(Table 1) Organic carbon isotopic composition in Cretaceous sediments at DSDP Hole 75-530A

Cretaceous sediments from DSDP Site 530 have been analyzed for organic carbon isotopic composition. The d13C values in the sediments decrease from -22.7 per mil to -27.5 per mil in the following order: light-olive green mudstone/claystone, dark brown-red mudstone/siltstone/claystone, and black shale. This large range is primarily the result of variation in the relative amounts of terrestrial organic carbon superimposed on that derived from marine organisms. The black shales have an average d13C value of -25.9 per mil (range is from -23.7 per mil to -27.5 per mil). These values indicate that they originated primarily in terrigenous organic materials. The average d13C value present throughout the Cretaceous suggests that a large amount of terrestrial organic matter was supplied into this paleoenvironment, except during the Campanian, when an average d13C of -23.9 per mil is found near the marine end of the range.

Microplankton abundance and biomass in the Eastern Pacific

Particles of detritus were counted by size-groups and microplankton cells in samples stained with acid fuchsin and acridine orange. Data were obtained for eutrophic and oligotrophic waters. Seston in the eutrophic layer of eutrophic waters consists of 22-65% phytoplankton, 3-18% microzooplankton, and 32-65% detritus; in oligotrophic waters - of 3-7% phytoplankton, 1-5% microzooplankton, and 92-97% detritus. Amount of detritus in seston increases with depth up to 4.4 µg C/l (sigma = 1.48) at 500-4000 m. Microplankton biomass in deep water contains mostly olive-green cells and bacteria; no microzooplankton <200 µm long was found below 200 m. Aggregates 10-50 µm in diameter and fragments of organisms 50-200 µm long were dominant by weight among detrital particles. No discernible associations of microorganisms with detrital particles were observed.

Cretaceous calcareous nannofossils of DSDP Leg 77 holes

Five of the six sites drilled during Leg 77 of the Deep Sea Drilling Project yielded Cretaceous sediments. Two of these sites, 535 and 540, form a composite section that spans the upper Berriasian through most of the Cenomanian. Olive black marly limestones in this interval yield relatively rich, well-preserved nannofossil assemblages that allow biostratigraphic subdivision of the sequence. This composite section provides important information on the Early Cretaceous history of the Gulf of Mexico, as well as additional information on tropical Lower Cretaceous nannofossil assemblages. The post-Cenomanian nannofossil (and sedimentary) record is limited to a thin, condensed section of Santonian through lower Maestrichtian pelagic sediments at one site (538) and is absent or represented by redeposited material at the other sites. Two new genera, Perchnielsenella and Darwinilithus, are described. Two new taxa, Darwinilithus pentarhethum and Lithraphidites acutum ssp. eccentricum, are described; and two new combinations, Rhagodiscus reightonensis and Perchnielsenella stradneri, are propose.

(Table 1) Summary of accelerator mass spectrometer (AMS) radiocarbon ages in ODP Sites 169-1033 and 169-1034

Continuous coring in Saanich Inlet (Ocean Drilling Program, ODP Leg 169S), British Columbia, Canada, yielded a detailed record of Late Quaternary climate, oceanography, marine productivity, and terrestrial vegetation. Two sites (1033 and 1034) were drilled to maximum depths of 105 and 118 m, recovering sediments ranging in age from 13,300 to less than 300 14C yr. Earliest sediments consist of dense, largely massive, gray glaciomarine muds with dropstones and sand and silt laminae deposited during the waning stages of glaciation. Deposition of organic-rich olive gray sediments began in the fjord about 12,000 14C yr ago, under well-oxygenated conditions as reflected by the presence of bioturbation and a diverse infaunal bivalve community. At about 10,500 14C yr, a massive, gray unit, 40-50 cm thick, was emplaced in a very short span of time. The unit is marked by a sharp lower contact, a gradational upper contact and an abundance of reworked Tertiary microfossils. It has been interpreted as resulting from massive flood events caused by the collapse of glacial dams in the Fraser Valley of mainland British Columbia. Progressively greater anoxia in bottom waters of Saanich Inlet began about 7000 14C yr ago. This is reflected in the preservation of varved sediments consisting of diatomaceous spring-summer laminae and terrigenous winter laminae. Correlation of the sediments was based on: marked lithologic changes, the presence of massive intervals (reflecting localized sediment gravity flow events), the Mazama Ash, occasional thin gray laminae (indicative of abnormal flood events in nearby watersheds), varve counts between marker horizons, and 71 accelerator mass spectrometry (AMS) radiocarbon dates.

Geochemistry at DSDP Hole 69-504B

Cores from Deep Sea Drilling Project Holes 501, 504B and 505B have an unusual near-vein zonation in basalts. Megascopically, zonation occurs as differently colored strips and zones whose typical thickness does not exceed 6 to 7 cm. Microscopically, the color of zones depends on variably colored clay minerals which are the products of low-temperature hydrothermal alteration in basalt. These differently colored zones form the so called "oxidative" type of alteration of basalts. Another "background," or, less precisely termed, "non-oxidative," type of alteration in basalts is characterized by large-scale, homogeneous replacement of olivine, and filling of vesicles and cracks by an olive-brown or olive-green clay mineral. The compositions of clay minerals of the "background" type of alteration, as well as the composition of co-existing titanomagnetites, were determined with an electron microprobe. There are sharp maxima in potassium and iron content, and minima in alumina, silica, and magnesia in clay minerals in the colored zones near veins. Coloring of clay and rock-forming minerals by iron hydroxides and a decrease of the amount of titanomagnetite, which apparently was the source of redeposited iron, occur frequently in colored zones. We assume that the large-scale "background" alteration in the basalts occurred under the effect of pore waters slowly penetrating through bottom sediments. Faulting can facilitate access of fresh sea water to basalts; thus above the general homogeneous background arise zones of "oxidative" alteration along fractures in basalts. The main factors controlling these processes are time (age of basalt), grain size, temperature, thickness of sedimentary cover, and heat flow.

Major-oxides and trace-elements at DSDP Hole 78-543A

Four chemically distinct basalts were cored in 44 m of basement penetration at Deep Sea Drilling Project Site 543, in Upper Cretaceous crust just seaward of the deformation front of the Barbados Ridge and north of the Tiburon Rise. All four types are moderately fractionated abyssal tholeiites. The four types have different magnetic inclinations, all of reversed polarity, suggesting eruption at different times which recorded secular variation of the earth's magnetic field. Extensive replacement of Plagioclase by K-feldspar has occurred at the top of the basalts, giving analyses with K2O contents up to 5 %. The earliest stages of alteration were dominantly oxidative, resulting in fractures lined with celadonite and dioctahedral smectite, and pervasive replacement of olivine and most intersertal glass with iron hydroxides and green clay minerals. Latef, non-oxidative alteration resulted in formation of olive-green clays and pyrite veins in a portion of the rocks. Basalts affected by this alteration actually lost K2O (to abundances lower than in adjacent fresh basalt glasses), and gained MgO (to abundances higher than in the glasses). Finally, fractures and interpillow voids were lined with calcite, sealing in much fresh glass. Oxygen-isotope measurements on the calcite indicate that this occurred at 12 to 25C. Either altering fluids were warm or the basalts had become buried with a considerable thickness of sediments, such that temperatures increased until a conductive thermal gradient was established, when the veining occurred.

Products of chlorophyll diagenesis from DSDP Leg 57 Holes

Tetrapyrrole pigments isolated from sediments retrieved during Leg 57 include pheophytin-a, a myriad of chlorins, free-base deoxophylloerythroetioporphyrin (DPEP), as well as copper and nickel porphyrins. Their richness, both qualitatively and quantitatively, in chlorin tetrapyrroles affords a relatively complete study on the early diagenesis of chlorophyll. Our studies, coupled with those in the preceding chapter by Louda et al., point out the influence of pre- and postdepositional environments upon the mode of chlorophyll diagenesis. Formation of tetrapyrroles, collectively called "petroporphyrins," is seen to occur in only a limited set of environmental conditions (see Baker and Palmer, 1978). The more generalized route of chlorophyll diagenesis, at least in the ocean, results in removal of tetrapyrrole pigment, from the fossil record. Late diagenetic products, metalloporphyrins, are found to represent an extremely minor component of the tetrapyrrole assemblage in sediments studied from the Japan Trench. The products of chlorophyll diagenesis isolated from Japan Trench sediments allow expansion of previous diagenetic schemes (Baker and Palmer, 1978; Triebs, 1936) and indicate directions for future studies.

Geochemistry at DSDP Leg 62 Holes

A total of 191 samples was collected for inorganic geochemical analyses from DSDP Holes 463, 464, 465, 465A, and 466. These samples were collected with two main goals. First, at least one sample was collected from each core, whenever possible, to document the general geochemical variability within lithologic units. Unfortunately, several lithologic units were inadequately sampled because of poor recovery, mostly due to the presence of chert. The least-sampled units are Units III in Hole 464 and Units IB and II in Hole 466. The second goal was to look for geochemical differences between contrasting lithologies within main lithologic units, particularly between cyclic interbeds of red and green limestone in Lithologic Unit II, Hole 463, and between olive, laminated limestone and gray, massive limestone in Lithologic Unit II, Hole 465A.

Raster maps for 29 environmental variables in three geographical regions

Aim: Greater understanding of the processes underlying biological invasions is required to determine and predict invasion risk. Two subspecies of olive (Olea europaea subsp. europaea and Olea europaea subsp. cuspidata) have been introduced into Australia from the Mediterranean Basin and southern Africa during the 19th century. Our aim was to determine to what extent the native environmental niches of these two olive subspecies explain the current spatial segregation of the subspecies in their non-native range. We also assessed whether niche shifts had occurred in the non-native range, and examined whether invasion was associated with increased or decreased occupancy of niche space in the non-native range relative to the native range. Location: South-eastern Australia, Mediterranean Basin and southern Africa. Methods: Ecological niche models (ENMs) were used to quantify the similarity of native and non-native realized niches. Niche shifts were characterized by the relative contribution of niche expansion, stability and contraction based on the relative occupancy of environmental space by the native and non-native populations. Results: Native ENMs indicated that the spatial segregation of the two subspecies in their non-native range was partly determined by differences in their native niches. However, we found that environmentally suitable niches were less occupied in the non-native range relative to the native range, indicating that niche shifts had occurred through a contraction of the native niches after invasion, for both subspecies. Main conclusions: The mapping of environmental factors associated with niche expansion, stability or contraction allowed us to identify areas of greater invasion risk. This study provides an example of successful invasions that are associated with niche shifts, illustrating that introduced plant species are sometimes readily able to establish in novel environments. In these situations the assumption of niche stasis during invasion, which is implicitly assumed by ENMs, may be unreasonable.

Sediment texture, carbonate content, and carbonate mineralogy of ODP Holes 182-1130A and 182-1132B

At Sites 1130 and 1132 of Ocean Drilling Program Leg 182 in the Great Australian Bight, we recovered an expanded Pleistocene section dominated by packstone and wackestone, deposited at unusually high rates of >20 cm/k.y. Shipboard observations detected an intermittent meter-scale alternation of light gray intervals with olive-gray intervals. Meter-scale samples were collected from the upper 250 m at both sites and decimeter-scale samples from four selected 2.5- to 4.0-m intervals in order to determine the texture and composition of sediments deposited along the upper slope throughout the Quaternary. Detailed textural and compositional data are presented from a total of 540 samples collected from both sites. Results indicate a general coarsening upward at both sites, with an accompanying upcore increase in high-Mg calcite (HMC) and aragonite and a decrease in low-Mg calcite (LMC). Samples collected at decimeter-scale intervals substantiate that the alternating light gray and olive-gray units detected on board ship are lithologically distinct. Light gray units consist of an LMC-rich silt, whereas olive-gray units consist of an aragonite and HMC-rich sand and silt. Sediment sources as well as timing and controls of this cyclic depositional pattern will be the subject of further investigations.

Geochemistry and minerals at DSDP Hole 70-504B

In three veins from the lower part of Deep Sea Drilling Project Hole 504B, 298 meters below the top of basement, primary augite is replaced by aegirine-augite. This transformation occurs only in subophitic basalts, at the contact with veins which always include a dark-olive, Mg-rich clay mineral. Talc occurs in one of these veins; it can be regarded either as a vein constituent or as a product of augite alteration. Melanite (Ca,Fe,Ti-rich garnet) appears in only one of these three veins, where a Ca-carbonate is associated with a Mg-rich clay mineral. The occurrence of melanite in Hole 504B could be due to the conjunction of particular conditions: (1) basalt with a subophitic texture, (2) presence of hydrothermal fluids carrying Ca, Fe, Si, Ti, Al, Mg, and Na, (3) rather high temperatures. Possibly the melanite and aegirine-augite formed by deuteric alteration.

Density of alkyl esters and its mixtures

Biodiesel density is a key parameter in biodiesel simulations and process development. In this work we selected, evaluated and improved two density models, one theoretical (Rackett-Soave) and one empirical (Lapuerta's method) for methanol based biodiesels (FAME) and ethanol based biodiesel (FAEE). For this purpose, biodiesel was produced from vegetable oils (sunflower, rapeseed, soybean, olive, safflower and other two commercial mixtures of vegetable oils) and animal fats (edible and crude pork fat and beef tallow) using both methanol and ethanol for the transesterification reactions, and blended to get 21 FAME and 21 FAEE, reporting their density and detailed composition. Bibliographic data have also been used. The Rackett-Soave method has been improved by the use of a new acentric factor correlation, whereas the parameters of the empirical one are improved by considering a bigger density data bank. Results show that the evaluated models could be used to estimate the biodiesel density with a good grade of accuracy but the performed modifications improve the accuracy of the models: ARD (%) for FAME; 0.33, and FAEE; 0.26, both calculated with the modification of Rackett-Soave method and ARD (%) for FAME; 0.40 calculated with the modification of the Lapuerta's method).

(Table 1) Minerals of bulk sediment at DSDP Holes 64-480 and 64-481

This paper provides a brief, descriptive, sedimentological background for the chapters on hydraulic piston core Site 480 in this symposium, and supplements data given in the site chapter for Sites 479-480 (this volume, Pt. 1). Sediments are composed primarily of planktonic diatoms, with minor numbers of silicoflagellates, radiolarians, and varying amounts of both benthic and planktonic foraminifers, along with a large terrigenous component of olive brown, silty clay. The section contains meter-thick intervals of finely laminated facies alternating with nonlaminated zones. A few paleoenvironmental events are documented within the generally uniform sequence by sporadic occurrences of thin turbidites, phosphatic concretions, fish debris concentrations, an ash layer, and a thin layer of diagenetic dolomite. The distribution of nonlaminated and laminated zones is attributed to fluctuations of bottom-water oxygen content caused by variations in circulation, fertility, and productivity. Homogeneous sections are interpreted as coinciding with cooler climatic periods, whereas laminated sections seem to correspond to upwelling conditions during drier periods.