Post-fire recovery of Puya raimondii,vegetation and birds in the puna of Huascarán National Park,Perú     

Mery L.SUNI  Giovana P.VADILLO  César ARANA  Enoc JARA-PE?A  Letty SALINAS  M.Estela PONCE  Paul M.RAMSAY 《山地科学学报》2024,(1):20-32

A large fire of 233 ha in Huascarán National Park in Peru provided an opportunity to compare plant and bird responses in burned and nearby unburned zones of the puna. Heights and live diameters of flagship Puya raimondii rosettes(assigned to four broad developmental phases), plant communities(66 species in 24 families and nine growth forms) and bird communities(77 species in six trophic guilds) were monitored after the fire. Although no mortality was observed, Puya raimondii plants were affected...  相似文献   

A simple guideline to apply excitation-emission matrix spectroscopy (EEMs) for the characterization of dissolved organic matter (DOM) in anoxic marine sediments     

Shuchai Gan  Verena B.Heuer  Frauke Schmidt  Lars W?rmer  Kai-Uwe Hinrichs 《海洋学报(英文版)》2023,42(1):109-119

Marine sediments represent a major carbon reservoir on Earth. Dissolved organic matter(DOM) in pore waters accumulates products and intermediates of carbon cycling in sediments. The application of excitation-emission matrix spectroscopy(EEMs) in the analysis of subseafloor DOM samples is largely unexplored due to the redoxsensitive matrix of anoxic pore water. Therefore, this study aims to investigate the interference caused by the matrix on EEMs and propose a guideline to prepare pore water sam...  相似文献   

Ground-borne vibrations induced by impact pile driving: experimental assessment and mitigation measures     

Aires Cola?o  A.M.Abouelmaty  P.Alves Costa 《地震工程与工程振动(英文版)》2023,(1):105-115

Impact pile driving is an interesting technique for the construction of deep foundations from a practical and economical point of view. However, the generalization of this technique can be restricted due to the excessive vibration levels that can be generated, which can be especially problematic in residential areas. However, different mitigation measures can be applied to prevent excessive vibration levels inside buildings located near construction sites. To compare its efficiency through a num...  相似文献   

三万五千年以来的海平面     

约翰D?米里曼  K?O埃默里 《海洋科学》1979,3(4):59-60

美国大西洋陆架35,000年来的海平面曲线,是建立在80多个放射性碳年代的基础上,其中15个年代是老于15,000年代的。测年的材料包括浅水软体动物、鲕状岩、珊瑚藻、海滩岩和盐沼泥炭。30,000—35,000年前的海平面,曾经是接近于现在的海平面的。随后冰川发育,16,000年前海平面降低到负130米左右。全新世海侵可能开始于约14,000年前,并迅速地延续到约7,000年前。世界大多数大陆架的年代和这条曲线相一致,说明这条曲线大致是这个时期海平面升降的曲线。  相似文献   

Relationship between the Vitória-Ecoporanga Dyke Swarm and the Vitória Structural High, Brazil     

Camilo I. Ordó?ez ARISTIZáBAL  André Luiz FERRARI 《《地质学报》英文版》2016,90(Z1):145-150

正In Espírito Santo State,Brazil,between the municipalities of Vitória,Colatina and Ecoporanga,there is a mountainous region characterized by a shear zone which trends NNW-SSE and is filled by a diabase dyke  相似文献   

Distribution and U-Pb Ages of Newly Recognized Regional-Scale Dyke Swarms of the Leo Man Craton     

L. BARATOUX  M.W. JESSELL  U. S?DERLUND  R.E. ERNST  M. BENOIT  S. NABA  C. COURNèDE  S. PERROUTY  V. METELKA  D. YATTE  D.P. DIALLO  P.M. NDIAYE  D. BARATOUX 《《地质学报》英文版》2016,90(Z1):29-29

正Over 20 sets of dolerite dykes crosscutting Paleoproterozoic basement in West Africa were distinguished via the interpretation of regional and high resolution magnetic airborne data of West African Craton  相似文献   

The Diagenesis of Plant Lipids during the Formation of the Krepoljin Coal Basin (Serbia) — Using Multivariate Statistical Analysis in the Saturated Biomarkers     

Gordana DEVI?  Branimir JOVAN?I?EVI? 《《地质学报》英文版》2008,82(6):1168-1178

The composition of the saturated hydrocarbon fraction of soluble organic matter (bitumen) from the Krepoljin brown coal basin (East Serbia) of Miocene age was investigated. The Krepoljin basin is especially interesting from a geochemical point of view. Namely, by the end of Tertiary Period, the basin was covered by powerful Mesozoic formations of great possibilities, the bedding became hermetically enclosed and protected from subsequent external influences. The nature of early diagenetic processes in the environment with abundant accumulation of organic substance is defined by the molecular content of bitumen through the connections of molecular structures to potential precursors in paleoplant phylla, as well as by the degree of their diagenetic transformations. The hierarchy of parameters based on molecules of saturated hydrocarbons was determined by applying the principal component analysis to the soluble organic matter. The most significant, most “loadings” values of component C1, are the plant types such as precursors or participants in early diagenetic transformations of steranes Cs27-algal precursor material, Cs28-moulds, Cs29-higher land and water plants; resinous from the group of higher plant gymnosperms (G); also triterpanes α and β-amirin-dicotyledonous angiosperms (A) and bacterial and/or terrestrial plants population represented by hopanes/moretanes; as well as the parameters which describe the degree of diagenetic/maturation transformation of precursor biomass, and based on next reactions: (1) shifting of methyl group, influenced by the inorganic sediment constitutents, sterane-rearranged steranes, (2) isomerization in the ring system, ααα→βββ C29 sterane as well as (3) isomerization on chiral center of the side chain sequence R→S C29 sterane S/(S+R). Additionally, a pyrite-derived inhibitory effect on the rearrangment of C29 steranes must be taken into account, but not on triterpanes reaction. Non-appearance of statistically important correlations, before all with maturational depended parameters, and after all also with source indicators contributies to the affirmation of the newly-suggested parameter α-Phyllocladane/S27 as the real source biomarker of coal. Indicators derived from the distribution and abundance of n-alkanes and isoprenoid alkanes are of less significance in hierarchy of parameters.  相似文献   

Macroscopically‐Zoned Grandite from the Garnetite Skarn of Meka Presedla (Kopaonik Mountain,Serbia)     

Pavle Tan?i?  Predrag Vuli?  Reinhard Kaindl  Bernhard Sartory  Radovan Dimitrijevi? 《《地质学报》英文版》2012,86(2):394-405

The macroscopically-zoned grandite from the garnetite skarn of Meka Presedla (Kopaonik Mountain, Serbia) was studied with optical microscopy, electron microprobe analysis (EMPA), Fourier transform infra-red (FT–IR), and Raman methods. The EMPA results indicate that the main core–rim compositional variations (Ca2.93–2.97Mn0.05–0.06Mg0.00–0.01Al1.14–1.26Fe3+0.72–0.83Ti0.00–0.02Si2.97–3.02O12) slightly differ along the zones, showing evidence for a quasi-cyclic alternation of the oscillatory zoning nature. Among this, considerable variation is observed only by the Al–Fe3+ substitutions in the octahedral site. The EMPA also indicate that the grandite zones compositionally vary, mostly within ±1 and ±2 mol% of the homogeneity level range, that is, Grs64±1Adr36±1Sps2 (A), Grs62±1Adr38±1Sps2 (B), Grs59±2Adr40±2Sps2 (C), Grs58±2Adr41±2Sps2 (D), and Grs58±1Adr41±1Sps2 (E). Therefore, the investigated garnet can be considered as relatively highly homogeneous. The majority of compositions lie within the narrow miscibility region of 0.58±2相似文献   

Crystal Structure and Chemical Composition of Ludwigite from Vranovac Ore Deposit (Boranja Mountain,Serbia)     

Pavle TAN?I?  Radovan DIMITRIJEVI?  Maja POZNANOVI?  Aleksandar PA?EVSKI  Slobodanka SUDAR 《《地质学报》英文版》2012,86(6):1524-1538

The crystal structure of ludwigite from Vranovac ore deposit (Boranja Mt., Serbia) was refined using the X-ray powder diffraction (XRPD) Rietveld method in the space group Pbam to a final RB=7.45% and RF=5.26%. It has the unit cell dimensions of: a=9.2515(2) ?; b=12.3109(2) ?; c=3.03712(7) ?; and V=345.91(1) ?3. The calculated distances and angles are mostly in good agreement with the Mg2+-Fe2+ substitutions across the M(1) and M(3) sites, as well as with the Fe3+-Al3+ replacement in the M(4) site. However, the mean observed M(2)-O distance is considerably shorter than prescribed, due to a slight increase of the Fe3+ content in the M(2) site. Such replacement was compensated by slight increase of the Fe2+ content in the M(4) site, resulting in the (Mg1.48Fe2+0.46Fe3+0.05Mn0.02)2.01(Fe3+0.94Fe2+0.04Al0.02)1.00B1.00O5 composition. The formation temperature was estimated to be about 500–600°C. The influences of the various chemical compositions to the crystallographic parameters, M-O distances, M(3) and M(4) sites shift, distortion parameters and estimated valences, were also studied and compared with other reference samples.  相似文献   

A New Species of Megarhyphus,an Interesting Discovery from the Lower Jurassic of England(Diptera,Anisopodidae)   总被引：1，自引：1，他引：0  

Krzemińska EWA  Coram A. ROBERT  Krzemiński WIES?AW 《《地质学报》英文版》2010,84(4):693-695

<正>The oldest representative of the genus Megarhyphus Kovalev(Diptera:Anisopodidae)is described from the Lower Jurassic(Sinemurian)of England.A summary of our knowledge of Jurassic Anisopodidae is given.  相似文献