccia. Clasts are dominated by greywacke with a sandy and gravelly matrix.	Nearshore to shoreface with a rocky coastline.	Crassostrea
Volcaniclastic lithofacies group
V1	Airfall tephra (R)	Non-welded, massive to laminated fine-ash with occasional fine to medium lapilli-sized clasts in beds up to 0.6 m thick. Commonly strongly burrowed.	Volcanic airfall into middle- to outer-shelf water depths	None
V2	Ignimbrite (R)	Non- to slightly welded, massive to laminated to cross-stratified fine ash with occasional medium lapilli-sized clasts.	Non-marine to marginal-marine pyroclastic flow	None
V3	Laminated to cross-stratified volcaniclastics (R)	Non-welded massive to strongly laminated and cross-stratified fine ash to medium lapilli-sized volcaniclastic sediments that display evidence of current re-working. Convolute bedding and water-escape structures are common.	Non-marine to estuarine	None
Bioclastic-dominated lithofacies group
BC1	Stacked medium to coarse skeletal beds (C)	Moderately to well-cemented, sparsely fossiliferous medium to coarse-grained stacked skeletal sheets 0.1–0.3 m thick.	Inner to middle shelf	Neothyris
BC2	Fossiliferous stacked medium to coarse skeletal beds (C)	Moderately to well-cemented moderately to highly fossiliferous stacked skeletal beds 0.1–0.3 m thick. Fauna are almost exclusively epifaunal and semi-infaunal taxa.	Inner to middle shelf	Crassostrea-Phialopecten, Neothyris
BC3	Shelly limestone (C)	Slightly to well-cemented moderately to highly fossiliferous shelly medium- to coarse-grained limestone with common to very abundant biomoulds.	Nearshore to inner shelf, tidal channels	Tucetona, Tawera, Eumarcia
BC4	Fossiliferous shell-gravel (S)	Slightly to moderately cemented highly fossiliferous cross-stratified shell-gravel-dominated coarse-grained sandstone with abundant intact macrofossils.	Nearshore to inner shelf	Tawera-Maoricrypta, Maoricrypta-Sigapatella
BC5	Giant cross-stratified limestone (UC)	Slightly to moderately cemented non- to sparsely-fossiliferous limestone with stacked beds as part of giant, metre-scale trough and sigmoidal cross-beds.	Inner to middle shelf with strong seafloor currents	Crassostrea-Phialopecten, Neothyris
BC6	Pebbly limestone (S)	Slightly- to well-cemented, sparsely to moderately fossiliferous alternating skeletal grainstone and mixed bioclastic-siliciclastic packstone as sheets up to 0.3 m thick with common to abundant greywacke pebbles.	Inner shelf, strong bottom currents	Crassostrea-Phialopecten
BC7	Cross-stratified sandy limestone (S)	Moderately to well-cemented tabular to sigmoidal cross-stratified sandy limestone. Contains sparse to common macrofauna, which are usually present as biomoulds.	Inner shelf, moderate to strong bottom currents	Tawera
Mixed bioclastic–siliciclastic-dominated group
MX1	Bioclastic-siliciclastic sandstone (C)	Non- to slightly-cemented, medium-grained siliciclastic-bioclastic sandstone. Commonly cross-stratified with mudstone lenses and stringers to 0.3 m thick.	Innermost shelf	Tawera, Tawera-Maoricrypta, Maoricrypta-Sigapatella
MX2	Coarse-grained mixed conglomerate (R)	Pebble to cobble-dominated conglomerate with rare clasts up to boulder size and common valves of robust epifaunal and infaunal bivalves in a coarse-grained bioturbated matrix of mixed bioclastic-siliciclastic sediments. Contains Mesozoic and Cenozoic clasts.	Nearshore, tidal channels	Crassostrea-Phialopecten
MX3	Conglomeratic limestone (S)	Moderately to well-cemented, massive to cross-stratified medium- to coarse-grained bioclastic-dominated beds with common to abundant pebble to cobble-sized clasts of greywacke, sandstone and mudstone lithologies.	Nearshore, embayment and tidal channels, inner shelf	Tawera, Paphies, Maoricolpus, Tucetona, Ostrea-glycymerid, Struthiolaria (Callusaria), Zeacolpus, Ostrea-Purpurocardia
MX4	Alternating bioclastic-siliciclastic bodies (C)	Slightly to well-cemented sparsely fossiliferous alternating skeletal grainstone and mixed bioclastic-siliciclastic packstone as sheets up to 0.3 m thick.	Inner to middle shelf with strong tidal currents	Neothyris

Table 2 Summary of Neogene macrofaunal associations identified in this study for Late Miocene–Pleistocene rocks cropping out in western and central Hawke's Bay. Biofacies defined from field observations are denoted †. Lithofacies are summarised in Table 1. Tt, Tongaporutuan (early Late Miocene); Wo, Opoitian (Early Pliocene); Wm, Mangapanian (Late Pliocene); Wn, Nukumaruan (Early Pleistocene). Refer to Bland (2006) for additional discussion and supporting evidence for interpretations.

Macrofaunal association	Typical macrofauna	Inferred environment of deposition^*	Typical lithofacies^*	Typical age range
Austrovenus (AU)	Very low faunal diversity dominated by Austrovenus stutchburyi. Occasionally Zeacumantus lutuentus, Limperna huttoni and Barytellina crassidens	Estuarine	S7, S8, Z4, Cg5,	Wm–Wc
Paphies (PH)†	Very low faunal diversity, almost exclusively Paphies australis, with rare Ostrea chilensis and Lutraria grandis	Very shallow-water estuaries, semi-enclosed embayments with some current flow	Cg6, MX3	Wn
Fellaster (FE)	Low faunal diversity dominated by Fellaster zelandiae	Beach, very shallow-water nearshore	S3,	Wm–Wn
Zethalia (ZE)	Low faunal diversity with Zethalia spp. dominant. Occasionally contains Lutraria grandis and Dosinia spp.	Very shallow-water beaches, tidal channels	S3, S9, Cg6	Wm–Wn
Maoricrypta-Sigapatella (MA-SG)	Moderate faunal diversity, characterised by the co-dominance of Maoricrypta profunda and Sigapatella novaezelandiae	Nearshore to inner shelf environments on a firm-ground shellhash substrate. Moderate to strong tidal currents	BC4, MX1	Wn
Tawera (TW)	Dominated by Tawera subsulcata. Faunal diversity is moderate to high	Enclosed estuary to inner shelf settings on sandy to shell-gravel substrates with a strong current influence	Cg6, BC3, BC7, MX1, MX3	Wn
Tawera-Sigapatella sub-association (TW-SG)	Moderately high faunal diversity dominated by Tawera subsulcata with common Sigapatella novaezelandiae. Maoricrypta profunda also common	Near-shore to innermost shelf tide-dominated strait, on a coarse shell-gravel substrate	BC4, MX1	Wn
Tawera-Maoricrypta sub-association (TW-MA)	Moderately high faunal diversity dominated by Tawera subsulcata with common Maoricrypta profunda. Sigapatella novaezelandiae also common	Nearshore to innermost shelf in a tide-dominated strait, on a coarse shell-gravel substrate	BC4, MX1	Wn
Tawera-Patro sub-association (TW-PT)	Low to moderate faunal diversity, co-dominance of Tawera subsulcata and Patro undatus	Lower-inner to upper-middle shelf on a semi firm-ground sandy to silty substrate	Z3, Z4	Wn
Dosinia (DO)	Moderate faunal diversity, characterised by Dosinia (Phacosama) subrosea and Dosinia (Austrodosinia) anus. Also common are Rexithaerus spenceri, Tellinota edgari, Peronaea gaimardi and Austromegabalanus decorus	Sandy substrates at shoreface to inner shelf (0–30 m), mostly above fair-weather and storm wave-base	S3, S4, S9	Wm–Wn
Maoricolpus (MC)	Low to moderate faunal diversity, characterised by Maoricolpus roseus	Hard-bottom coarse shell debris substrate in tidal channels within semi-enclosed embayments. More shoreward than the Tawera association	MX3	Wm–Wn
Ostrea-glycymerid (OS-GL)†	Low to moderate faunal diversity, characterised by Ostrea chilensis in association with glycymerid bivalves such as Glycymeris spp. and Tucetona laticostata. May also contain Phialopecten spp. and Mesopeplum convexum	Nearshore to innermost shelf on a firm sandy to gravelly substrate. Strong tidal currents swept fine siliciclastic sediment away from substrate	Cg6, MX3	Wo–Wn
Ostrea-Purpurocardia (OS-PU)†	High faunal diversity characterised by Ostrea chilensis and Purpurocardia purpurata. Taxa typically thick-shelled robust epifaunal and semi-infaunal species such as Lutraria grandis and Alcithoe arabica with some Glycymeris shrimptoni and Tucetona laticostata	Nearshore to innermost shelf on gravelly substrates. Seafloor swept by strong tidal currents	Cg6, MX3	Wn
Eumarcia (EU)†	High faunal diversity characterised by Eumarcia plana. Also may include Paphies australis, Fellaster zelandiae, Mactra discors, Zethalia spp., Bassina spp., Dosinia (Fallertemis) lambata, Glycymeris shrimptoni, Gari lineolata, Scalpomactra scalpellum, Divaricella huttoniana, Myadora waitotarana, Purpurocardia purpurata, and Tawera subsulcata.	Shallow-water nearshore to innermost shelf environment under a regime of strong tidal currents	BC3	Wm–Wn
Tucetona (TU)†	Moderate faunal diversity characterised by robust semi-infaunal and epifaunal bivalves. Dominated by Tucetona laticostata. May include common Ostrea chilensis, Crassostrea ingens, Oxyperis elongata (komakoensis form), Phialopecten spp. and Eucrassatella sp.	Nearshore settings on very coarse sandy to gravelly substrates, probably in tidal channels. Proximal to exposed rocky Torlesse greywacke coastline	Cg3, BC3, MX3	Wo–Wn
Zeacolpus (ZC)†	Typically monospecific, dominated by Zeacolpus spp.	Shallow-water nearshore to inner shelf environments on a sandy to slightly gravelly substrate	S11, Cg6, MX3	Tt
Struthiolaria (Callusaria) (ST)†	Low to moderate faunal diversity, dominated by Struthiolaria (Callusaria) spp., with common Zenatia acinaces and Zeacolpus sp. May also contain Sectipecten grangei and Crepidula radiata.	Nearshore to inner shelf setting on sandy to slightly gravelly substrates. Proximal to rocky Torlesse greywacke coastline	S11, Cg6, MX3	Tt–Wo
Crassostrea (CS)†	Low faunal diversity, dominated by Crassostrea ingens. Other robust epifaunal and semi-infaunal taxa are present including Maoricardium spatiosum, Tucetona laticostata and Phialopecten spp.	High-energy shoreface to nearshore settings on hard-grounds adjacent to a rocky greywacke coastline	Cg7	Wo–Wm
Crassostrea-Phialopecten sub-association (CS-PP)†	Low faunal diversity, characterised by the abundance of Crassostrea ingens and Phialopecten thomsoni. Patro undatus is also common. Barnacle fragments and plates are very common among the bivalves	Nearshore to inner shelf water depths on a gravelly mixed bioclastic-siliciclastic hard-ground	BC2, BC5, MX2	Wm
Neothyris (NE)†	Low faunal diversity, characterised by the abundance of Neothyris aff. obtusa. The association commonly contains Phialopecten spp. and almost always Ostrea chilensis. Barnacle fragments and plates are very common among the bivalves	Firm shell-gravel to sandy firm-ground at lower-inner to middle shelf water depths. Seafloor swept of strong tidal currents	BC2, BC5, MX4	Wm
Atrina (AT)†	Typically monospecific association containing Atrina pectinata zelandica	Inner shelf to upper-middle shelf water depths with a silty sand substrate with a moderately high siliciclastic sediment input	S4, S5, S6, S10, Z3, Z8, Z9	Wm–Wn
Mactra (Maorimactra) (MM)	Low to moderate faunal diversity dominated by Mactra (Maorimactra) spp.	Soft fine sand to silty sand substrates at inner to middle shelf water depths (20–60 m). More open marine than Dosinia (Kereia) association	S4	Wn
Dosinia (Kereia) (DK)†	Low to moderate faunal diversity dominated by Dosinia (Kereia) greyi, with common Atrina pectinata zelandica, Pratulum pulchellum, Ostrea chilensis, Talochlamys gemmulata, Stiracolpus spp., Alcithoe spp., Austrofusus spp. and Pelicaria spp.	Fine silty sand substrates at inner to middle shelf (10–50 m) water depths	S4, S6, Z3, Z9	Wm–Wn
Ostrea (OS)†	Low faunal diversity dominated by Ostrea chilensis. Usually monospecific although may contain Zeacolpus vittatus and Dosina spp.	Silty firm-ground substrate at lower inner- to outer-shelf water depths, probably association with sediment starvation. Often present on top of downlap surfaces	Z2, Z5, Z11	Wm–Wn
Patro (PT)	Low faunal diversity dominated by Patro undatus	Lower-inner to middle shelf water depths on fine sandy silty firm-grounds	S5, S7, Z3	Wm–Wn
Talochlamys (TA)	High faunal diversity, characterised by Talochlamys gemmulata, with common Atrina pectinata zelandica and Pelicaria spp.	Fine-grained silty firm-ground at middle to outer shelf water depths. Firm-ground development may represent periods of sediment starvation	Z8	Wm–Wn
Stiracolpus-Talochlamys sub-association (SC-TA)	Moderate to high faunal diversity characterised by co-dominance of Stiracolpus spp. and Talochlamys gemmulata. Nucula sp. and Neilo sp. are common secondary taxa	Middle to outer shelf water depths (50–150 m) on fine silty substrates	Z3, Z5	Wm–Wn
Notosaria-Talochlamys sub-association (NO-TA)	Moderate faunal diversity characterised by the dominance of Notosaria niagricans	Firm-ground at lower-inner to middle shelf water depths. Firm-ground development may represent periods of sediment starvation	Z2	Wn
Neilo (NI)†	Low faunal diversity characterised by Neilo spp. with common Notocallista multistriata, Calliostoma sp., Talochlamys gemmulata, Pleuromeris sp. and Nuculanids	Middle to outer shelf, fine sandy silt and silty substrates, often with a fine pebble content	Z2, Z5	Wm–Wn
Pratulum (PR)	Very low to moderate faunal diversity characterised by Pratulum pulchellum. May be monospecific, or contain Talochlamys gemmulata, Ostrea chilensis, Dosinia (Kereia) greyi, Zenatia acinaces, Antalis nana, Pelicaria spp. and Austrofusus spp.	Lower-inner to outer shelf water depths on a seafloor characterised by soft incoherent silty sediments	Z2, Z8	Wm–Wn

Figure 4 Schematic illustrations showing the idealised distribution of lithofacies and macrofossil associations in Late Pliocene–Early Pleistocene Mangaheia Group shelf rocks in central and western Hawke's Bay. Lithofacies codes refer to those listed in Table 1. Macrofossil association codes are defined in Table 2.

Figure 5 Simplified palaeogeographic maps for the (A) late Opoitian (c. 4 Ma), (B) mid-Mangapanian (c. 2.8 Ma), (C) base Nukumaruan (2.4 Ma) and (D) late Nukumaruan (c. 1.8 Ma), illustrating the general distribution of macrofaunal associations, water depths and palaeoenvironments as determined from outcropping strata of that age. The base Nukumaruan (C) and late Nukumaruan (D) maps are drawn for late LST-early TST time with the lowstand shoreline near its maximum progradational extent. The modern shoreline is approximated by the dotted black line. Map A: KL, Kairakau Limestone; MGF, Mangatoro Formation; OF, Omahaki Formation; PAF, Pakaututu Formation; TKF, Titiokura Formation; WF, Wairoa Formation. Map B: MU, Makaretu Mudstone; PF, Pohue Formation; PKF, Puketitiri Formation; TM, Taradale Mudstone; TOL, Te Onepu Limestone; TW, Te Waka Formation. Map C: MRF, Mason Ridge Formation; MTF, Matahorua Formation; MU, Makaretu Mudstone; PP, Pakipaki Limestone; SBF, Sentry Box Formation; SI, Scinde Island Formation; TM, Taradale Mudstone. Map D: FR, Flag Range Conglomerate Member; OKF, Okauawa Formation; PNF, undifferentiated Petane Formation; TGL, Tangoio Limestone Member. Lithofacies codes are summarised in Table 1 and biofacies in Table 2 (see also Bland 2006). For detailed descriptions of the lithostratigraphic units refer to Beu (1995) and Bland et al. (2007).

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