Stately home geology: the building stones of Tyntesfield Manor

Visiting a stately home open to the public can be a geological excursion in addition to a journey into social history. This is an experience akin to Darwin speculating whether his next landfall would present him with ‘igneous or metamorphic’ rocks to test his early geological knowledge, even before he had received Lyell's Principles when the Beagle reached Buenos Aires. In Britain the prospects are good when the house is Victorian or Edwardian, and we are facing the rich industrialists investing his wealth in opulent interiors within a High Gothic external architecture. In the West of England, this can be tested by a visit to Tyntesfield, a mansion acquired by the National Trust to the south of Bristol in South West England in 2002. Reputed to be little changed from being a family home, it has become a place where booking a timed visit is advised, such is public interest. It also has an added interest in that the Trust is in receipt of a grant from the Heritage Lottery Fund in order to carry out repairs and refurbishment of the many ancillary buildings of the landscaped estate. The work is proceeding alongside public visits, so offering insight into building conservation.     

A little goes a long way: discovery of a new mid-Holocene tephra in Sweden

This pilper reports the presence of a volcanic ash layer in western Sweden which is geochemically identiticd as the Kebister tephra. This tephrdpresenceof (dated c . 3600 ¹⁴C BP) was discovered at Kebister, Shetland and thc rcsults presented here indicate that the deposit may have a greater geographical distribution than previously thought. The geochemistry of the volcanic glass was analysed by using discrete grain electron probe microanalysis (EPMA). Thc SiO₂ content of the glass ranges from 66.19 to 71.96%, FeO content 2.73 to 6.07% and MgO content 0.15 to 0.57%_˜ The tephra can he distinguished from the more widespread Hekla 4 tephra ( c . 3800 ¹⁴C BP) on the basis of calcium and magnesium contents.     

It's a long way to the other geographers and geographic knowledges

Geographic knowledge is usually understood as the knowledge produced by geographers. Yet, it is also produced by people outside of the academia. But as Western science claimed for its exclusive self the status of ‘knowledge’, others have long been denied the production and possession of a true knowledge, and recognised merely the mastering of practical skills. The binary opposition between scientific and other forms of knowledge has been central to the construction of academic geography until the late 1980s, when postmodern thought cast some doubt on the universality of scientific knowledge. This led to critical analyses of academic geography, revealing its situatedness, as well as to a new interest for the geographies of the ‘Others’. Examining how geographers have dealt with other knowledge sets so far, and how they have labelled them, this paper argues that other geographies should be given more attention. This means focusing on the knowledges themselves, and considering implementing a true dialogue between these and academic geography. This revised version was published online in July 2006 with corrections to the Cover Date.     

体积排阻高效液相色谱-电感耦合等离子体质谱法同时测定印度芥菜(Brassica Juncea)中镉铜锌形态

螯合作用是植物对细胞内重金属耐受的主要方式之一,植物中螯合肽(PCs)在植物耐重金属毒害中的作用己有许多报道,但作用程度并未得出一致的结论,关于PCs是在镉刺激下直接合成还是以谷胱甘肽为底物合成同样存在争议。本文研究了胁迫浓度和胁迫时间对超积累植物印度芥菜(Brassica juncea)中镉形态分布的影响。印度芥菜幼苗分别用0.5、1.0、3.0、5.0、10.0 mg/L镉标准溶液胁迫24 h、48 h、72 h、96 h后收获,用体积排阻高效液相色谱-电感耦合等离子体质谱技术测定植物体根部和叶部中镉形态的含量。结果表明,在低胁迫浓度下(≤3.0 mg/L),植物叶中PCs-Cd的含量与胁迫浓度成正比;在高胁迫浓度下,PCs-Cd含量反而降低,根中PCs-Cd的含量持续增加,但叶中PCs-Cd总量高于根部,说明PCs在植物体内会由根部向叶部转移,从而提高了镉耐受性。在持续长时间胁迫下,PCs-Cd含量也降低,表明PCs在镉解毒机制中仅有短暂的作用;持续高浓度胁迫下,植物会引发其他机制来抵制Cd的毒性。研究认为PCs在镉解毒机制中的作用需要考虑胁迫时间和胁迫浓度这两个重要参数。     

建设创新型建筑业任重道远

在日前举办的首届建筑经济高峰论坛上，叶耀先教授就中国建筑业的技术进步和创新型企业的建立等有关问题接受了本刊的采访。叶教授在介绍中国建筑业情况时谈到，近几年来，中国建筑业的总产值所占份额逐年任提升，建筑业的就业人数占全国就业总人数的比重逐年增加，建筑业对其它行业的拉动作用在逐年增大，据不完全统计，建筑业每增加一亿元的产值，整个社会的总产值增加三亿元。     

We have come a long way, yet we still have far to go

Disaster experts around the world have continually warned governments and the public about the possibility of “worst-case” natural hazard scenarios and their overwhelming impacts. Yet, planning for the occurrence of these events has fallen far short of need. The large earthquake that occurred off the coast of Sumatra in 2004, which resulted in one of the deadliest tsunamis ever recorded, was a painful reminder that living in some of the most desirable areas of the world does have its risks. We all have enjoyed the fun of restful visits to coastal resort communities all around the world, and we rarely think about earthquakes or tsunamis interfering with this enjoyment. Yet, they take us by surprise. Before these events do occur, there should be adequate education for everyone on what actions are appropriate as well as an effective warning system to trigger the right actions.     

Myanmar and Asia united,Australia left behind long ago

It is well known that western Myanmar is underlain by a continental fragment, the West Burma Block, but there are arguments about its origin and the time of its arrival in SE Asia. This study presents the first petrological, XRD diffraction, heavy mineral and detrital zircon U-Pb age data from turbidite sandstones in the Chin Hills that were deposited on West Burma crust in the Triassic. These sandstones contain detritus derived from areas surrounding West Burma and thus help resolve arguments about its location in the Palaeozoic and Mesozoic. West Burma, Sibumasu and Western Australia have similar populations of Archean zircons derived from Western Australian cratons. Until the Devonian all formed part of the Gondwana supercontinent. The abundance of Archean zircons decreases from Western Australia to West Burma and then to Sibumasu. This is consistent with their relative positions in the Gondwana margin, with Sibumasu furthest outboard from Western Australia. Differences in zircon populations indicate that Indochina was not close to West Burma or Sibumasu in Gondwana. West Burma contains abundant Permian and Triassic zircons. These are unknown in Western Australia and different from those of the Carnarvon Basin; they were probably derived from SE Asian tin belt granitoids. Cr spinel is present in most West Burma sandstones; it is common in SE Asia but rare in Western Australia. These new data show that West Burma was part of SE Asia before the Mesozoic and support suggestions that the Argo block that rifted in the Jurassic is not West Burma.     

福建寿山高山石与坑头石的矿物学特征

运用显微硬度测试仪、静水称重法、X射线粉晶衍射仪、傅立叶红外光谱仪、原子吸收分光光度计、环境扫描电镜等测试手段,对福建寿山高山石和坑头石的矿物学特征进行了研究。结果表明,高山石含有多种高岭石族矿物,其中以地开石为主要矿物;坑头石中除含有地开石外,还存在相当数量的珍珠陶石以及地开石-高岭石、地开石-珍珠陶石的过渡矿物。认为寿山石的透明度与矿物颗粒的粒度、结晶程度有关。另外,发现铁离子为黑色寿山石的主要致色离子,寿山石中的裂解主要由矿物颗粒间定向排列造成。     

Paleovalley-related Uranium: Case-studies from Australia and China

Please?refer?to?the?attachment(s)?for?more?details.     

Inferring a deep-crustal source terrane from a high-level granitic pluton: the Strathbogie Batholith,Australia

The Strathbogie Igneous Complex is comprised of the ignimbritic rocks of the Violet Town Volcanics and the granitic rocks of the Strathbogie batholith. It is Late Devonian in age and postorogenic-extensional in tectonic setting. The batholith was constructed from peraluminous, metasediment-derived magmas emplaced as several internally heterogeneous plutons. Chemical variation in the magmas was largely inherited from the protolith rather than having been produced by differentiation (crystal–liquid separation) or magma mixing. The Strathbogie magmas formed during a granulite-facies metamorphic event that caused partial melting of the rocks of the Proterozoic Selwyn Block, which forms the basement in this region. The chemistry of the Strathbogie batholith, the Violet Town Volcanics and various other felsic complexes of similar age, implies that the Selwyn Block here originally consisted of andesite, dacite, greywacke and pelite, probably deposited in a back-arc extensional setting. The sedimentary components of this protolith may have been deposited in a basin that was extending and deepening with time, so that the sediments contained progressively higher ratios of clay to volcanic materials. Much later, in the Late Devonian, extensional tectonics allowed the emplacement of mantle magmas into the deep and middle crust, causing the low-pressure granulite-facies metamorphic event that was responsible for the production of the crustal components in the granitic magmas of Central Victoria.     

The imprinting of aridity upon a lateritic landscape: an illustration from southwestern Australia

The southwestern region of Australia contains the Yilgarn Craton that has been exposed to subaerial weathering since mid-Proterozoic. The gently undulating landscape experienced lateritic weathering so that today variably dissected, deep in situ isovolumetrically weathered regolith is widespread. Imposition of a more arid climate since the Miocene with the cessation of effective external drainage has resulted in substantial geochemical modification of the highly porous regolith. This vast pore volume acts as a reservoir for complex solutions that may be highly saline, extremely acid to alkaline and reducing. Diverse precipitates have formed in the regolith including widespread occurrence of silcrete, calcrete, dolocrete, ferricrete and gypcrete together with localised occurrences of pyrite, alunite, jarosite, barite, halite and other salts. Clearing of bush land for agriculture in the 20th century increased recharge so that rising chemically active groundwaters are damaging farmland and infrastructure throughout the region. To cite this article: B. Gilkes et al., C. R. Geoscience 335 (2003).     

Stepping stones and pitfalls in the determination of an anticlockwise P-T-t-deformation path: the low-P, high-T Cooma Complex, Australia

Abstract Low-pressure/high-temperature (low-P/high-T) metamorphic rocks of the Cooma Complex, southeastern Australia, show evidence of an anticlockwise pressure-temperature-time-deformation (P-T-t-D) path, similar to those of some other low-P/high-T metamorphic areas of Australia. Prograde paths are reasonably well constrained in cordierite-andalusite schists, cordierite-K-feldspar gneisses and andalusite-K-feldspar gneisses. These paths are inferred to be convex to the temperature axis, involving increase in pressure with increase in temperature. Evidence of the retrograde path is inconclusive, but is consistent with approximately isobaric cooling, as are available isotopic data on the Cooma Granodiorite, which indicate initially rapid cooling following attainment of peak temperatures. The retrograde path is inconsistent with either a clockwise P-T-t-D path involving rapid or even moderate decompression immediately post-dating the peak of metamorphism, or a path in which the retrograde component simply reverses the prograde component, because both these paths should cross reactions forming cordierite from aluminosilicate, for which no evidence has been observed. Determination of the deformational-metamorphic history of the complex is not straightfoward and depends on careful examination of critical samples. Evidence necessary for successful elucidation of the prograde, and part of the retrograde, deformational-metamorphic history in the Cooma Complex includes: (1) sequentially grown porphyroblasts that can be timed relative to surrounding foliations; (2) partial replacement microstructures providing relative timing of metamorphic reactions that cannot be timed relative to foliation development; (3) a tectonic marker foliation (S4 at Cooma) that allows correlation of foliations from one location to another; and (4) single samples containing all of the foliations and all generations of porphyroblast growth within a single metamorphic zone. The latest two or three foliations involve low strain accumulation, allowing relative timing relationships between foliations and porphyroblasts to be more clearly determined. Sequential porphyroblast growth and foliation development in the cordierite-andalusite schists is examined for situations involving rotation and non-rotation of porphyroblasts relative to geographically fixed coordinates. Although the number of foliations developed varies in the rotational situation, depending on the deformation history proposed, the sequential order of porphyroblast growths does not differ from the non-rotational situation. Thus, whether or not porphyroblasts rotated in the Cooma rocks, the sequence of reactions, and therefore P-T-t paths inferred from the relative timing of porphyroblast growths, remain the same, for the deformational histories evaluated.     

Groundwater calcrete deposits in Australia some observations from Western Australia

Groundwater calcretes are a non‐pedogenic form of calcrete occurring in broad fossil drainage systems. In Australia, they only occur north of about latitude 30°S and their formation requires arid conditions with very high potential evaporation as well as the periodic recharge of groundwater systems. They are linear, tabular limestone bodies, averaging about 10 m thick, occurring at or close to the surface and forming gentle mounds. The most extensive are located in the centre of the zone of distribution, where the climatic conditions are optimal, and are of the order of 100 km by 10 km. Some groundwater calcretes are fossil and strongly dissected, others are modern and still in process of formation.

A model of carbonate precepitation below the water table, i.e. in the phreatic zone, resulting in continuous calcrete growth, accounts for their morphology, their textures and the apparently inverted stratigraphy suggested by carbon‐14 dating. In areas of maximum growth, small anticlines develop which have structures engendered by both shear and concentric folding due to upward growth pressure.     

A chronology for the long pollen record from Lake Wangoom,western Victoria (Australia) as derived from uranium/thorium disequilibrium dating

The chronology of a long pollen record from Lake Wangoom, one of the few long palaeoenvironmental records from southeastern Australia, is discussed in light of the acquisition of new uranium/thorium disequilibrium (UTD) dates. Of crucial importance has been the estimation of ages for two major pre‐Holocene phases of forest expansion recorded in the sequence, with implications for the timing of periods of high effective precipitation in the region. The new UTD ages indicate that the oldest forest phase falls within the Penultimate Interglacial whereas the later phase corresponds with the Last Interglacial. This is older than indicated by previously reported UTD and radiocarbon dates, but confirms a chronology based on direct correlation with the pollen record from marine core E55‐6. The new chronology of the Lake Wangoom sequence provides evidence that phases of sustained forest development in southeast Australia relate to interglacial periods. In comparison, interstadial periods appear to be characterised by only minor arboreal development. Marked differences in the pattern of vegetation development evident in each of the interglacials are thought to reflect varying climatic and anthropogenic influences. Copyright © 2002 John Wiley & Sons, Ltd.     

Permian ammonoids from Eastern Australia

Umbrella‐shaped objects, presumably fossils, were collected from the Lower Proterozoic Noltenius Formation at two localities about 80 miles south of Darwin. Radial and concentric forms are described morphologically, and their probable mode of origin is discussed.     

Derivation of A-type Granites from a Dehydrated Charnockitic Lower Crust: Evidence from the Chaelundi Complex, Eastern Australia

Triassic I- and A-type granites of the Chaelundi Complex, NewEngland Fold Belt, eastern Australia, were generated in a subduction-relatedtectonic setting. Although isotopic ages of the suites are indistinguishable,field relations indicate that the A-type is younger. The mostmafic granitoids from each suite have similar silica contents(66–68% SiO₂), slightly LREE enriched patterns withoutEu anomalies, low Rb/Sr and K/Ba ratios, and high K/Rb ratios,suggesting that both represent parental magmas. The A-type isdistinguished mineralogically by abundant orthoclase and sodicplagioclase (total >60%), ferro-hornblende, annite and allanite.In contrast, the I-type has more hornblende and biotite, whichare more magnesian in composition, and less feldspar. The parentalmagmas of both suites have many similar geochemical characteristics,although the A-type has slightly higher alkalis, Zr, Hf, Znand LREE, and lower CaO, MgO, Sr, V, Cr, Ni and Fe³⁺/Fe. Thegeochemical properties characteristic of leucocratic A-typegranites, such as high Ga/Al, Nb, , HREE and F contents, areonly manifest in the more felsic members of the A-type suite.These features were produced by 70% fractional crystallizationof feldspar, hornblende, quartz and biotite. Both granite suites were generated by water-undersaturated partialmelting of a similar source, but the A-type parent magma resultedfrom lower aH₂O conditions during partial melting. Generationand rapid ascent of the earlier 1-type magma during disequilibriumpartial melting produced a relatively anhydrous, but not refractory,charnockitic lower crust. Continued thermal input from mantle-derivedmagmas, during continuing subduction, partially melted the ‘charnockitized’lower crust at temperatures in excess of 900C, to produce A-typemagmas. Charnockitic magmas (C-type) form in a similar way toA-type magmas, although their different composition reflectsvariations in the anhydrous lower-crustal mineral assemblagesthat remain after the previous (1-type) granite-forming event. The New England Fold Belt was a subduction—accretion complexuntil the late Carboniferous, when the deeper parts underwentpartial melting to produce S-type granites. As the I-and A-typegranites intruded penecontemporaneously, a tonalitic sourcemodel for genesis of the Chaelundi A-type is untenable. KEY WORDS: A-type; charnockitization; eastern Australia ^*Corresponding author.     

Major element geochemistry of silcrete from a portion of inland Australia

Silcrete is exceedingly uniform in composition, revealing no consistent variations across a large portion of the Australian interior. Analyses of host quartzose sediments suggest that a small increase in Si content, associated with a reduction in Al and H₂O, accompanied silcrete formation. Depletion of Fe, Mg, Ca, K and P point to intense leaching in a near-surface environment. Concentration of Ti during silicification is confirmed and attributed to accumulation from within the host sediments. Analyses of porcellanites derived from silicification of kaolinized claystones reflect considerable Si concentration, along with marked depletion of Al and other, more mobile elements. Reducing conditions under a wet climatic regime are postulated during the early phase of silcrete formation. Subsequent climatic change to aridity favoured silcrete development and preservation.