Q-mode Factor Analysis Research Articles

Multivariate statistical “unmixing” of Indian and Pacific Ocean sediment provenance

AbstractThe geochemistry of marine sediment is a massive archive of (paleo)oceanographic information. Accessing that information requires “unmixing” the various influences on marine sediment geochemistry to understand individual sources and marine geochemical processes. Q‐mode factor analysis (QFA) and independent component analysis (ICA) are multivariate statistical techniques that have successfully been applied to large datasets of marine sediment element concentrations to identify the number and composition of marine sediment sources or end‐members. In this study, we apply both techniques to two datasets of marine sediment geochemistry, compare the output, and discuss the advantages of each approach. In both datasets, ICA identified a mixing trend between carbonates and dust, whereas QFA represented the end‐members as two separate factors. In the Pacific and Indian Oceans dataset, both techniques produced three factors or independent components involving rare earth elements, but two of the QFA factors explained a small, almost negligible, amount of the variability of the dataset. Also, QFA identified more aluminosilicate end‐members (dust or volcanic ash) than ICA. In the Indian Ocean Sites 738 and 752 dataset, ICA identified two processes affecting Sr and Ba concentrations as separate independent components, while QFA created a factor representing the covariation of Sr and Ba over intervals of the site's paleoceanographic history. The results of this study exemplify that QFA identifies covariances and finds discrete end‐members contributing to the bulk mass of sediment. ICA works best with non‐Gaussian element distributions and finds geochemical signals and mixing trends that constitute the characteristic structure of the multielemental data.

Radiolarian assemblages related to the ocean–ice interaction around the East Antarctic coast

Abstract. The Southern Ocean plays a central role in Earth's climate, ecology, and biogeochemical cycles. Therefore, understanding long-term changes in Southern Ocean water masses in the geologic past is essential for assessing the role of the Southern Ocean in the climate system. Radiolarian fossils are a useful tool to reconstruct the water masses of the Southern Ocean. However, the radiolarian assemblages in the high latitudes of the Southern Ocean (south of the polar front (PF)) are still poorly understood. In this paper, we report the radiolarian assemblages in surface marine sediment and plankton tow samples collected from the high latitudes south of the PF. In the surface sediments, four factors (named F1–F4) of the radiolarian assemblages were identified using Q-mode factor analysis, which are related to different water masses and hydrological conditions. F1 is related to the surface waters south of the southern boundary (SB) of the Antarctic Circumpolar Current (ACC), which are cooled by melting sea ice and ice sheets. F2 is associated with water masses north of the SB. A comparison with the vertical distribution of the radiolarian assemblages in plankton tow samples indicates that characteristic species are associated with the Circumpolar Deep Water (CDW) and surface waters north of the SB. F3 is associated with modified Circumpolar Deep Water (mCDW). The radiolarian assemblage of F4 does not seem specifically related to any of the water mass here analyzed. However, the species in this assemblage are typically dwells within ice shelf and/or sea ice edge environments. Radiolarian assemblages here identified and associated with water masses, and ice edge environments are useful to reconstruct the environment south of the PF in the geologic past.

New Southern Ocean transfer function for subsurface temperature prediction using radiolarian assemblages

Radiolarians are microzooplankton that produce siliceous shells that preserve well in sediments and allow for paleo-reconstructions. Previous studies have used them for sea surface temperature (SST) reconstructions. However, radiolarians peak in abundances between 100 and 400 m in the Southern Ocean (SO), suggesting that their assemblages are more representative of subsurface conditions. Here, we aim to develop a SO-wide transfer function (TF) for subsurface temperature reconstructions (subST) using the Southern Ocean RAdiolarian Dataset (SORAD), a compilation of data for about 240 radiolarian taxa in 228 surface sediment samples from the SO. This exhaustive dataset has been simplified using common TF criteria to minimize noise and optimize SORAD for subST prediction. Ordination tests and Q-mode Factor Analyses (QFA) were applied to the resulting training dataset, which includes 212 samples and 75 taxa (SORAD212_75). The results suggest that, out of six environmental variables, radiolarian assemblages in SORAD are mainly driven by summer temperatures at 200 m and that the first five factors of the QFA explained over 75% of SORAD212_75 variance. We applied common TF methods, IKM, MAT and Weighted-MAT (WMAT), to two data transformations (relative abundances of species and log-transformed). The six models of modern temperature predictions all show excellent performance over the −2 to 18 °C interval. To compare with previously published results generated with the same method, IKM% was applied to radiolarian census data of three cores from the Atlantic, Indian and Pacific sectors of the SO, thus calculating new subST reconstructions and testing the new TF performance.

Changes in morphological parameters of the radiolarian Lampterium lineage from the middle Eocene in the tropical Pacific

Radiolarians are one of important proxies for the biostratigraphic and paleoceanographic studies, but little is known about their morphometric variation over time. Here, we reconstructed morphological changes of the Lampterium lineage during the middle Eocene using deep-sea sediments at IODP Expedition 320 Site U1331 in the tropical Pacific. A total of 1236 specimens of the Lampterium lineage in 33 sedimentary samples were observed by light microscopy, and 15 parameters were measured for each specimen. Q-mode factor analysis of 13 parameters evidenced gradual morphologic changes began during the interval from 43.7 to 43.3 Ma, and there were two major events: the first between 41.4 and 40.9 Ma and the second at 39.9 Ma. Basically, the total length and abdominal pores increased in size, the abdomen changed from an inflated cylindrical to subconical shape, and the number of specimens with three shovel-shaped feet decreased. The percentage of each species within the Lampterium lineage suggest it is not easy to determine the two evolutionary transitions that are, however, used to define the bases of tropical radiolarian zones RP15 and RP16.

Benthic foraminiferal response to orbital-scale variability in primary productivity off the Portuguese margin over the last 1.3 Myr

Detailed analyses of benthic foraminiferal fauna and planktonic foraminiferal stable carbon isotopes at IODP Site U1391 were performed to reconstruct orbital-scale variability in primary productivity off the Portuguese margin over the last 1.3 Myr. Q-mode factor analysis of benthic foraminiferal census data from the >250 μm fraction reveals four assemblages, which is mainly controlled by the organic matter flux to the seafloor deriving from surface water productivity. The Sphaeroidina bulloides assemblage accounts for nearly half of the total variance, consisting of S. bulloides, the agglutinated taxa and Lenticulina as major components and Cibicidoides robertsonianus, Planulina ariminensis and Uvigerina peregrina parva as subsidiary species. Cibicidoides wuellerstorfi and Bulimina mexicana are important accessory species of the Cibicidoides pachyderma-dominated assemblage. The miliolids assemblage is dominated by miliolids and B. mexicana with Uvigerina mediterranea as the important associated species. The Praeglobobulimina ovata assemblage is represented by P. ovata along with Globobulimina affinis, Melonis pompiloides, Melonis barleeanum and U. peregrina parva as important accessory species. High productivity often occurs during the interglacial stages and is characterized by the S. bulloides assemblage with subsidiary P. ovata assemblage, while low productivity often occurs during the glacial stages and is marked by the miliolids assemblage and the C. pachyderma assemblage. In addition to the distinct glacial/interglacial variations, there is a long-term decreasing trend in primary productivity recorded by benthic foraminifera, which is supported by a broadly increasing trend in the sediment redness (a*). Continuous wavelet analysis of high productivity-related Factor 1 loading (the S. bulloides assemblage) suggests that variations in primary productivity have a middle Pleistocene transition (MPT)-related shift in cyclicity from the ~41-kyr dominant cycle prior to the MPT to the ~100-kyr dominant cycle after the MPT. Cross-spectral analyses between the Factor 1 loading record and δ18O of Globigerina bulloides reveal the control of global ice volume changes on primary productivity. The high coherency between the Factor 1 loading record and δ13C of G. bulloides on the glacial/interglacial timescale suggests that primary productivity off the Portuguese margin may be largely affected by nutrient availability which was related to the Iberian surface hydrographic changes associated with changes in global ice volume.

Sources and Metal Pollution of Sediments from a Coastal Area of the Central Western Adriatic Sea (Southern Marche Region, Italy)

Sediments represent a critical compartment of marine coastal ecosystems due to the toxic and long-lasting effects of the contaminants buried therein. Here, we investigated the properties of surficial sediments in front of the Southern Marche Region coast (Central Adriatic Sea, Italy). The grain size of the surficial sediments was determined by X-ray sedigraphy. TN and OC contents were determined by elemental analysis. The concentrations of Al, Fe, Mg, K, S, Ca, Ti, P, Na, Mn, Mg, Li, As, Ba, Ga, Pb, Sr, and Zn were determined by ICP-OES to evaluate their spatial patterns and temporal trends. A Q-mode Factor Analyses was applied and resulted in the identification of three compositional facies (Padanic, Coastal, and Residual) characterized by common biogeochemical, mineralogical, sedimentological properties, transport pathway, and source. Some pollution indicators, such as the enrichment factor, the geoaccumulation index, and the pollution load index were calculated to assess the deviation from the natural background levels. The results showed a pollution by As and Ba due to the human activities in the 20th century. Furthermore, a general decreasing of Al, Ti, P, Co, Cr, Cu, Ga, Ni, Pb, Sc, V, and Y concentrations from the background levels suggested a change in the sedimentation processes during the last decades.

A factor analysis approach to modelling the early diversification of terrestrial vegetation

Data from a new comprehensive macrofossil-based compilation of early plant genera are analyzed via a Q-mode factor analysis. This compilation ranges from the Silurian to the earliest Carboniferous and illustrates the key vegetation changes that took place during the configuration of early terrestrial ecosystems. Results reveal that four factors can be used to explain more than 90% of the variance in the data. These factors are interpreted as the major phases of the early land plant evolution: a first Eotracheophytic flora (Silurian-Lochkovian) dominated by basal eutracheophytes and rhyniophytoids, an early Eophytic Flora (Early Devonian) dominated by zosterophylls, a transitional late Eophytic Flora (Middle Devonian-earliest Carboniferous) dominated by lycopsids and cladoxylopsids, and finally, the earliest phase of the Palaeophytic Flora (Late Devonian-earliest Carboniferous) dominated by the first seed plants. These floras present different but complementary diversity patterns, which help us to understand the overall trajectory of changes in plant diversity. Results further show how the maximum peaks of diversity appear linked to the rise of each new flora but, interestingly, these diversifications are not associated with any exponential declines of the previously dominant one. This new four-phase diversification model reflects the early steps of Earth's greening.

Multivariate analysis of protolytic and tautomeric equilibria of Erythrosine B and its ester derivatives in ionic and non-ionic micelles

Erythrosine B (ERY) is a xanthene dye that has been widely used in recent years as a photoactive drug for Photodynamic Therapy. However, application of ERY and its derivatives as photosensitizer drugs depend not only on their singlet oxygen quantum yield, but also on their hydrophobicity, and photoactive protolytic and tautomeric species. In this work, the objective was to evaluate the acid-base equilibria of ERY and its derivatives: erythrosine methyl ester (ERYMET); erythrosine butyl ester (ERYBUT) and erythrosine decyl ester (ERYDEC), in biomimetic media (micelles of SDS and CTAB) as well as in some drug delivery systems of triblock copolymer Poloxamer (P-123 and F-127). All protolytic chemical equilibria were studied by employing chemometric multivariate analysis based on the Imbrie's Q-Mode Factor Analysis and k-Matrix methods. Tautomeric equilibria were evaluated taking into account of possible chemical structures and electronic spectroscopic approximations. Results from ester derivatives presenting only one protolytic equilibrium (at the phenolate group) and two possible tautomers, allow us to determine that protolytic equilibria follow the sequence pKaCOOH < pKaOH in SDS media for ERY by structure comparison. On the other hand, CTAB and polaxamers inverted the acidity of ERY protolytic groups (pKaOH < pKaCOOH) due to changes in the tautomeric equilibrium due to a lactone formation for the dyes neutral protolytic species inside the micelles. Chemometric approaches provided detailed analyses of protolytic/tautomeric equilibria of ERY. Through this, we achieved a deeper understanding of how ERY and its derivatives are affected by microenvironments in biomimetic and drug delivery systems.

Benthic foraminifera and its response to heavy metal pollution: A case study from Liaodong Bay, China

Benthic foraminifera can be used as an environmental bioindicator, especially in the polluted environment where their sensitivity to pollutants may be expressed by a modification in the assemblage. Based on the quantitative and qualitative analysis of 189 surface sediment samples in Liaodong Bay, 76 benthic foraminifera species which belong to 40 genera were recognized. Q-mode factor analysis was made for the 32 benthic foraminifera species, and three assemblages are recognized: Ammonia aomoriensis- Cribroelphidium magellanicum- Protelphidium tuberculatum; Textularia foliacea- Polskiammina asiatica; and Rotalidium annectens- Buccella frigida. To study the effects of heavy metal elements on benthic foraminifera fauna, seven heavy metals elements have been analyzed in all the surface sediment samples, the results show that the heavy metal elements in Liaodong Bay are mainly distributed in Jinzhou Port, and that the overall characteristics are high in northwest and low in southeast. The distribution of foraminifera and heavy metals elements reveals that there is a significant correlation between them. Cribroelphidium magellanicum and Protelphidium tuberculatum have maintained a high level in heavy metal enrichment areas, and may be used as an indicator of heavy metal contamination along the coast of Liaodong Bay.

Paleoceanographic changes in the East China Sea during the last ~400 kyr reconstructed using planktic foraminifera

Abstract East China Sea (ECS) is greatly influenced by East Asian Summer Monsoon (EASM), precipitation discharge and differential inflow of the warm and saline Kuroshio Current (KC). Any change in surface water conditions either due to variations in ocean currents or discharge from terrestrial rivers have pronounced effects on the population abundance of planktic foraminifera; therefore, planktic foraminifera happen to be a valuable proxy to decipher paleoceanographic changes in the ECS. To understand the influence of KC and EASM at ECS, paleoceanographic changes are reconstructed for the last 400 kyr using planktic foraminiferal population abundances and Mg/Ca ratio derived Sea Surface Temperature (SST) from IODP site U1429. Nine different species/species associations of planktic foraminifera are found to be significant at this site. Q-mode factor analysis of these abundant species helped to retain four factors explaining ~91% of the data variance suggesting four different conditions prevailing at ECS over the last 400 kyr. The species association of factor 1 reflects cold surface water conditions in the ECS, factor 2 suggests the influence of the coastal water, factor 3 can be linked with the upwelling of lower thermocline water, and factor 4 is strongly associated with the strength of the KC. This study suggests that KC and EASM were stronger during the interglacial periods. The proxy that responds to KC strength (Globogerinoides ruber) and calculated Mg/Ca SST shows the presence of 23 kyr precession and 100 kyr eccentricity cycles modulated by the differential inflow of KC due to global and local factors. The comparison of SST of the western Pacific with SST of the ECS shows that KC actively transports heat to ECS from the equatorial western Pacific warm pool.

Platinum enrichment and phase associations in marine ferromanganese crusts and nodules based on a multi-method approach

Marine ferromanganese crusts and nodules host high concentrations of many economically interesting metals such as platinum (Pt), with Pt concentrations in the range of 44 to 3207 ppb in 182 analyzed samples from various locations in the global ocean. Different mechanisms have been proposed to explain this strong enrichment in the MnFe oxide phases compared to seawater, including reduction of seawater Pt(II) to Pt(0) or oxidation to Pt(IV) and surface adsorption on the Fe-oxyhydroxide or Mn-oxide phases. To shed more light on the process of Pt enrichment in nodules and crusts, we applied a multi-method approach including bulk analyses, statistics (correlations and Q-mode factor analyses), sequential leaching, sorption experiments, and XANES and EXAFS measurements. Our analyses lend new support to the heterogeneous oxidation/sorption mechanism advanced by Maeno et al. (2016) to explain the initial Pt(II) enrichment on FeMn crusts, with Pt oxidation only taking place on the Mn-oxide phase but not on the Fe-oxyhydroxide phase of crusts. Nodules show lower concentrations and a lesser association of Pt with the Mn phase as the latter is partly of diagenetic origin while the origin of Pt is hydrogenetic. Our results also indicate that sorption of Pt2+(aq) to FeO(OH) is possible if Pt2+(aq) exists under conditions typical of nodule and crust growth in the oceans. Platinum concentrations are consistently highest in phosphatized FeMn crusts where they appear to be related to the occurrence of a 10 Å manganate, so they are likely to be the best exploration target for Pt globally in marine FeMn crusts. However, further work is needed to understand the geochemical reactions that dominate mass transfer of Pt under conditions under which crusts are phosphatized and to identify the exact mineral type which hosts the Pt enrichment.The complex Pt geochemistry in marine FeMn crusts and nodules due to the different phase associations and enrichment processes on the different carrier phases make a straightforward interpretation of Pt data in specific samples difficult. Our findings suggest that only spatially resolved, species-specific methods available via synchrotron-based X-ray and modern electron-probe micro-analyzers (in development) could provide the combination of spatial resolution and species-specificity to determine which of several proposed mechanisms are actually responsible for Pt enrichment in FeMn crusts.

The radiolarian fauna during the Younger Dryas–Holocene transition in Andfjorden, northern Norway

We report on the changing radiolarian faunas from the Younger Dryas (ca.12.9 calibrated thousands of years BP [cal. Ky BP]) and into the Holocene (ca. 10.3 cal. Ky BP) in the core JM99-1200 from Andfjorden, northern Norway. Temperature reconstructions using both the Q-mode factor analysis and modern analogue technique methods show stable, cold temperatures below ca. 410 cm core depth, followed by abrupt warming into a relatively stable Holocene temperature regime. Age-depth modelling with three different methods gives an age of ca. 11.9–12.0 cal. Ky BP at this core depth, clearly older than the Younger Dryas–Holocene transition at ca. 11.65 cal. Ky BP according to ice core chronology. Considering that the age models may be insufficiently informed in an interval without radiometric dates, it is possible that the base of the Holocene is indeed at 410 cm, as indicated by the radiolarian and other core data. Such a change in the chronology would have implications for previously published work on the JM99-1200 core. Alternatively, the abrupt warming in Andfjorden predated the Younger Dryas–Holocene transition by a few hundred years. A distinct cold pulse at ca. 315–335 cm, or 11.4–11.5 cal. Ky BP is interpreted as the Preboreal Oscillation. The Preboreal Oscillation has not previously been detected in temperature curves based on planktic foraminifera in the same core, indicating that Radiolaria may be a more sensitive temperature indicator in this region.

Aeolian delivery to Ulleung Basin, Korea (Japan Sea), during development of the East Asian Monsoon through the last 12 Ma

AbstractWe reconstruct the provenance of aluminosilicate sediment deposited in Ulleung Basin, Japan Sea, over the last 12 Ma at Site U1430 drilled during Integrated Ocean Drilling Program Expedition 346. Using multivariate partitioning techniques (Q-mode factor analysis, multiple linear regressions) applied to the major, trace and rare earth element composition of the bulk sediment, we identify and quantify four aluminosilicate components (Taklimakan, Gobi, Chinese Loess and Korean Peninsula), and model their mass accumulation rates. Each of these end-members, or materials from these regions, were present in the top-performing models in all tests. Material from the Taklimakan Desert (50–60 % of aluminosilicate contribution) is the most abundant end-member through time, while Chinese Loess and Gobi Desert components increase in contribution and flux in the Plio-Pleistocene. A Korean Peninsula component is lowest in abundance when present, and its occurrence reflects the opening of the Tsushima Strait at c. 3 Ma. Variation in dust source regions appears to track step-wise Asian aridification influenced by Cenozoic global cooling and periods of uplift of the Tibetan Plateau. During early stages of the evolution of the East Asian Monsoon, the Taklimakan Desert was the major source of dust to the Pacific. Continued uplift of the Tibetan Plateau may have influenced the increase in aeolian supply from the Gobi Desert and Chinese Loess Plateau into the Pleistocene. Consistent with existing records from the Pacific Ocean, these observations of aeolian fluxes provide more detail and specificity regarding the evolution of different Asian source regions through the latest Cenozoic.

Clustering of groundwaters by Q-mode factor analysis according to their hydrogeochemical origin: A case study of the Cariri Valley (Northern Brazil) wells

Factor analysis was applied to 56 groundwater samples collected from wells located in the Araripe Sedimentary Basin, in the north-east of Brazil. The parameters are a set of 9 physicochemical, chemical, and isotope data, constituted by electrical conductivity (EC), ionic concentrations of Ca2+, Mg2+, Na+, K+, Cl-, SO42-, alkalinity and δ18O0/00. In R-mode factor analysis, the first 3 factors explain 62% of the variance, their loadings allowing the interpretation of hydrogeochemical processes that take place in the area. Q-mode factor analysis on the 56 water samples decreases space dimensionality to 6, explaining 93% of the total database information. With the aid of a scalar and angular measurement method, objects were clustered, resulting in 11 groups classified according to their inherent characteristics, related to their hydrogeological origin.

Evolution of the Southern Yellow Sea Cold Water Mass during the last 7 kyr from benthic foraminiferal evidence

The Southern Yellow Sea Cold Water Mass (YSCWM) is closely related to the modern circulation system of the east China shelf seas, which has significantly influenced regional marine environmental changes. The study of the Holocene evolution of the YSCWM will greatly improve our understanding of the mechanisms of regional environmental change. Benthic foraminifera are sensitive to bottom water environmental changes and can serve as useful indicators in bottom water environmental reconstruction. In this study, benthic foraminifera were analyzed in core N02 from the northwestern margin of the southern Yellow Sea Mud to decipher the phase evolution of the YSCWM during the last 7 kyr. Benthic foraminifera census counts and Q-mode factor analysis indicate that the Holocene sedimentary environment can be divided into three stages: From 6.9–5.0 ka, the fauna was dominated by Ammonia ketienziensis, indicating that the YSCWM was at its strongest during the last 7 kyr, while the Yellow Sea Coastal Current (YSCC) had a weak influence on the bottom water of the study area. From 5.0–2.9 ka, the relative abundance of Hanzawaia nipponica remarkably increased while the abundance of A. ketienziensis decreased significantly, reflecting that the strength of the YSCWM was relatively weak and the range of the YSCWM might have contracted. The influence of the YSCC on the bottom water might have slightly increased, although its influence was still weak during this time. A notable increase in low-temperature and low-salinity species, such as Protelphidium tuberculatum and Buccella spp. has occurred since 2.9 ka, indicating that the YSCC has had a strong influence on bottom water during this period, while the strength of the YSCWM has been at its weakest during the last 7 kyr. Generally, the influence of the YSCWM and the YSCC on the bottom water properties of the study area show an obvious seesaw pattern, with one’s influence increasing while the other’s influence decreases and vice versa. The fluctuations in the strength of YSCWM during the Holocene may be caused by the different effect allocations of regional climatic factors (i.e. El Nino Southern Oscillation, East Asian Winter Monsoon, summer insolation in the northern hemisphere, etc.) acting on the circulation system during different periods.

Statistical analysis as a tool for assisting geochemical interpretation of the Upper Triassic Yanchang Formation, Ordos Basin, Central China

The Yanchang Formation in the Ordos Basin is the most important petroleum play not only for conventional oil and gas accumulations, but also for newly emerging shale oil and tight gas resources. The molecular characterization of the basinwide source rocks predicts three groups of generative petroleum types: Paraffinic High Wax Oil, mixed base (Paraffinic-Naphthenic-Aromatic) Low Wax Oil, and Gas and Condensate. Supplementary to previous work, 68 samples including the crude oils, source bitumens and reservoir extracts from the Yanchang petroleum play are analyzed. The distribution of two terpane classes (eight tricyclic terpanes and eight pentacyclic terpanes) are determined with subsequent simultaneous RQ-mode factor analysis for a composite data set of these samples alongside 216 published crude oils worldwide with known facies descriptions. Thermal maturity has been evaluated as a consistent distribution at first using a combined method of a maturity-related biomarker [Ts / (Ts+Tm)] and aromatic parameters (Methyldibenzothiophene Ratios) to alleviate the maturity differences effect when discussing geochemical characterization. The R-mode factor analysis consists of the first two factors that are describing 45 present of the cumulative total variance in the data set, and presents a sample grouping pattern in Q-mode factor analysis which is determined by different contributions of terpane associations, i.e., the tricyclic C21 coupled with pentacyclic C26, C27, C28 and C30, in the same factor space. Three terpane associations, the C26 and C28 terpanes, the C21 and C30 terpanes and the C27 pentacyclic terpenes, are respectively responsible for discriminating crude oil, reservoir extracts and source bitumens in RQ-mode factor analysis. Molecular compositions further address more detailed interrelationships among three sample groups that crude oils and reservoir extracts are sharing close genetic relationships both in depositional environment typing and C27-C28-C29 sterane distribution. Samples from source rocks vary much significantly. A mixing process which occurs after oils has been expelled from host source rocks into carrier units during accumulation. In addition, the migration-contamination of C29 sterols when oils are cross through the Chang 7–2 unit along migration pathways might also explain this lack of correlation between source rocks and oil-reservoir system.

Taxonomy of Individual Variations in Aesthetic Responses to Fractal Patterns.

In two experiments, we investigate group and individual preferences in a range of different types of patterns with varying fractal-like scaling characteristics. In Experiment 1, we used 1/f filtered grayscale images as well as their thresholded (black and white) and edges only counterparts. Separate groups of observers viewed different types of images varying in slope of their amplitude spectra. Although with each image type, the groups exhibited the “universal” pattern of preference for intermediate amplitude spectrum slopes, we identified 4 distinct sub-groups in each case. Sub-group 1 exhibited a typical peak preference for intermediate amplitude spectrum slopes (“intermediate”; approx. 50%); sub-group 2 exhibited a linear increase in preference with increasing amplitude spectrum slope (“smooth”; approx. 20%), while sub-group 3 exhibited a linear decrease in preference as a function of the amplitude spectrum slope (“sharp”; approx. 20%). Sub-group 4 revealed no significant preference (“other”; approx. 10%). In Experiment 2, we extended the range of different image types and investigated preferences within the same observers. We replicate the results of our first experiment and show that individual participants exhibit stable patterns of preference across a wide range of image types. In both experiments, Q-mode factor analysis identified two principal factors that were able to explain more than 80% of interindividual variations in preference across all types of images, suggesting a highly similar dimensional structure of interindividual variations in preference for fractal-like scaling characteristics.

Controls on ferromanganese crust composition and reconnaissance resource potential, Ninetyeast Ridge, Indian Ocean

A reconnaissance survey of Fe–Mn crusts from the 5000km long (~31°S to 10°N) Ninetyeast Ridge (NER) in the Indian Ocean shows their widespread occurrence along the ridge as well as with water depth on the ridge flanks. The crusts are hydrogenetic based in growth rates and discrimination plots. Twenty samples from 12 crusts from 9 locations along the ridge were analyzed for chemical and mineralogical compositions, growth rates, and statistical relationships (Q-mode factor analysis, correlation coefficients) were calculated. The crusts collected are relatively thin (maximum 40mm), and those analyzed varied from 4mm to 32mm. However, crusts as thick as 80mm can be expected to occur based on the age of rocks that comprise the NER and the growth rates calculated here. Growth rates of the crusts increase to the north along the NER and with water depth. The increase to the north resulted from an increased supply of Mn from the oxygen minimum zone (OMZ) to depths below the OMZ combined with an increased supply of Fe at depth from the dissolution of biogenic carbonate and from deep-sourced hydrothermal Fe. These increased supplies of Fe increased growth rates of the deeper-water crusts along the entire NER. Because of the huge terrigenous (rivers, eolian, pyroclastic) and hydrothermal (three spreading centers) inputs to the Indian Ocean, and the history of primary productivity, Fe–Mn crust compositions vary from those analyzed from open-ocean locations in the Pacific.The sources of detrital material in the crusts change along the NER and reflect, from north to south, the decreasing influence of the Ganga River system and volcanic arcs located to the east, with increasing influence of sediment derived from Australia to the south. In addition, weathering of NER basalt likely contributed to the aluminosilicate fraction of the crusts. The southernmost sample has a relatively large detrital component compared to other southern NER crust samples, which was probably derived predominantly from weathering of local volcanic outcrops.Fe–Mn crusts from a dredge haul at 3412m water depth, 2°S latitude, are pervasively phosphatized along with the substrate rocks (site D7). Phosphatization took place through replacement of carbonate, preferential replacement of Fe oxyhydroxide relative to Mn oxide in the crusts, preferential replacement of silica-rich phases relative to Al-rich phases in the crusts, and precipitation of carbonate fluorapatite in pore space. The preferentially replaced silica may have been Si adsorbed on the Fe oxyhydroxide. The enrichment of Ni, Zn, and Cu in the phosphatized crust reflects preferential adsorption into the tunnel structure of todorokite. The rare earth element plus yttrium (REY) patterns indicate a lower oxidation potential during phosphatization of the NER crusts compared to Pacific phosphatized crusts. NER phosphatization occurred in a deeper-water environment than typical for phosphatization of Pacific crusts, occurred post-middle Miocene, a younger age than phosphatization the Pacific crusts, and had in part a different set of chemical changes produced by the phosphatization than did the Pacific crusts.The southern third of NER has Fe–Mn crusts with the highest Co (0.91%), Ni (0.43%), ΣREY (0.33%), Cu (0.22%), Te (146ppm), Pt (1.5ppm), Ru (52ppb), and Rh (99ppb) contents. These are among the highest Pt, Ru, and Rh concentrations measured in marine Fe–Mn deposits. Because of these high metal concentrations, exploration is warranted for the southern sector of the NER, especially at shallower-water sites where the platinum group elements (PGE) and Co are likely to be even more enriched.

Dust, volcanic ash, and the evolution of the South Pacific Gyre through the Cenozoic

We examine the 0–100 Ma paleoceanographic record retained in pelagic clay from the South Pacific Gyre (SPG) by analyzing 47 major, trace, and rare earth elements in bulk sediment in 206 samples from seven sites drilled during Integrated Ocean Drilling Program Expedition 329. We use multivariate statistical analyses (Q-mode factor analysis and multiple linear regression) of the geochemical data to construct a model of bulk pelagic clay composition and mass accumulation rates (MAR) of six end-members, (post-Archean average Australian shale, rhyolite, basalt, Fe-Mn-oxyhydroxides, apatite, and excess Si). Integrating the results with Co-based age models at Sites U1365, U1366, U1369, and U1370, we link changes in MAR of these components to global oceanographic, terrestrial, and climatic transformations through the Cenozoic. Our results track the spatial extent (thousands of kilometers) of dust deposition in the SPG during the aridification of Australia. Dispersed ash is a significant component of the pelagic clay, often comprising >50% by mass, and records episodes of Southern Hemisphere volcanism. Because both are transported by wind, the correlation of dust and ash MAR depends on the site's latitude and suggests meridional shifts in the position of atmospheric circulation cells. The hydrothermal MARs provide evidence for rapid deposition from the Osbourn Trough spreading ridge before it went extinct. Excess Si MARs show that the abrupt increase in siliceous productivity observed at Site U1371 also extended at least as far north as Sites U1369 and U1370, suggesting large-scale reorganizations of oceanic Si distributions ~10–8 Ma in the southern SPG.

Knowledge, Attitudes Toward, and Acceptability of Genetic Modification among Western Balkan University Students of Life Sciences (AGREE Study)

Background: There are still no data on the attitudes and acceptance of genetic modification (GM) food in European developing countries, such as the Western Balkan countries. The aim of the study was to assess the knowledge, attitudes, and acceptance of GM but also to shed light on the multifactorial process leading to acceptance of genetic modifications among Western Balkan students of life sciences.Methods: In this cross-sectional study, the final study population sample was composed of 1251 university students. The instrument for data collection was a questionnaire consisting of 49 items composed of 5 sections taken from the literature. Attitudes toward GM were analyzed by using Q-mode factor analysis and principal component analysis was run for the assessment of perception of personal health risks. The acceptability of GM was analyzed in binary probit models assessing the acceptability of GM products in different areas of application with Q models, sociodemographic variables, perception of personal health risks factors, respondents' knowledge about biotechnology, gender, and age as explanatory variables.Results: This study demonstrated that students of life sciences supported the implementation of GM in industry and medicine production but not in food production. Their acceptance was most influenced by 3 out of 5 attitude models that were identified (p < 0.0001). Regarding the perception of personal health risks, the factor “credence risks” was seen as a negative predictor of acceptance of GM in industry and food production (p < 0.05). The main knowledge predictor of rejecting GM was misconception, whereas real knowledge had no impact (p < 0.0001).Conclusion: The AGREE study provided the first rough picture of the knowledge, attitudes, and acceptance of GM in this area. Given the target population, it could be expected that the general population's acceptance of all observed elements, especially knowledge, would be lower.