Evaluating cost-effective strategies for meeting regional CO2 targets

Various climate protocol proposals oblige different industrialized countries to reduce CO₂ and other greenhouse gas emissions. In principle, the total costs of these obligations could be substantially reduced if emission reductions are implemented in regions with low marginal costs for CO₂ reduction. This has been difficult to quantify because of lack of models with suitable regional and sectoral detail. In this paper we perform these calculations by taking advantage of the capability of the IMAGE 2 model to compute regional emissions and costs. Two main options are examined for allocating emission reductions required of industrialized regions in a cost effective manner: (1) allocating them among industrialized regions (2) allocating them among all world regions. The cost savings for each of these options are presented. The main conclusions are that (a) it is of great importance for the cost comparisons of protocols to use a well defined baseline scenario and clearly formulated targets, and (b) large economic benefits, in the order of 35–65%, can accrue from joint-implementation agreements which allocate investments on the basis of net marginal costs of CO₂ emission reduction.     

Integrating disaster risk reduction into post‐disaster reconstruction: A long‐term perspective of the 1931 earthquake in Napier,New Zealand

This article is a long‐term retrospective study of the reconstruction that followed the 1931 earthquake that struck the city of Napier in Hawke's Bay, New Zealand. It particularly focuses on the positive outcomes in reducing the risk of future disaster at both local and national levels. These were facilitated by three key decisions and strategies: (i) reconstruction was initiated immediately after the disaster; (ii) it was designed as a balance between continuity and change; and (iii) it relied on a decentralised, integrative decision‐making process.     

The north-eastern Polish anorthosite massifs: petrological, geochemical and isotopic evidence for a crustal derivation

ABSTRACT Deeply buried 1.5 Ga Polish anorthosites, accessible only by bore holes, reveal diagnostic features of some massif-type anorthosites (polybarism, jotunitic parent magma), diapirically emplaced in the mid crust together with the rapakivi granites of the EW-trending Mazury complex, intruded along a major crustal discontinuity. Geochemical modelling and isotope data corroborate recent experimental work on the basaltic system in dry conditions: the source rock of the parental magma is a gabbronorite, necessarily lying in the lower crust. Since no Archaean crust is known in the region, high initial ¹⁸⁸Os/¹⁸⁷Os ratios for sulphide-oxide isochrons and negative ε_Nd values are best accounted for by melting a ∼ 2.0 Ga mafic crust.     

Rapid fish stock depletion in previously unexploited seamounts: the case of Beryx splendens from the Sierra Leone Rise (Gulf of Guinea)

Fish stocks associated with seamounts may be particularly susceptible to overexploitation. From January to July 2001, the Spanish Oceanographic Institute (IEO) conducted an experimental fishing survey entitled ‘Palguinea-2001’ on the seamounts of the Sierra Leone Rise. Beryx splendens (commonly called alfonsino) is the main commercial demersal fish associated with this area. The aim of this study was to investigate the effects of a demersal longline fishery targeting B. splendens on the previously unexploited small Machucambo Seamount over a short time-scale, and also to consider trends in pooled catch rate at another four seamounts. During 110 fishing days at Machucambo, a total catch of 207 tonnes of B. splendens was taken with a fishing effort of 1 309 070 hooks. A spectral analysis and red-noise spectra procedure (REDFIT) algorithm was used to identify the red-noise spectrum from the gaps in the observed time-series of catch per unit effort by weight. Our results show the potential impact of longline fishing pressure on an unexploited ecosystem – after approximately 50 fishing days, the stock appeared to decline substantially, as reflected by a marked drop in catch per unit effort. The apparent rapid decline of the stock might be related to the small size and the virgin state of the Sierra Leone seamounts. The results could be extrapolated to similar small seamounts elsewhere.     

Geochemistry of cumulates from the Bjerkreim–Sokndal layered intrusion (S. Norway). Part I: Constraints from major elements on the mechanism of cumulate formation and on the jotunite liquid line of descent

Whole-rock major element compositions are investigated in 99 cumulates from the Proterozoic Bjerkreim–Sokndal layered intrusion (Rogaland Anorthosite Province, SW Norway), which results from the crystallization of a jotunite (Fe–Ti–P-rich hypersthene monzodiorite) parental magma. The scattering of cumulate compositions covers three types of cumulates: (1) ilmenite–leuconorite with plagioclase, ilmenite and Ca-poor pyroxene as cumulus minerals, (2) magnetite–leuconorite with the same minerals plus magnetite, and (3) gabbronorite made up of plagioclase, Ca-poor and Ca-rich pyroxenes, ilmenite, Ti-magnetite and apatite. Each type of cumulate displays a linear trend in variation diagrams. One pole of the linear trends is represented by plagioclase, and the other by a mixture of the mafic minerals in constant proportion. The mafic minerals were not sorted during cumulate formation though they display large density differences. This suggests that crystal settling did not operate during cumulate formation, and that in situ crystallization with variable nucleation rate for plagioclase was the dominant formation mechanism. The trapped liquid fraction of the cumulate plays a negligible role for the cumulate major element composition. Each linear trend is a locus for the cotectic composition of the cumulates. This property permits reconstruction by graphical mass balance calculation of the first two stages of the liquid line of descent, starting from a primitive jotunite, the Tjörn parental magma. Another type of cumulate, called jotunite cumulate and defined by the mineral association from the Transition Zone of the intrusion, has to be subtracted to simulate the most evolved part of the liquid line of descent. The proposed model demonstrates that average cumulate compositions represent cotectic compositions when the number of samples is large (> 40). The model, however, does not account for the K₂O evolution, suggesting that the system was open to contamination by roof melts. The liquid line of descent corresponding to the Bjerkreim–Sokndal cumulates differs slightly from that obtained for jotunitic dykes in that the most Ti-, P- and Fe-rich melts (evolved jotunite) are lacking. The constant composition of the mafic poles during intervals where cryptic layering is conspicuous is explained by a compositional balance between the Fe–Ti oxide minerals, which decrease in Fe content in favour of Ti, and the pyroxenes which increase in Fe.     

Petrogenesis of monzonoritic dykes in the Egersund-Ogna anorthosite (Rogaland,S.W. Norway): trace elements and isotopic (Sr,Pb) constraints

Two major monzonoritic dykes occur in the Egersund-Ogna anorthositic massif (S.W. Norway): the Lomland dyke, which varies from norite to monzonite, and the Vettaland ferronoritic dyke. They are characterized by high Fe, Ti and P contents, low SiO₂, variable K₂O (0.5%–4.5%) and high Fe/Mg ratios. Small variations in REE distribution are observed inside the Lomland dyke [La/Yb=12; LREE ca. 150–180 (chondrite-normalized values), neutral to slightly positive Eu anomaly]. Part of the Vettaland dyke is severely depleted in Zr, Rb and REE and shows a positive Eu anomaly. All rocks are depleted in U and Th, and show very low Cr and Ni contents, as well as high Sr contents (400–600 ppm). Variation within the Lomland dyke is satisfactorily ex-plained through subtraction of an apatite-bearing noritic cumulate. The role of apatite is predominant in controlling the REE behaviour. Eutectic partial melting of a Fe-rich noritic cumulate (containing apatite) under low pH₂O conditions is suggested for the Vettaland dyke by REE modelling. Sr isotopic initial ratios are different in Lomland (ca. 0.708) and Vettaland (ca. 0.706) dykes. These values preclude direct derivation from the mantle as well as comagmatic relationship with anorthosite. Contamination of a mantle derived magma by deep crustal material or anatexis of the LIL depleted lower crust is compatible with the low U and Th contents, and with the Pb isotopic ratios. The Vettaland partial melting process is extended to all monzonoritic types, the necessary heat being provided by the high temperature anorthositic crystal mush. Chargé de Recherches du F.N.R.S (Belgium)     

Fluid inclusions in charnockites from the Bjerkreim-Sokndal massif (Rogaland,southwestern Norway): fluid origin and in situ evolution

Fluid inclusions and mineral associations were studied in late-stage charnockitic granites from the Bjerkreim-Sokndal lopolith (Rogaland anorthosite province). Because the magmatic and tectonic evolutions of this complex appear to be relatively simple, these rocks are a suitable case for investigation of the origin and evolution of granulitic fluids. Fluid inclusions, primarily contained in quartz, can be divided into four types: carbonic (type I), N₂-bearing (type II), CO₂+H₂O (type III) and aqueous inclusions (type IV). For each type, the role of leakage and fluid mixing are discussed from microthermometric and Raman spectrometric data. The most striking features of CO₂-rich inclusions (the predominant fluid) is the presence of graphite in numerous, trail-bound inclusions (Ib) and its absence in a few isolated, very dense (d=1.16), pure CO₂ inclusions (Ia) and in the late carbonic inclusions (Ic). Fluid chronology and mineral assemblages suggest that carbonic Ia inclusions represent the first fluid (pure CO₂) trapped at or close to magmatic conditions (T=780–830° C, fO₂=10^-15 atm and P=7.4±1 kb), outside the graphite stability field. In contrast, type Ib inclusions enclosed graphite particles from a channelized fluid during retrograde rock evolution (P=3–4 kb and T=600° C). Decreases in T-fO₂ could explain a progressive evolution from a CO₂-rich fluid to an H₂O-rich fluid in a closed C–O–H system. However, graphite destabilization observed in type Ic inclusions implies some late introduction of external water during the last stage of retrogression. The main results of this study are the following: (1) a carbonic fluid was present in an early stage of rock evolution (probably in the charnockitic magma) and (2) this granulite occurrence offers good evidence of crossing the graphite stability field during post-magmatic evolution.     

New evidence of slope instability in the Outardes Bay delta area, Quebec, Canada

The Outardes Bay delta constitutes one of the best sites to study the formation of failure deposits in a modern lowstand environment. These deposits are located in a pseudo-shelf-edge position along the northern part of the Laurentian Channel in the St. Lawrence Estuary. The site has been investigated over the past 20 years with a Raytheon model RTT1000 boomer (3.5 kHz, 400 J) on the shelf, and most recently with a Simrad model EM 1000 multibeam sonar (95 kHz) on the slope to provide high-resolution seismic and bathymetric data. The seismic data show wavy, chaotic and contorted reflectors which are typical in marine environments characterised by instability features. The multibeam sonar data have revealed many slope instability features such as creep folds, channel incisions, debris flows, and rotational slide scars. Thus, these interpreted features are in direct relationship with the seismic interpretation of the data collected upslope. These geomorphological and geophysical signatures express both past and present sedimentological processes. Some of the mass movement signatures observed in the surveyed area are believed to be related with the great MS~7 Charlevoix earthquake in 1663.     

New evidence of slope instability in the Outardes Bay delta area, Quebec, Canada

The Outardes Bay delta constitutes one of the best sites to study the formation of failure deposits in a modern lowstand environment. These deposits are located in a pseudo-shelf-edge position along the northern part of the Laurentian Channel in the St. Lawrence Estuary. The site has been investigated over the past 20 years with a Raytheon model RTT1000 boomer (3.5 kHz, 400 J) on the shelf, and most recently with a Simrad model EM 1000 multibeam sonar (95 kHz) on the slope to provide high-resolution seismic and bathymetric data. The seismic data show wavy, chaotic and contorted reflectors which are typical in marine environments characterised by instability features. The multibeam sonar data have revealed many slope instability features such as creep folds, channel incisions, debris flows, and rotational slide scars. Thus, these interpreted features are in direct relationship with the seismic interpretation of the data collected upslope. These geomorphological and geophysical signatures express both past and present sedimentological processes. Some of the mass movement signatures observed in the surveyed area are believed to be related with the great MS~7 Charlevoix earthquake in 1663.     

The use of geochemical methods to characterize the metamorphic domain in the Belgian ardennes

In the Belgian Ardennes anticline, low-grade metamorphism has locally affected the sil topelitic Lower Devonian formations. In the metamorphic domain, the Ti content of stream sediments is very high ( >0.17%), giving rise to a widespread regional Ti anomaly. This anomaly faithfully follows the limits of the metamorphic external zone proposed by Beugnies (1986). This is due to the appearance of ilmenite in the metamorphosed rocks and its subsequent concentration in the stream sediments. A statistical study of major- and trace-element contents of rocks sampled outside the metamorphic domain indicates a strong correlation between Ti and Al, K and Rb, suggesting that the Ti content is related to the illite content of the samples. Ti is therefore washed away with the clay fraction in the weathering process leading to stream sediment formation. Indeed, outside the metamorphic area, Ti is not involved in the main factors governing trace-element distribution in the stream sediments. The use of stream sediment geochemical prospecting provides a confirmation of petrological and structural work and may thus help in the accurate mapping of metamorphism limits.