Setting priorities for land management to mitigate climate change     

Böttcher H  Freibauer A  Scholz Y  Gitz V  Ciais P  Mund M  Wutzler T  Schulze ED 《Carbon balance and management》2012,7(1):5-18

Background

No consensus has been reached how to measure the effectiveness of climate change mitigation in the land-use sector and how to prioritize land use accordingly. We used the long-term cumulative and average sectorial C stocks in biomass, soil and products, C stock changes, the substitution of fossil energy and of energy-intensive products, and net present value (NPV) as evaluation criteria for the effectiveness of a hectare of productive land to mitigate climate change and produce economic returns. We evaluated land management options using real-life data of Thuringia, a region representative for central-western European conditions, and input from life cycle assessment, with a carbon-tracking model. We focused on solid biomass use for energy production.

Results

In forestry, the traditional timber production was most economically viable and most climate-friendly due to an assumed recycling rate of 80% of wood products for bioenergy. Intensification towards "pure bioenergy production" would reduce the average sectorial C stocks and the C substitution and would turn NPV negative. In the forest conservation (non-use) option, the sectorial C stocks increased by 52% against timber production, which was not compensated by foregone wood products and C substitution. Among the cropland options wheat for food with straw use for energy, whole cereals for energy, and short rotation coppice for bioenergy the latter was most climate-friendly. However, specific subsidies or incentives for perennials would be needed to favour this option.

Conclusions

When using the harvested products as materials prior to energy use there is no climate argument to support intensification by switching from sawn-wood timber production towards energy-wood in forestry systems. A legal framework would be needed to ensure that harvested products are first used for raw materials prior to energy use. Only an effective recycling of biomaterials frees land for long-term sustained C sequestration by conservation. Reuse cascades avoid additional emissions from shifting production or intensification.  相似文献   

A crustal origin for eclogites and a mantle origin for garnet peridotites: Strontium isotopic evidence from clinopyroxenes   总被引：1，自引：0，他引：1  

Hannes K. Brueckner 《Contributions to Mineralogy and Petrology》1977,60(1):1-15

Strontium isotopic data suggest that the classic eclogite-facies rocks of western south Norway described by Eskola (1921) formed from several parental materials in a variety of environments. Mineral separates from essentially basic, bi-minerallic (clinopyroxene and garnet) eclogites that occur as lens-shaped masses within high grade gneisses (country rock eclogites) have Sr⁸⁷/Sr⁸⁶ values that range from 0.704 for fine-grained varieties to 0.716 for coarse-grained, orthopyroxene-bearing varieties. These high, varied ratios contrast with the very low, restricted ratios (0.701 to 0.704) of similar minerals from ultrabasic, garnet-clinopyroxene-orthopyroxene-olivine assemblages (garnet peridotites) that occur as lenses within large peridotite bodies. The eclogite-facies metamorphism that generated the garnet peridotites may have occurred in the mantle. However, the metamorphism that generated at least the more radiogenic country-rock eclogites must have occurred in the crust. The high Sr⁸⁷/Sr⁸⁶ ratios of these eclogites could be generated either by forming them from crustal parental rocks or by contaminating mantle-derived parental rocks with radiogenic strontium from the country rocks. If this contamination occurred after intrusion and before eclogite-facies metamorphism, a rather contrived history must be postulated that involves intrusion, contamination accompanied by hydration, subsequent dehydration, and finally eclogite-facies metamorphism. These processes could have occurred within the long, complicated history of the enclosing country rocks. Alternatively, if the contamination occurred during eclogite-facies metamorphism, the presence of some hydrous fluid appears to be required to transport the radiogenic strontium from the enclosing country rocks. The eclogites with the highest Sr⁸⁷/Sr⁸⁶ ratios are also the most coarse-grained and it is possible that the presence of some intergranular fluid enabled these eclogites to recrystallize to a much larger grain size than would have been possible in a totally anhydrous environment. The garnet peridotites and fine-grained country rock eclogites may have formed from mantle material in the crust but escaped contamination by radiogenic strontium as a result of their position in a dry environment in the crust.Lamont-Doherty Geological Observatory Contribution No. 2443  相似文献   

Trace element and isotopic variations in a zoned pluton and associated volcanic rocks,Unalaska Island,Alaska: A model for fractionation in the Aleutian calcalkaline suite     

Michael R. Perfit  Hannes Brueckner  James R. Lawrence  Robert W. Kay 《Contributions to Mineralogy and Petrology》1980,73(1):69-87

Trace elements, including rare earth elements (REE), exhibit systematic variations in plutonic rocks from the Captains Bay pluton which is zoned from a narrow gabbroic rim to a core of quartz monzodiorite and granodiorite. The chemical variations parallel those in the associated Aleutian calcalkaline volcanic suite. Concentrations of Rb, Y, Zr and Ba increase as Sr and Ti decrease with progressive differentiation. Intermediate plutonic rocks are slightly enriched in light REE (La/Yb=3.45–9.22), and show increasing light REE fractionation and negative Eu anomalies (Eu/Eu^*=1.03–0.584). Two border-zone gabbros have similar REE patterns but are relatively depleted in total REE and have positive Eu anomalies; indicative of their cumulate nature. Initial ⁸⁷Sr/⁸⁶Sr ratios in 8 samples (0.70299 to 0.70377) are comparable to those of volcanic rocks throughout the arc and suggest a mantle source for the magmas. Oxygen isotopic ratios indicate that many of the intermediate plutonic rocks have undergone oxygen isotopic exchange with large volumes of meteoric water during the late stages of crystallization; however no trace element or Sr isotopic alteration is evident.Major and trace element variations are consistent with a model of inward fractional crystallization of a parental high-alumina basaltic magma at low pressures (6 kb). Least-squares approximations and trace element fractionation calculations suggest that differentiation in the plutonic suite was initially controlled by the removal of calcic plagioclase, lesser pyroxene, olivine and Fe-Ti oxides but that with increasing differentiation and water fugacity the removal of sub-equal amounts of sodic plagioclase and hornblende with lesser Fe-Ti oxides effectively drove residual liquids toward dacitic compositions. Major and trace element compositions of aplites which intrude the pluton are not adequately explained by fractional crystallization. They may represent partial melts derived from the island arc crust. Similarities in Sr isotopes, chemical compositions and differentiation trends between the plutonic series and some Aleutian volcanic suites indicates that shallow-level fractional crystallization is a viable mechanism for generating the Aleutian calcalkaline rock series.LDGO Contribution no. 2964  相似文献   

Origin of cosmic magnetic fields     

Hannes Alfvn 《Physics of the Earth and Planetary Interiors》1979,20(2-4):185-191

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“Mantle” Rb/Sr and 87Sr/86Sr ratios for clinopyroxenes from Norwegian garnet peridotites and pyroxenites     

Hannes K. Brueckner 《Earth and Planetary Science Letters》1974,24(1):26-32

Clinopyroxenes separated from garnetiferous ultramafic rocks in the core zone of the Norwegian Caledonides have rubidium concentrations of 0.008 to 0.064 ppm, strontium concentrations of 23.5 to 421 ppm, and ⁸⁷Sr/⁸⁶Sr ratios of 0.7011 to 0.7029. The very low Rb/Sr ratios of the clinopyroxenes (less than 0.0004) suggest that their ⁸⁷Sr/⁸⁶Sr values have not varied significantly over geologic time and may approximate the initial ⁸⁷Sr/⁸⁶Sr of the eclogite-facies ultramafic mineral assemblages at their time of formation. The ultramafic rocks occur in a basement complex that yields Rb-Sr whole-rock and U-Pb zircon ages of about 1800 m.y. Garnetiferous ultramafic rocks are apparently lacking in younger (Sveconorwegian or Caledonian) sialic sequences, raising the possibility that the eclogite-facies metamorphism may have occurred at least 1800 m.y. ago. The Rb/Sr and ⁸⁷Sr/⁸⁶Sr ratios of the clinopyroxenes are as predicted for the ancient upper mantle under most evolutionary models. However, the data do not preclude the possibility that the eclogite-facies metamorphism occurred in the crust. The garnetiferous ultramafic rocks are generally enclosed by large volumes of dunite which could have shielded the eclogite-facies assemblages from contamination by fluids from the country rock during metamorphism.  相似文献   

Cosmology: Myth or science?     

Hannes Alfvén 《Journal of Astrophysics and Astronomy》1984,5(1):79-98

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A vacuum sampler for subsampling freeze-dried laminated sediments with the application toin situ frozen varves of Mondsee,Austria     

Roland Schmidt  Hannes Höllerer  Gabriele Wallner 《Journal of Paleolimnology》1995,14(1):93-96

A method was developed for subsampling freeze-dried laminated sediments that employs a vacuum to draw off sediment from the sample in a precise way. The technique was tested on anin situ frozen sediment core of Mondsee containing varves 2 to 7 mm thick. Material was subsampled for¹³⁷Cs dating.  相似文献   

Sedimentation processes on the antarctic continental margin at Kapp Norvegia during the late Pleistocene     

Hannes Grobe 《International Journal of Earth Sciences》1986,75(1):97-104

Sedimentological analyses concerning ice rafted debris, grain size distribution, biogenous components, and clay mineral composition of four sediment cores from the Antarctic continental margin off Kapp Norvegia reveal a cyclical pattern of three different sediment facies. These are classified into warm and cold types representing warm and cold a climatic periods and short transition period from cold to warm events.The sedimentological parameters reflect the variations within the cryosphere and the hydrosphere, which are directly influenced by the climatic fluctuations. The unusually high content of carbonaceous planktonic and benthonic foraminifera in these polar sediments, as well as the interfingering of terrigeneous and biogeneous-rich sediments with increasing distance from the continent, might reflect the influence of the Weddell Sea Polynya and the oscillations of polynya, pack ice and ice shelf extent during the late Pleistocene.

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Zusammenfassung An vier Sedimentkernen eines Profils am antarktischen Kontinentalhang vor Kapp Norvegia wurden Eisfracht, biogene Komponenten, Korngrößenverteilungen und Tonmineralvergesellschaftungen bestimmt. Die Verteilung der sedimentologischen Parameter zeigt eine zyklische Abfolge von drei verschiedenen Sedimentfazies, die die klimatisch gesteuerten Veränderungen innerhalb der Hydrossphäre und der Kryossphäre widerspiegeln.Die drei Sedimentfazies werden warmen und kalten Klimaperioden sowie einer kurzen Übergangszeit zugeordnet. Der für polare Sedimente ungewöhnlich hohe Gehalt an kalkigen benthonischen und planktonischen Foraminiferen sowie die Verzahnung vorwiegend terrigener mit biogenreichen Sedimenten bei zunehmender Entfernung vom Kontinent lassen den Einfluß der Weddell See-Polynya und die Oszillationen von Schelfeiskante und Packeisbildung während des späten Pleistozäns erkennen.

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Résumé Des analyses sédimentologiques ont été effectuées sur 4 carottes prélevées le long d'un profil dans les sédiments de la marge continentale antarctique au large du cap Norvegia. Elles ont porté sur les débris amenés par les glaces, la granulométrie, les composants biogéniques et la composition des constituants argileux. Ces analyses révélent une succession cyclique de 3 facies sédimentaires; ceux-ci correspondent à des périodes climatiques chaudes et froides, ainsi qu'à de courtes périodes de transition du froid vers le chaud.Les paramètres sédimentologiques reflètent des variations de l'hydrosphère et de la cryosphère, directement influencées par les fluctuations climatiques. La teneur anormalement élevée de ces sédiments polaires en foraminif ères carbonatés planctoniques et benthoniques, ainsi que l'indentation de sédiments terrigènes et de sédiments riches en éléments biogéniques, peuvent traduire l'influence de la polyme de la Mer de Weddell, ainsi que les oscillations des surfaces occupées par la polynie, le pack et l'iceshelf, au cours du Pleistocène tardif.

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Tholeiitic Aleutian arc plutonism: The Finger Bay pluton,Adak, Alaska     

Suzanne Mahlburg Kay  Robert W. Kay  Hannes K. Brueckner  James L. Rubenstone 《Contributions to Mineralogy and Petrology》1983,82(1):99-116

The earliest representatives in the sequence of Tertiary to Recent magmatic rocks on Adak island in the central Aleutians, are the Finger Bay Volcanics and associated small shallow-level gabbroic intrusives. The tholeiitic Finger Bay pluton (gabbro to quartz monzodiorite) is among the least altered representatives of this earliest period. The field relations, mineralogy, and geochemistry of the Finger Bay pluton contrast with the more recent calcalkaline plutons in the arc (e.g. on Adak, Hidden Bay pluton: 33 m.y. and on Kagalaska, Kagalaska pluton: 15 m.y.). Compared with the Hidden Bay pluton, the Finger Bay pluton is smaller (8 km² versus 100 km²), has a greater proportion of gabbro (84% versus 5%), has a somewhat different mineralogy, and has higher whole rock and mafic mineral FeO/MgO ratios, higher K₂O, and higher concentrations of incompatable elements in rocks of equivalent SiO₂ (particularly for the more siliceous units). Magmatic amphibole occurs only in the most siliceous units in the Finger Bay pluton, whereas it is common in the calc-alkaline plutons. Except for the size, these differences parallel those between tholeiitic and calc-alkaline volcanic rocks from the active Aleutian volcanic centers. Textural, miner-alogical, and trace element analyses indicate that mixing of magmas and gabbros generated some of the rocks of intermediate (monzodiorite) composition in the Finger Bay pluton. Most of the differences in magmatic trends between the calc-alkaline and tholeiitic plutons are attributed to the physical conditions of magmatic evolution in the crust, rather than to differences in initial magmatic types. This conclusion rests on the similarity of fractionation-independent isotope ratios and trace element ratios in Aleutian magmas of all ages. In particular, compared to magmas of the north Pacific ocean basin (MORB, oceanic islands), Aleutian magmas show excess enrichment of Ba, K, Rb, and U relative to REE and high ²⁰⁷Pb/²⁰⁴Pb ratios for a given ²⁰⁶Pb/²⁰⁴Pb ratio. Recognition of tholeiitic series plutons in the arc provides direct evidence for magmatic conditions accompanying fractionation, and serves to emphasize the diversity of magmatic trends that are found over time and space at convergent plate margins.  相似文献   

Theory and Practice in Mathematical Geology—Introduction and Discussion     

Hannes Thierg?rtner 《Mathematical Geology》2006,38(6):659-665

Mathematical geology has developed into a very diverse system of mathematical models, algorithms and corresponding software. Experience shows that this diversification of approaches and methods was and is accompanied by an increasing gap between the availability of powerful tools and the continuation of many traditional working methods in the geosciences. Besides continuing to develop models, one of the basic functions of mathematical geology should be to introduce all new tools into practice and to aid non-specialized geoscientists to use them successfully and without bias. Some ways to do so will be briefly discussed here. Instructive and intelligible contributions towards attaining this goal were presented at the last (32nd) International Geological Congress held in Florence, Italy, in 2004. The intention of this present compilation is to suggest relevant discussions and conclusions. Mathematical geology should not be the domain of a few experts. It should be made accessible to all geologists and scientists in related fields.  相似文献