A Depletion Protocol for Non-Renewable Natural Resources: Australia as an Example

This paper examines the implications of statements by Australia’s Minister of… Resources that Australia’s exports of coal are growing rapidly and that Australia’s coal will last “110 years at current rates of production.” If one assumes that coal production P(t), follows a Gaussian curve (similar to a Hubbert curve) one can construct a family of Gaussian curves showing possible future paths of P(t) which are consistent with the cited “110 years.” Each curve reaches a maximum after which P(t) declines toward zero. Knowledge of the present value of dP/dt allows one member of the family to be identified as the most probable future path of P(t). Families of curves and tabular data are presented for resource quantities that would last 50, 100 and 200 years “at current rates of production.” If, instead, Australia’s P(t) follows a declining exponential curve (exp(−kt)) with k = (1/110) per year, the stated quantity of coal will allow production to continue forever, with P(t) declining with a half life of 76 y. This and more rapidly declining exponential paths are the only paths that can be said to be sustainable. The envelope of the family of Gaussian curves divides the (P, t) plane into “allowed” and “forbidden” areas. The declining exponential curve divides the “allowed” area into an upper area that is “terminal” and a lower area that is “sustainable.” These facts, coupled with Australia’s expectations of rapid growth of its population, suggest that Australia’s present resource policies are “anti-sustainable” and that the people of Australia need to rethink their present policy of rapidly exporting their fossil fuels.     

外部环境气象条件对日光温室气象条件的影响

应用2003年1～4月、10～12月在寿光蔬菜基地的日光温室内所取得的温度、光照和湿度资料及同一时期周围外部环境气象条件资料，分析了外部环境气象条件对日光温室内的温度、光照及湿度等气象条件的影响情况，在此基础上，提出了温室蔬菜生产中天气预报指导作用的简单思路。     

Characteristics and origins of primary fluids and noble gases in mantle-derived minerals from the Yishu area, Shandong Province, China

springerlink.com Studies of mantle fluids are currently one of the hot topics in the earth science, greatly contributing to re-vealing origins and evolutions of fluids. In general, the concept of mantle fluids refers to their active compo-nents, such as CO2, H2O, N2, etc., while the noble gases inert in chemical properties belong to another research system. Due to their marked differences in various fluid sources of the Earth[1], the isotopic sig-natures of He and Ar have been widely used a…     

The Late Jurassic Tithonian, a greenhouse phase in the Middle Jurassic–Early Cretaceous 'cool' mode: evidence from the cyclic Adriatic Platform, Croatia

Well‐exposed Mesozoic sections of the Bahama‐like Adriatic Platform along the Dalmatian coast (southern Croatia) reveal the detailed stacking patterns of cyclic facies within the rapidly subsiding Late Jurassic (Tithonian) shallow platform‐interior (over 750 m thick, ca 5–6 Myr duration). Facies within parasequences include dasyclad‐oncoid mudstone‐wackestone‐floatstone and skeletal‐peloid wackestone‐packstone (shallow lagoon), intraclast‐peloid packstone and grainstone (shoal), radial‐ooid grainstone (hypersaline shallow subtidal/intertidal shoals and ponds), lime mudstone (restricted lagoon), fenestral carbonates and microbial laminites (tidal flat). Parasequences in the overall transgressive Lower Tithonian sections are 1–4·5 m thick, and dominated by subtidal facies, some of which are capped by very shallow‐water grainstone‐packstone or restricted lime mudstone; laminated tidal caps become common only towards the interior of the platform. Parasequences in the regressive Upper Tithonian are dominated by peritidal facies with distinctive basal oolite units and well‐developed laminate caps. Maximum water depths of facies within parasequences (estimated from stratigraphic distance of the facies to the base of the tidal flat units capping parasequences) were generally <4 m, and facies show strongly overlapping depth ranges suggesting facies mosaics. Parasequences were formed by precessional (20 kyr) orbital forcing and form parasequence sets of 100 and 400 kyr eccentricity bundles. Parasequences are arranged in third‐order sequences that lack significant bounding disconformities, and are evident on accommodation (Fischer) plots of cumulative departure from average cycle thickness plotted against cycle number or stratigraphic position. Modelling suggests that precessional sea‐level changes were small (several metres) as were eccentricity sea‐level changes (or precessional sea‐level changes modulated by eccentricity), supporting a global, hot greenhouse climate for the Late Jurassic (Tithonian) within the overall ‘cool’ mode of the Middle Jurassic to Early Cretaceous.     

地面沉降根源分析与防治对策

地面沉降是普遍存在的一种地质灾害。人类经济社会的发展,尤其是城市化进程日趋加快,一些人类不合理的活动导致了地面沉降频繁发生,给生产、建设和人民生活造成极大的危害。要防治地面沉降发生,必须认清其产生的根源,方能收到药到病除的效果。本文采用归纳分析的方法,将地面沉降划分为5种类型,依据其产生的不同根源,有针对性地提出了预防和治理的措施。     

Development and evolution of water vapor vesicles during fast thermal breakdown of muscovite

At 1,175°C-1 bar, muscovite in natural granite powders is completely transformed after 5 min. Due to the overlapping of several processes such as dehydroxylation, mineralogical transformations, collapse and sintering of transformed lamellae, a few parts per thousand of H₂O vapor are trapped, generating bubbles in muscovite pseudomorphs. For short durations (5–40 min), the crystallographic properties of the precursor muscovite control the geometry of the bubbles that may be compared to thick disks with a rounded shape in basal sections and an elongated shape in lateral section, parallel to the former cleavage planes of muscovite. With longer durations the bubbles change from thick disks to spheres, which can be explained by the release of constraints perpendicular to basal planes upon growth of the high temperature Si–Al oxides. With time, the number of bubbles decreases while the bubble size and the porosity of the pseudomorphs increase. Bubble behavior was analyzed in terms of ripening, shape transformations and coalescence.     

Longitudinal distributions of two formation pathways of biogenic gases in continental deposits: A case study from Sebei 1 gas field in the Qaidam Basin, western China

The distribution of two formation pathways of biogenic methane, acetate fermentation and reduction of CO2, has been extensively studied. In general, CO2 reduction is the dominate pathway in marine envi- ronment where acetate is relatively depleted because of SRB consuming. While in terrestrial freshwater or brackish environment, acetate fermentation is initially significant, but decreases with increasing buried depth. In this paper, character of biogenic gases is profiled in the XS3-4 well of the Sebei 1 gas field in the Sanhu depression, Qaidam Basin. It indicates that those two pathways do not change strictly with increasing buried depth. CO2 reduction is important near the surface (between 50 m and 160 m), and at the mesozone (between 400 and 1650 m). While acetate fermentation is the primary pathway at two zones, from 160 to 400 m and from 1650 to 1700 m. δ 13C of methane generated in those two acetate fermentation zones varies greatly, owing to different sediment circumstances. At the sec- ond zone (160-400 m), δ 13C1 ranges from ?65‰ to ?30‰ (PDB), because the main deposit is mudstone and makes the circumstance confined. At the fourth zone of the well bottom (1650-1700 m), δ 13C1 is lighter than ?65‰ (PDB). Because the deposit is mainly composed of siltstone, it well connects with outer fertile groundwater and abundant nutrition has supplied into this open system. The high con- centration of acetate is a forceful proof. δ 13C of methane would not turn heavier during fermentation, owing to enough nutrition supply. In spite of multi-occurrence of acetate fermentation, the commercial gas accumulation is dominated by methane of CO2-reduction pathway. A certain content of alkene gases in the biogenic gases suggests that methanogensis is still active at present.     

The effect of volcanic eruptions on the chemistry of surface waters: The 1991 and 2000 eruptions of Mt. Hekla,Iceland

The Mt. Hekla eruptions in 1991 and 2000 have provided a unique opportunity to study the local environmental effects of high latitude volcanic eruptions in the middle of winter. Both eruptions started around sunset at sub-zero temperatures. In order to define better these effects we studied the chemistry of surface waters in the vicinity of the volcano. Additionally, we describe and predict the environmental consequences of these volcanic eruptions on the chemistry of surface waters on land and in the ocean.     

Iron Speciation of Mud Breccia from the Dushanzi Mud Volcano in the Xinjiang Uygur Autonomous Region, NW China

Organic-inorganic interactions occurring in petroleum-related mud volcanoes can help predict the chemical processes that are responsible for methane emissions to the atmosphere. Seven samples of mud breccia directly ejected from one crater were collected in the Dushanzi mud volcano, along with one argillite sample of the original reddish host rocks distal from the crater, for comparison purposes. The mineral and chemical compositions as well as iron species of all samples were determined using XRD, XRF and M?ssbauer spectroscopy, respectively. The results indicate that a series of marked reactions occurred in the mud volcano systems, more specifically in the mud breccia when compared to the original rocks. Changes mainly included: (1) some conversion of clay minerals from smectite into chlorite and illite, and the precipitation of secondary carbonate minerals such as calcite and siderite; (2) silicon depletion and significant elemental enrichment of iron, manganese, magnesium, calcium and phosphorus; and (3) transformation of iron from ferric species in hematite and smectite into ferrous species in siderite, chlorite and illite. These geochemical reactions likely induced the color changes of the original reddish Neogene argillite to the gray or black mud breccia, as a result of reduction of elements and/or alteration of minerals associated with the oxidation of hydrocarbons. Our results also suggest that greenhouse gases emitted from the mud volcanoes are lowered through a series of methane oxidation reactions and carbon fixation (i.e., through carbonate precipitation).