Lithium as a Silicate Weathering Proxy: Problems and Perspectives

The lithium concentration of the dissolved load from the Lena River, together with major element chemistry and GIS-based area and runoff data demonstrate the importance of evaporites in controlling dissolved Li in river waters. Eighty-four percent of the Li in the dissolved load of upper Lena tributaries comes from evaporites in these drainage basins. Altogether, at least ~20% of the total Li flux of the Lena River originates from this source. This finding has important implications for using lithium as a proxy for silicate weathering. The Li flux and the ⁸⁷Sr/⁸⁶Sr ratio are compared in order to address a difference between the two silicate weathering rate proxies. The proposed controls on the dissolved δ⁷Li values in rivers (kinetic vs. equilibrium isotopic fractionation; Rayleigh-type preferential extraction of the heavy isotope) (Huh et al., Earth Planet Sci Lett 194:189–199, 2001) are evaluated using data from both the Siberian rivers and the Orinoco River. Neither of the proposed mechanisms satisfactorily explains the comprehensive data set. Instead, a ‘mineralogy-specific view’ that emphasizes the difference in the secondary mineralogy (i.e., fractionation factor) is presented as a potential rationalization in the form of the refined Rayleigh-type extraction.     

Two different geomentalities,two different gardens: the French and the Japanese cases

The French Renaissance gardens and Japanese hill gardens have constrasting garden landscapes. Japanese gardens are naturalistic and intend to give illusions that they are the beautiful spots of unspoilt nature. In contrast, the appearances of French gardens are not an imitation of nature but boldly reorganised landscapes in geometric forms. These two contrasting types of garden landscapes represent two different sets of geomentalities (frames of mind regarding geographical environment).An earlier draft of this paper was presented at the Ninth New Zealand International Conference on Asian Studies, Hamilton, 23–26 August 1991. Its abridged version is published in D. Bing and K. Henshell (ed.)Japanese Perceptions of Nature and the Natural Order (Hamilton, NZ 1992), pp. 1–11. The present paper was developed from the first half of the conference paper, and was completed during my three month's tenure in 1993 as a Japan Foundation fellow. I am grateful to the Japan Foundation for their generous support of my research on the Japanese geomentality.     

Reviews of recent Australian publications

AUSTRALIA: A GEOGRAPHY. Volume 1: The Natural Environment edited by D. N. Jeans. 18 × 25 cm, viii and 347 pages. Sydney University Press: Sydney 1986 (ISBN 0 424 00114 4) $A55.00 (hard); (ISBN 0 424 00124 1) $A32.50 (soft).

Western Australia. Departments of Education and Lands and Survey (1979) Western Australia: an atlas of human endeavour, 1829–1979, Government Printer, Perth.

ATLAS OF SOUTH AUSTRALIA edited by T. Griffin and M. McCaskill. 28 × 40 cm, xiv and 134 pages. South Australian Government Printing Division and Wakefield Press on behalf of the South Australian Jubilee 150 Board: Adelaide 1986 (ISBN 0 7243 46880) $A55.00 (hard).

URBAN AUSTRALIA: Planning Issues and Policies edited by S. Hamnett and R. Bunker. 16 × 24 cm, 192 pages. Nelson Wadsworth: Melbourne 1987 (ISBN 0 17 007166 9) $A29.95 (hard).

AUSTRALIAN URBAN DEVELOPMENT AND INTERNATIONAL FINANCE CAPITAL (Working Paper No. 31) by M. T. Daly. 21 × 30 cm, viii and 39 pages. Transnational Corporations Research Project, University of Sydney 1985 (ISBN 0 908470 66 5) $A5.00 (soft).

TRANSNATIONAL CAPITAL AND URBANIZATION IN JAPAN (Research Monograph No. 25) by M. Douglass. 21 × 30 cm, viii and 42 pages. Transnational Corporations Research Project, University of Sydney 1987 (ISBN 0 908470 74 6) $A10.00 (soft).

MELBOURNE WESTERN REGION: Industrial Sites Atlas by Melbourne Western Region Joint Working Group. 45 × 32 cm, 40 pages. Melbourne Western Region Joint Working Group: Melbourne 1984 $A20.00 (soft).

MINE INFRASTRUCTURE AND ECONOMIC DEVELOPMENT IN NORTHERN AUSTRALIA by C. O'Faircheallaigh. 18 × 25 cm, vi and 87 pages. North Australia Research Unit, Australian National University: Darwin 1987 (ISBN 0 7315 0043 1) $A10.00 (soft).

AUSTRALIA'S CHANGING POPULATION: Trends and Implications by G. Hugo. 16 × 24 cm, x and 354 pages. Oxford University Press: Melbourne 1986 (ISBN 0 19 554680 6) $A40.00 (hard).

WOMEN OVER SIXTY: A Study of the Housing, Economic and Social Circumstances of Older Women (Publication No. 130) by L. Coleman and S. Watson. 17 × 24 cm, v and 89 pages. Australian Institute of Urban Studies: Canberra 1987 (ISBN 0 86419 112 X).

THE MANNING VALLEY: Landscape and Settlement 1824–1900 by W. K. Birrell. 21 × 29 cm, xvi and 280 pages. Jacaranda: Milton, Qld, 1987 (ISBN 0 7016 2170 2) $A29.95 (hard).

ISSUES IN THE MANAGEMENT OF AUSTRALIA'S WATER RESOURCES by J. J. Pigram. 15 × 23 cm, xvi and 331 pages. Longman Cheshire: Melbourne 1986 (ISBN 0 582 71139 8) $A24.95 (soft).

PROSPECTS FOR HARDWOOD FORESTS (Monograph No. 19) edited by J. Dargavel and G. Sheldon. 16 × 23 cm, xv and 334 pages. Centre for Resource and Environmental Studies, Australian National University, Canberra 1987 (ISBN 0 86740 226 1) $A19.95 plus $A5.00 post and packing (soft).

FOREST SOILS AND NUTRIENT CYCLES by P. M. Attiwill and G. W. Leeper. 15 × 22 cm, x and 202 pages. Melbourne University Press: Melbourne 1987 (ISBN 0 522 84315 8) $A29.90 (hard).

AUSTRALIAN SOILS: The Human Impact edited by J. S. Russell and R. F. Isbell. 26 × 18 cm, xi and 522 pages. University of Queensland Press: St Lucia 1986 (ISBN 0 7022 1968 1) $A50.00 (hard).

THE AUSTRALIAN SUMMER MONSOON, TELECONNECTIONS, AND FLOODING IN THE LAKE EYRE BASIN (South Australian Geographical Papers No. 2) by R. J. Allen. 18 × 25 cm, 47 pages. Royal Geographical Society of Australasia (South Australian Branch): Adelaide 1985 (ISBN 0 909112 09 6).     

Vessel-related contamination of Southern California harbours by copper and other metals

A number of trace contaminants appear to be introduced to nearshore marine waters as a result of vessel-related activities. Such inputs are clearly reflected by elevated concentrations of these constituents in several tissues of the bay mussel Mytilus edulis. Comparative studies using this bioindicator suggest that harbour-related activities can be as important a source as coastal wastewater discharges in the contamination of nearshore marine ecosystems.     

Fisheries/oil report

Incidence of shell disease in shrimp is as high as 30% in certain localities in the New York Bight. Gross examination and histopathological preparations revealed cracking and pitting of the exoskeleton, common characteristics of crustacean shell disease, followed by necrosis of underlying tissue. Aquarium studies, which included tests of the effects of an antibiotic, indicated a possible infectious etiology. The disease may be related to pollution of the habitat by organic wastes including cellulose.     

Delineation of recharge patterns and contaminant transport using 3H–3He in a shallow aquifer contaminated by chlorinated solvents in South Korea

Stable isotopes of water and ³H–³He were used to delineate recharge patterns and contaminant transport for a granitic regolith aquifer in an industrial complex in Wonju, South Korea, that has historically been contaminated with chlorinated solvents including trichloroethene (TCE) and carbon tetrachloride (CT). Groundwater recharge mainly occurred in upgradient forested areas while little recharge occurred in the downgradient industrial areas covered with extensive sections of impermeable pavement and paddy fields. δ¹⁸O and δD data indicated that groundwater was mainly derived from summer precipitation. The apparent groundwater ages using ³H–³He ranged from 1 to 4 yrs in the upgradient area and from 9 to 10 yrs in the downgradient area. Comparison of groundwater flow velocities based on Darcy’s law and those calculated with simple mass balance models and groundwater age supported the presence of preferential pathways for TCE movement in the study area. Measureable TCE was observed in groundwater irrespective of groundwater age. Considering the 3-yr duration of the TCE spill, 14 yrs before sampling, this indicates that TCE plumes were continuously fed from sources in the unsaturated zone after the spill ended and moved downgradient without significant degradation in the aquifer.     

Valence state of titanium in the Wark-Lovering rim of a Leoville CAI as a record of progressive oxidation in the early Solar Nebula

Simon et al. (2005) reported low Ti³⁺/Ti⁴⁺ values in Ti-rich pyroxenes in the Wark-Lovering rim (WL) of a Leoville CAI (144A) as compared to the interior of the inclusion. These electron microprobe analyses were interpreted as evidence that the growth of the WL rim is the manifestation of an evolution to a more oxidizing environment. Further work by Simon et al. (2007) used XANES analyses to argue for higher Ti³⁺ abundances and interpreted the data of Simon et al. (2005) as the result of X-ray contamination by neighboring phases, specifically spinel. Late-stage alteration was also included as a possible explanation.To investigate further the oxidation state of Ti in WL rims, we re-analyzed Leoville 144A to obtain a more complete data set of Ti³⁺/Ti⁴⁺ values in the Wark-Lovering rims. We conducted experiments on spinel-mixing to determine whether this was a plausible explanation for the observed paucity of Ti³⁺ in WL rims. While we found a wider range of Ti³⁺/Ti⁴⁺ in these WL rim data than in our original study, our new data show that the original conclusion that rims are lower in Ti³⁺/Ti⁴⁺ than interiors remains valid. We conclusively rule out spinel-mixing as an explanation for our data, and we see no clear inconsistency between our electron microprobe data and the XANES data. The WL rim of CAI Ef3 was also analyzed by EMPA and compared to the results of Leoville 144A.To predict compositional consequences of this hypothesis, we constructed a reaction space between Ti-rich pyroxene in the WL rim, perovskite, Mg_(g), Ca_(g), O_2(g), and SiO_(g). We find the oxidation of Ti³⁺, coupled with Ti loss via perovskite formation, explains many features of WL rim EMPA analyses. We maintain that the WL rim pyroxenes are compositionally distinct from those in the interior, and are evidence of a more oxidizing environment during WL rim formation.     

Burial-dominated cementation in non-tropical carbonates of the Oligocene Te Kuiti Group, New Zealand

Cementation of bryozoan-echinoid-benthic foraminiferal temperate shelf carbonates of the Oligocene Te Kuiti Group, North Island, New Zealand, occurred mainly during subsurface burial. The calcite cements in the limestones are dominated by equant and syntaxial rim spar which typically becomes ferroan (given an iron supply) and, compared to the skeletal material with normal marine δ¹⁸O values from +2 to −1‰, more depleted in ¹⁸O with depth of burial, the δ¹⁸O composition of bulk cement samples ranging from −1 to −7‰. These trends reflect the establishment in pore waters during sediment burial of reducing conditions and gradually increasing temperatures (20–50°C), respectively. The δ¹³C values (0 to +3‰) of the cements remain the same as the host marine shells, suggesting the source of carbon in the cements was simply redistributed marine carbonate derived from shell dissolution.

Two gradational burial diagenetic environments influenced by marine-derived porewaters are arbitrarily distinguished: shallow burial phase and moderate burial phase. During the shallow burial phase, down to 500–600 m sub-bottom depth, the carbonates lost at least 25% of their original porosity by mechanical compaction and were selectively cemented by non-ferroan or usually ferroan, variably luminescent, slightly ¹⁸O-depleted sparry calcite cement (δ¹⁸O −2 to −4‰), mainly as syntaxial rims about echinoid grains. These shallow-burial cements form less than about 10% of total cement in the majority of the limestones and their source was probably mainly mild intergranular dissolution of calcitic skeletal fragments accompanying the onset of chemical compaction. During the moderate burial phase, between about 600 and 1100 m sub-bottom depth, porosity loss continued (typically to about 70% of its original value) as a result of pressure-solution of calcitic bioclasts associated with more advanced stages of chemical compaction. This involved development of a wide variety of non-sutured and microstylolitic solution seams, including both single and composite, wispy or continuous, bedding-parallel types and non-parallel reticulate forms. The released carbonate was precipitated as ferroan (or non-ferroan where iron supply was negligible), dull luminescent, strongly ¹⁸O-depleted (δ¹⁸O −4 to −7‰), mainly equant calcite spar cement, occluding available pore space in the limestones.     

Marine Dissolved Organic Phosphorus Composition: Insights from Samples Recovered Using Combined Electrodialysis/Reverse Osmosis

The dominant phosphorus compound classes were characterized in marine samples using a new, high recovery method for isolating and concentrating bulk dissolved organic matter (DOM) called combined electrodialysis + reverse osmosis (ED/RO). In contrast to earlier studies that use ultrafiltration (UF) to recover only the high molecular weight DOM, ED/RO is capable of isolating both low molecular weight (LMW) and high molecular weight (HMW) DOM. Samples were collected from a broad range of marine environments: along a transect incorporating coastal and offshore waters off the Southeastern United States, in Effingham Inlet, a Pacific fjord located on Vancouver Island, British Columbia and in the Amundsen Sea, Antarctica. Results from phosphorus nuclear magnetic resonance (³¹P NMR) analysis reveal a similar abundance of P compound classes among samples, phosphate esters (80–85%), phosphonates (5–10%) and polyphosphates (8–13%). These samples contain significantly higher proportions of polyphosphate P and P esters and lower proportions of phosphonates than measured in previous studies using the UF method. The much higher levels of polyphosphate detected in our samples suggests that polyphosphate is present mainly in the LMW dissolved matter fraction. Polyphosphates in dissolved matter may be present as (or derived from) dissolved nucleotides or organismal polyphosphate bodies, or both. Low molecular weight P esters are possibly composed of phosphoamino acids and small carbohydrates, like simple sugar phosphates and/or dissolved nucleotides. Phosphonates in DOM are more prevalent as HMW phosphonate compounds, which suggests that LMW phosphonates are more readily utilized in marine ecosystems. Overall, the investigation of DOM across a size spectrum that includes both the HMW and the LMW fractions reveals a new picture of phosphorus distribution, cycling and bioavailability.     

Stratigraphic and tectonic settings of Proterozoic glaciogenic rocks and banded iron-formations: relevance to the snowball Earth debate

Among Palaeoproterozoic glacial deposits on four continents, the best preserved and documented are in the Huronian on the north shore of Lake Huron, Ontario, where three glaciogenic formations have been recognized. The youngest is the Gowganda Formation. The glacial deposits of the Gowganda Formation were deposited on a newly formed passive margin. To the west, on the south side of Lake Superior, the oldest Palaeoproterozoic succession (Chocolay Group) begins with glaciogenic diamictites that have been correlated with the Gowganda Formation. The >2.2 Ga passive margin succession (Chocolay Group=upper Huronian) is overlain, with profound unconformity, by a >1.88 Ga succession that includes the superior-type banded iron-formations (BIFs). The iron-formations are therefore not genetically associated with Palaeoproterozoic glaciation but were deposited 300 Ma later in a basin that formed as a result of closure of the “Huronian” ocean. In Western Australia, Palaeoproterozoic glaciogenic deposits of the Meteorite Bore Member appear to have formed part of a similar basin fill. The glaciogenic rocks are, however, separated from underlying BIF by a thick siliciclastic succession. In both North America and Western Australia, BIF-deposition took place in compressional (possibly foreland basin) settings but the iron-formations are of greatly different age, suggesting that the most significant control on their formation was not oxygenation of the Earth’s atmosphere but rather, emplacement of Fe-rich waters (uplifted as a result of ocean floor destruction?) in a siliciclastic-starved environment where oxidation (biogenic?) could take place. Some of the Australian BIFs appear to predate the appearance of red beds in North American Palaeoproterozoic successions and are therefore unlikely to be related to oxygenation of the atmosphere.Neoproterozoic glaciogenic deposits are widespread on the world’s continents. Some are associated with iron-formations. Two theories have emerged to explain these enigmatic BIFs. According to the snowball Earth hypothesis (SEH), ice-covered oceans would have permitted buildup of dissolved Fe. Precipitation of Fe-rich sediments would have taken place following reoxygenation of the hydrosphere as the ice cover disappeared. A second theory involves glaciation of Red Sea rift-type basins. Fe-charged brines in such basins would have precipitated on being mixed with “normal” seawater as a result of glacially driven thermal overturn. Both theories provide an explanation of the hydrothermal imprint on the geochemistry of Neoproterozoic BIF but the restricted development of BIF (relative to glacial deposits), evidence of rift activity such as significant facies and thickness changes, and association with volcanic rocks, all favour deposition in a rift environment.Cap carbonates are one of the cornerstones of the SEH. Escape from the snowball condition is said to have resulted from buildup of atmospheric CO₂ while the weathering cycle was stopped. Under such conditions, the first siliciclastic deposits following glaciation, should be extremely weathered, and should be overlain by sedimentary rocks that show a gradual return to more “normal” compositions. Using a chemical index of alteration (CIA) it can be shown that, in the case of the Gowganda Formation, the CIA shows a gradual upward increase, opposite to that predicted by the SEH. The Earth underwent severe climatic perturbations both near the beginning and end of the Proterozoic Eon but whether it attained a totally frozen surface condition (as postulated under the SEH) remains speculative.