ArticlePDF Available

Late Quaternary palaeoceanography of the western Woodlark Basin (Solomon Sea) and Manus Basin (Bismarck Sea), Papua New Guinea, from planktic foraminifera and radiocarbon dating

Authors:

Abstract

Foraminiferal assemblages and radiocarbon dates from three cores collected in the western Woodlark Basin and one from the Manus Basin have provided information on late Quaternary sedimentation rates and characteristics of water masses. In the western Woodlark Basin, where turbidites and slumps are present, sedimentation rates vary from a few tens of cm/1000 year to 140 cm/1000 year, with background rates decreasing eastwards from New Guinea from 7 cm/1000 year to 3.7 cm/1000 year. In the Manus Basin during the past 16,000 years the sedimentation rate was 15.5 cm/1000 year. In the western Woodlark Basin the lysocline has deepened by at least 900 m over the past 23,500 years. It was above 2680 m before 23,500 years ago; at 3145 m about 13,000 years ago and is now at 3500 m. During the past 30,000 years variations in the mean annual temperatures of surface waters in the western Woodlark Basin were about 3 °C, and about 4.5 °C in the Manus Basin. There were cool intervals at 19,500 and 13,000 years ago. A poorly developed early Holocene warm interval 10,000 − 8500 years ago was followed by a cooler interval with a minimum 8000 years ago. The Holocene climatic optimum occurred 5000 years ago with temperatures higher than at present.
... This observed sharp increase in POC at the Holocene boundary is consistent with the TOC content in sediment cores collected from the southeastern Solomon Sea and the Bismarck Sea. This has been hypothesized to reflect a regional feature and might represent a paleoceanographic event in the equatorial western Pacific (Barash and Kuptsov, 1997). According to our modeling efforts, this increase in POC content could be reconstructed by increasing POC flux to the seafloor from 37.5 to 75 μg cm −2 yr −1 at the boundary of Holocene and deglaciation period. ...
... In fact, Burke et al. (1993) speculated that a significant drop in the overall abundance of benthic foraminifera in deep-sea sediments of Ontong Java Plateau (western WPWP) was caused by a marked decrease in the supply of organic matter during the deglaciation period. This apparently regional decrease in the flux of organic carbon at the transition from the deglaciation to early Holocene has been attributed to a decline in surface productivity (Burke et al., 1993;Barash and Kuptsov, 1997). ...
... This suggests that although the content of bulk sedimentary organic carbon declined, the relative contribution of marine organic matter to the bulk sedimentary organic matter increased during the transition from the deglaciation period to early Holocene. This disagrees with the conclusions of Burke et al. (1993) and Barash and Kuptsov (1997) that a decline in primary productivity prevailed from the end of Pleistocene to the early Holocene. In fact, we speculate that the contribution of terrestrial organic matter input has diminished since the deglaciation period (~13 ka) (Fig. 3E). ...
Article
Transient features in the organic carbon content of deep-sea sediment cores resulting from changes in the flux and/or quality of sedimentary organic matter are not uncommon. We examined the geochemical characteristics of sediments retrieved with a gravity corer from the northwestern Solomon Sea (3908m water depth), southern West Pacific Warm Pool (WPWP). δ13C and δ15N of sedimentary organic matter, together with TOC/TN data suggest that the organic material is characterized by a mixture of marine and terrestrial origins with a higher contribution from marine algae. The data were analyzed with an inverse non-steady-state reaction-transport model to examine the variability and magnitude of particulate organic carbon (POC) flux to the seafloor during the transition between the deglaciation period and early Holocene. Measured POC content and porewater NO3−, NH4+, DIC and SO42− concentrations were used to constrain the model. Hindcast results revealed that POC flux decreased from 75 to 37.5 μg cm−2 yr−1 during the deglaciation–early Holocene transition. The rate of POC degradation in the present setting is slightly lower compared to that in the pre-Holocene setting. The synchronous decline in the relative contribution of terrestrial organic matter input and rapid sea level rise during this transition suggest that sea level, rather than surface productivity, is the dominant factor controlling the POC deposition flux in the Solomon Sea. This is conceivable because the sampling site is proximal to high-relief islands with high rainfall, a well-developed submarine canyon system and narrow and steep continental margins. Consequently, we suggest that deep-water basins in proximity to similar high-relief mountainous islands in the tropical Pacific may represent important sinks for terrestrial organic material, especially during sea level lowstands.
... The relatively high sedimentation rate in Manus Basin allows us to broadly distinguish different volcanic events based on the thickness of sediment cover. Sedimentation has been occurring at a rate~15.5 cm/ka in the central Manus Basin over the past 16,000 years (Barash and Kuptsov, 1997). Hrischeva et al. (2007) calculated an even higher sedimentation rate, not corrected for compaction, of between 26.5 to 33 cm/ka for the eastern Manus Basin. ...
Article
This study presents a systematic analysis and interpretation of autonomous underwater vehicle-based microbathymetry combined with remotely operated vehicle (ROV) video recordings, rock analyses and temperature measurements within the PACManus hydrothermal area located on Pual Ridge in the Bismarck Sea of eastern Manus Basin. The data obtained during research cruise Magellan-06 and So-216 provides a framework for understanding the relationship between the volcanism, tectonism and hydrothermal activity. PACManus is a submarine felsic vocanically-hosted hydrothermal area that hosts multiple vent fields located within several hundred meters of one another but with different fluid chemistries, vent temperatures and morphologies. The total area of hydrothermal activity is estimated to be 20,279 m2. The microbathymetry maps combined with the ROV video observations allow for precise high-resolution mapping estimates of the areal extents of hydrothermal activity. We find the distribution of hydrothermal fields in the PACManus area is primarily controlled by volcanic features that include lava domes, thick and massive blocky lava flows, breccias and feeder dykes. Spatial variation in the permeability of local volcanic facies appears to control the distribution of venting within a field. We define a three-stage chronological sequence for the volcanic evolution of the PACManus based on lava flow morphology, sediment cover and lava SiO2 concentration. In Stage-1, sparsely to moderately porphyritic dacite lavas (68 - 69.8 wt. % SiO2) erupted to form domes or cryptodomes. In Stage-2, aphyric lava with slightly lower SiO2 concentrations (67.2 – 67.9 wt. % SiO2) formed jumbled and pillowed lava flows. In the most recent phase Stage-3, massive blocky lavas with 69 to 72.5 wt. % SiO2 were erupted through multiple vents constructing a volcanic ridge identified as the PACManus neovolcanic zone. The transition between these stages may be gradual and related to progressive heating of a silicic magma following a recharge event of hot, mantle-derived melts.
... A significant feature, subject to the constraint of poor recovery, is the total absence in core of foraminiferal hemipelagic sediment layers between apparent flow units. This suggests very rapid construction of Pual Ridge in view of high hemipelagic sedimentation rates in the region (Barash and Kuptsov, 1997, cite a uniform rate of 15.5 cm/k.y. over the past 16,000 yr for the central Manus Basin; rates from 14 C dating of foraminifers in shallow sediment cores at four sites in the eastern Manus Basin average 23 cm/k.y.; J.B. Keene and R.A. Binns, unpubl. ...
Article
Full-text available
In the Ocean Drilling Program's only foray to an active seafloor hy-drothermal system hosted by felsic volcanic rocks at a convergent plate margin, deep penetrations were achieved at two contrasted sites within the PACMANUS field (Manus backarc basin, Papua New Guinea). Just 1.0 km apart, these sites are characterized, respectively, by diffuse low-temperature venting at the seabed (Site 1188, Snowcap site; 1650 meters below sea level [mbsl]) and focused high-temperature venting (Site 1189, Roman Ruins; 1700 mbsl). Shallow holes at a background lo-cation remote from known hydrothermal activity (Site 1190) and at a second high-temperature chimney field (Site 1191, Satanic Mills) failed to drill beyond unaltered felsic lavas which at Sites 1188 and 1189 form an impervious cap (as thick as 35 m) to an underlying, pervasively al-tered lava sequence with occasional volcaniclastic horizons. To the maximum depth drilled (387 meters below seafloor [mbsf]), alteration assemblages are characterized by clay minerals and ubiqui-tous disseminated pyrite. Hydrothermal K-feldspar at Site 1189 differen-tiates it from Site 1188 where, by contrast, several intervals of pyrophyllite-bearing acid sulfate alteration suggest input from mag-matic volatiles. At both deeply penetrated sites the dominant silica phase in alteration assemblages changes downhole from opal-A at the transition from overlying unaltered lava to cristobalite and then to quartz. The boundary between the cristobalite and quartz domains is gradational between 60 and 110 mbsf in Hole 1188A under Snowcap., 2007. Leg 193 synthesis: anatomy of an active felsic-hosted hydrothermal system, eastern Manus Basin, Papua New Guinea.
Article
Two new deep marine occurrences of pumice from Papua New Guinea are located in extensional rift settings rather than island arcs. Peralkaline rhyolite pumice occurs at water depths of 700 to 950 m on the wall of a rift ˜80 km west of the propagating Woodlark seafloor spreading axis, within a submarine extension of the dormant D'Entrecasteaux volcanic province. Outcrops up to 100 m long surveyed by manned submersible possess rind zones with polygonal fracturing and local ropy surfaces, and are interpreted as coherent lava flows with no evidence of explosive fragmentation. In the eastern Manus Basin a dredge haul of rhyodacite pumice with exceptionally high vesicularity, from a possible outcrop at the 2,100 m-deep foot of a major extensional fault scarp, resembles exotic pumice fragments recovered from ooze elsewhere in the basin. Their low-K geochemistry conforms to no likely source among subaerial or submarine volcanic centers in the region. A mafic xenolith within this pumice shows features consistent with derivation of the pumice by fractional crystallization within a lower crustal magma chamber followed by tectonic decompression, vesiculation, and eruption to the deep seafloor. If the presence of outcropping pumice at the fault scarp location is confirmed by future photography or submersible observation, a new style of deep marine pumice occurrence will become established that needs to be taken into consideration when interpreting ancient sequences.
Article
AUV-based microbathymetry combined with ROV video data was used to create the first high-resolution geologic maps of two hydrothermal active areas in the eastern Manus Basin: North Su volcano and PACManus hydrothermal field on Pual Ridge. The data were recorded in 2006 and 2011 during the research cruises Magellan-06 operated by the Woods Hole Oceanographic Institution and BAMBUS (SO-216) operated by MARUM / University Bremen. High accuracy underwater navigation transponder-based and Posidonia systems allowed us to combine video data with bathymetry. The navigation on both cruises was very precise (m-scale) and navigation offsets were less than 10 m. We conducted detailed geologic mapping and sampling to identify the seafloor volcanic and hydrothermal features and created highly detailed maps that provide a comprehensive picture of the seafloor and vent distribution in the eastern Manus Basin. Several different types of dacite lava morphology were mapped, including pillow lava, lobate flows and massive block lava. We have compiled all available information on rock chemistry, fluid and temperature measurements, video data, bathymetry and navigation data into a GIS database. We find that, in contrast to the tectonic control on vent distribution at slow spreading mid-ocean ridges, the pathways of upwelling hydrothermal vent fluids at PACManus are dominated by volcanic features, such as lava domes and thick, massive block lava flows. Vent fields are developed preferentially along the margins of major flow units, probably because the cores of these units are impermeable to fluid flow, while the autobrecciated outer parts of the flows are not. In the North Su area, a comparison of seafloor maps from 2006 and 2011 reveals recent volcanic activity, which has strongly modified the bathymetry and hydrothermal vent distribution on the southern flank of the volcano. An ash cone with multiple small craters on the SW flank of the North-Su volcano that didn't exist in 2006 was mapped in 2011. Also, magmatic degassing was much more vigorous in 2011, with large accumulations of liquid sulfur (from disproportionation of magmatic SO2) as well as extensive bubbling of supercritical and liquid CO2.
Article
Forty-nine genera and 85 diatom species are reported from western Woodlark Basin Late Pleistocene and Holocene bathyal sediments. Although planktic pelagic diatoms predominate throughout, shallow-water benthic and neritic forms, with some brackish and fresh-water forms, are common in the upper (Holocene) part of the section. This implies sediment redeposition by slumps and turbidity currents. The redeposited assemblages are absent from underlying Upper Pleistocene sediments deposited during a cold interval, but reoccur in warmer water (Würm) sediment deeper in the section.
Article
The stratigraphic succession of the western Woodlark Basin is examined in detail relative to ODP Site 1109, where c. 55 m of Pliocene sediment lies anomalously shallow owing to slumping between c. 1.10 and 0.65 Ma in the tectonically active rift basin. Palaeomagnetic reversals and varying percentages of the characteristic microfossils, Globigerinoides fistulosus and discoasters, within the deformed sediment defining the slump indicate that the Pliocene sediment was periodically introduced by a number of slumps rather than being emplaced by a single slump event. Palaeomagnetic and biostratigraphic events in the remainder of the hemipelagic section of Site 1109 to c. 4 Ma appear undisturbed and consistent with those at adjoining sites. Globorotalia truncatulinoides first appeared between 2.65 and 2.71 Ma at these low-latitude sites, which extends the previously reported area of evolution of the species in the southwestern Pacific toward the Equator. Seven of the nine coiling changes in Pulleniatina through time are recognized and dated using sedimentation rates. Along with palaeomagnetic events and micro-fossil species datum levels, these coiling changes can be used to correlate between sites in the area.
Article
In the western Woodlark Basin within the neovolcanic zone sediments form ponds in fissures and between individual pillows and tubes. A continuous thin sediment cover appears only at the base of the neovolcanic zone. Its thickness increases with the distance from the zone. Data on the lithology, mineralogy and chemistry of sediment cores from the spreading centre in the western Woodlark Basin and adjacent areas show that these calcareous sediments (avg. 44.1 % CaCO3) contain significant amounts of terrigenous, arc volcanic, hyaloclastic and hydrothermal material, the latter constituting up to 15% of the non-carbonate fraction. Two types of sedimentary sequences occur in the studied area. Those of the first type were formed by particle-by-particle sedimentation; horizons of redeposited sediments occur in sequences of the second type. Redeposition of sediments is widespread and is tentatively correlated with cycles of volcanic activity at swells along the spreading centre. These alternate with hydrothermal cycles, which were determined by the presence of hydrothermal matter in sediments. Radiocarbon dating of sediments showed that both cycles are of similar duration, of the order of 10,000 years. They are not synchronous along the spreading axis, each swell having a specific evolution. Based on these determinations we can say that within the studied spreading centre only the Franklin Seamount swell is prospective for contemporary hydrothermal activity.
Article
Full-text available
The oxygen isotope records of G. sacculifer and Pulleniatina in the uppermost three cores at Ocean Drilling Program Hole 805C span the last 1.6 m.y., an estimate based on Fourier stratigraphy. The last 700,000 yr are dominated by both eccentricity- and obliquity-related orbital fluctuations. The range of variation of δ 18 θ values is about 1.5‰, of which ca. 75% may be assigned to global ice-volume effect. The remainder of the range is shared by the effects of surface temperature variation, thermocline depth change (in the case of Pulleniatina, especially), and differential dissolution. Before 1 Ma, obliquity-related fluctuations dominate. The transition between obliquity- and eccentricity-dominated time occurs between ca. 1 and 0.7 Ma. It is marked by irregularitie s in phase relationships, the source of which is not clear. The age of the Brunhes/Matuyama boundary is determined as 794,000 yr by obliquity counting. However, an age of 830,000 yr also is compatible with the counts of both eccentricity and obliquity cycles. In the first case, Stage 19 (which contains the boundary) is coincident with the crest of the 19th obliquity cycle, setting the first crest downcore equal to zero, and counting backward (ol9). In the second, Stage 19 coincides with o20. No evidence was found for fluctuations related to precession (23 and 19 k.y.) rising above the noise level, using plain Fourier expansion on the age model of the entire series. Detailed stratigraphic comparison with the Quaternary record of Hole 806B allows the recognition of major dissolution events (which increase the difference in δ 18 θ values of G. sacculifer at the two sites). These occur at Stages 11-13, 16-17, and near 1.5 Ma (below o33).
Article
The development of reliable paleoclimatic maps at a global scale requires data at the following three levels of analysis: (1) well-recorded observations of evenly positioned, well-dated geological evidence (Level I), (2) paleoclimatic estimates derived from this evidence by well-defined quantitative repeatable methods (Level II), and (3) maps synthesizing the estimates from several independent sources of geological evidence (Level III). Our paper describes much of the currently available paleoclimatic data from unglaciated terrestrial areas at ca. 18,000 yr B.P. and illustrates the quantity and quality of the data at both the Level I and the Level II stages of analysis. Although the scarcity of well-dated evidence for this time period precluded any major Level III syntheses of the information, comparisons were drawn where possible between the geological evidence and the climatic conditions simulated by general-circulation model experiments of and and Manabe and Hahn (1977). Of the more than 320 sites with data from 18,000 yr B.P., only 65 are well-dated with bracketing dates within the interval of 23,000 to 13,000 yr B.P., whereas about 100 are undated or poorly dated. We concentrated our survey on palynological and paleobotanical evidence and also thoroughly reviewed the evidence for water levels in lakes at 18,000 yr B.P. In areas with few of these sources of evidence, data on former snowlines, periglacial features, and eolian deposits were included, but the survey of these data is far from complete. Maps of the assembled data reveal the consistency of the paleoclimatic estimates in “data-rich” areas and also show which areas required additional information. The maps show that conditions were colder than present at 18,000 yr B.P. for all sites with temperature estimates. Estimated temperature depressions varied from ca. 1° to 12°C or more, depending on the location of the sample, the type of geological evidence, and the method of temperature estimation. Interpreted hydrological conditions were more variable spatially than the temperature estimates. The southwestern U.S. was moister than present, whereas the southeast may have been drier. Europe and the northern Mediterranean across to Afghanistan were drier than present, but northwest Africa was wetter. Australia was mainly drier than present, but several sites there as well as in Africa show significant climatic changes between 21,000 and 16,000 yr B.P. This latter evidence suggests that considerable variability may have occurred during the several thousand-year period centered on 18,000 yr B.P. Accurate time control is therefore required for the geological data used to study the climate dynamics of 18,000 yr ago. Large portions of South America and Asia as well as significant portions of the other continents lack the data base, or at least the well-dated base, required to define the 18,000 yr B.P. climate. In the few areas where comparisons were made with the Ice Age climates simulated by general-circulation models, general agreement existed between the geological evidence and the model simulations. Many critical comparisons were thwarted, however, by the lack of model simulations for all seasons at 18,000 yr B.P. Difficulty in validating precipitation anomalies in the tropics also arose because surface-albedo values, which are a vital input to the general circulation models, are estimated from the same evidence that is used to validate the results of the models.
The distribution of planktonic Foraminifera in South Pacific sediments reflects the environments of production in surface waters and those of preservation on the ocean floor. Cluster analysis shows that distribution patterns have well-defined boundaries that correspond to the Subtropical Convergence, the Antarctic Polar Front, and the Peru-Chile Current in surface waters, and to the lysocline (level below which solution greatly increases) at depth. The interrelation of clusters is examined by temperature-solution rank analysis which shows how the great diversity of Foraminifera in tropical regions leads to a proliferation of clusters and how some clusters are derived from others by partial dissolution. The compensation depth, where Foraminifera disappear, is conceptually different from the lysocline which separates well-preserved from noticeably dissolved assemblages, and the two levels are not parallel. The variable thickness of the zone of partial dissolution between these levels suggests that the supply of calcareous shells and their dissolution tend to vary together, but in a non-linear fashion. Notes on selected species, including coiling-direction distributions, are appended.