A new discovery of macroscopic fossils from the Ediacaran Doushantuo Formation in the Yangtze Gorges area

The Ediacaran section in the Yangtze Gorges area, South China, is one of the most important in the worldand contains abundant fossils[1-4]. The earliest discov- ery of macrofossils in 1984, including macroscopic algal fossils from the uppermost Doushantuo…     

Age of the Miyun dyke swarm: Constraints on the maximum depositional age of the Changcheng System

A group of NE-trending(～30°)mafic dykes,termed Miyun swarm herein,are distributed around the Miyun Reservoir,northe China,and have individual widths of over 40 m,and lengths of up to 8000 m.Baddeleyite grains were extracted from a～40 wide dyke.Using an isotope dilution thermal ionization mass spectrometry method,these grains yield an average 207Pb/206Pb a of 1731±4 Ma(n=4;or 1731±1 Ma,n=3).Because this dyke is overlain unconformably by conglomerates of the Changzhoug Formation,the lowermost formation of the Changcheng Group,the maximum depositional age of this group is constrained to no earlier than 1731 Ma.This result also suggests that the Changcheng System,with the Changcheng Group as its standard stra graphic section,is younger than 1731 Ma.The Miyun dykes possibly have distinct petrogenesis from the subsequent anorth site-rapakivi intrusions(1730-1680 Ma),which are thought to be responsible for the opening of the Yan-Liao rift,where Changcheng Group was deposited.Thus it is reasonable to set the initial boundary of the Changchengian Period at 1730 Ma slightly younger.     

Holocene climatic and environmental changes recorded in Baahar Nuur Lake core in the Ordos Plateau, Inner Mongolia of China

A 5.3 m lake core was drilled in Baahar Nuur Lake in the Ordos Plateau, and measurements of meangrain size, organic δ 13C (δ 13Corg), organic carbon content (TOC), C/N, carbonate content, carbonate δ 13C(δ 13Ccar) and δ 18O (δ 18Ocar) were conducted for retrieving the Holocene chronosequence of climaticchanges based on 15 AMS 14C dates. The record documented four major stages of climate change inthe Ordos Plateau: (IV) a cold and dry condition before ～7.65 14C ka BP; (III) a warm and humid stagebetween ～7.65 and ～5.40 ka BP; (II) a generally drier and cooler climate since ～5.40 ka BP with twohumid events occurring from ～4.70 to ～4.60 ka BP and from ～4.20 to ～3.70 ka BP, and (I) a dry climatecharacterized by complete desiccation of the lake after 3.70 ka BP. Stage III can be further divided intothree sub-stages: (IIIa) a warm and humid episode from ～7.65 to ～6.70 ka BP, (IIIb) a warm and relativelydry episode from ～6.70 to ～6.20 ka BP, and (IIIc) the magthermal and maghumid episode of the Holo-cene from ～6.20 to ～5.40 ka BP.     

Discovery of ∼4.0 Ga detrital zircons in the Changdu Block,North Qiangtang,Tibetan Plateau

Using in situ zircon dating by LA-ICP-MS and MC-ICP-MS, detrital zircon of 3981±9 Ma age was found in metamorphic rocks of the Ningduo Rock Group, Changdu Block of Northern Qiangtang. This is the oldest age record that has been found in the Qiangtang area. This finding also constitutes the third zircon locality in China with an age older than 3.9 Ga. Thus, the discovery provides new information for the study of Hadean crust. In addition, we found 3.51–3.13 Ga, ∼2440 Ma, ∼1532 Ma, ∼982 Ma and ∼618 Ma age peaks from 100 test spots. The younger ages of ∼982 Ma and ∼618 Ma correspond to the formation of the Rodinian super-continent and the Pan-African event, respectively. These findings suggest a close relationship between these zircons and the Gondwanan super-continent. The age of ∼618 Ma defines the lower limit on the deposit time of the protolith for the garnet-mica-quartz schist in the Ningduo Rock Group. Zircons with an age of ∼982 Ma generally display a negative ɛ_Hf(t) and a two-stage Hf model with concentrated ages around 1933–2553 Ma. This pattern indicates that the source area of the Ningduo Rock Group underwent a significant separation of depleted mantle into the crust during the Paleoproterozoic Era. However, zircons with ages of 2854–3505 Ma also show a negative ɛ_Hf(t) and a two-stage Hf model with a concentration of ages around 3784–4316 Ma. These results demonstrate that the source area of the Ningduo Rock Group contains a residual amount of ancient (Hadean) crustal materials. This paper provides new information on the relationship between the basement of the Qiangtang area and the Paleoproterozoic basements of the Gangdese and Himalayan regions, which constrains the northern boundary of Gondwana.     

An experimental study of dehydration melting of phengite-bearing eclogite at 1.5―3.0 GPa

Dehydration melting experiments were performed on ultrahigh-pressure eclogite from Bixiling in the Dabie orogen at 1.5--3.0 GPa and 800--950℃ using piston cylinder apparatus. The results show that （1） eclogite with -5% phengite started to melt at T≤800--850℃ and P = 1.5--2.0 GPa and produced about 3% granitic melt; （2） the products of dehydration melting of phengite-bearing eclogite vary with temperature and pressure. Fluid released from dehydration of phengite and zoisite leads to partial melting of eclogite and formation of plagioclase reaction rim around kyanite at pressures of 1.5--2.0 GPa and temperatures of 800--850℃; （3） phengite reacted with omphacite and quartz and produced oligoclase, kyanite and melt at elevated temperatures. Oligoclase is the primary reaction product produced by partial melting of phengite in the eclogite; and （4） the dehydration melting of phengite-bearing eclogite at pressures of 1.5--3.0 GPa and temperatures ≥900℃ results in formation of garnets with higher molar fraction of pyrope （37.67 wt.%--45.94 wt.%）. Potassium feldspar and jadeite occur at P = 2.4--3.0 GPa and T≥900℃, indicating higher pressure and fluid-absent conditions. Our results constrain the solidus for dehydration melting of phengite-bearing eclogite at pressures of 1.5--3.0 GPa. Combining experi- mental results with field observations of partial melting in natural eclogites, we concluded that phengite-bearing eclogites from the Dabie-Sulu orogen were able to partially molten at P= 1.5--2.0 GPa and T= 800--850℃ during exhumation. The ultrahigh-high pressure eclogites would have experienced partial melting in association with metamorphic phase transformation under different fluid conditions.     

Coral reef ecosystems in the South China Sea as a source of atmospheric CO<Subscript>2</Subscript> in summer

Field measurements of air-sea CO2 exchange in three coral reef areas of the South China Sea (i.e. the Yongshu Reef atoll of the Nansha Islands, southern South China Sea (SCS); Yongxing Island of Xisha Islands, north-central SCS; and Luhuitou Fringing Reef in Sanya of Hainan Island, northern SCS) during the summers of 2008 and 2009 revealed that both air and surface seawater partial pressures of CO2 (pCO2) showed regular diurnal cycles. Minimum values occurred in the evening and maximum values in the morning. Air pCO2 in each of the three study areas showed small diurnal variations, while large diurnal variations were ob-served in seawater pCO2. The diurnal variation amplitude of seawater pCO2 was ~70 μmol mol–1 at the Yongshu Reef lagoon, 420–619 μmol mol–1 on the Yongxing Island reef flat, and 264–579 μmol mol–1 on the reef flat of the Luhuitou Fringing Reef, and 324–492 μmol mol–1 in an adjacent area just outside of this fringing reef. With respect to spatial relations, there were large differences in air-sea CO2 flux across the South China Sea (e.g. ~0.4 mmol CO2 m–2 d–1 at Yongshu Reef, ~4.7 mmol CO2 m–2 d–1 at Yongxing Island, and ~9.8 mmol CO2 m–2 d–1 at Luhuitou Fringing Reef). However, these positive values suggest that coral reef ecosystems of the SCS may be a net source of CO2 to the atmosphere. Additional analyses indicated that diurnal variations of surface seawater pCO2 in the shallow water reef flat are controlled mainly by biological metabolic processes, while those of deeper water lagoons and outer reef areas are regulated by both biological metabolism and hydrodynamic factors. Unlike the open ocean, inorganic metabolism plays a significant role in influencing seawater pCO2 variations in coral reef ecosystems.     

Relation between standard entropies of elements and electronic configurations

A close relationship has been found between the standard entropies of elements and their electronic configurations. Based on the positions of elements in the periodic table and the variation in the standard entropies of elements, the standard entropies of elements can be expressed as the sum of two functions:S ⁰=f(N) +f(E), whereS ⁰ is the standard entropy of an element,N the principal quantum number, andE the number of outermost electrons. And the specific formula isS ⁰ = 99.05N ^1/3 + [0.32(sp −4)⁴ -119.76] + [-56.56N ^1/3+ 0.70(sd ∼-7)² −42.12] + [−11.95 × 10⁻⁴(df-8)⁻⁴ -105.70], wheresp, sd, df are the numbers of the outermost electrons in thesp, sd, df regions of the periodic table, respectively. This formula helps reveal the essence of the standard entropies of elements and deepens our understanding of the thermodynamic characteristics of compounds.     

The fractal structures of the sample path of a general subordinator and the random re-orderings of the Cantor set

In this paper we have found a general subordinator,X, whose range up to time 1,X([0, 1)), has similar structure as random re-orderings of the Cantor setK(ω).X([0, 1)) andK(ω) have the same exact Hausdorff measure function and the integal test of packing measure. Supported by the National Natural Science Foundation, the Excellent Young Faculty Foundation of the State Education Commission of China and the Foundation for the Scholars Coming Back from Abroad Hu Xiaoyu: born in Apr. 1964, Professor     

Remote sensing of algal blooms using a turbidity-free function for near-infrared and red signals

HARMFUL ALGAL BLOOM ACTS UPON IMPORTANT ENVIRON-MENTAL PROBLEMS IN COASTAL WATERS.A UNIFIED AND IM-PLEMENTING METHOD FOR SURVEY AND MONITORING ALGALBLOOMS HAS BEEN DEVELOPED SINCE LAST DECADE.HOWEVER THERE IS A DATA GAP OF ABOUT TENS YEARS IN THE PERIOD W…     

Responses of woody plant root and xylem sap ATP to soil drying

The ATP in roots and xylem sap of two woody plant species, Platycladus orientalis and Acacia auriculiformis, subjected to rapid and slow soil drying has been determined employing firefly luciferase ATP assay method (sensitivity is at 10-12 mol ATP L-1). The ATP levels in the two species were 1.6 nmol·gDW-1 and 0.6 nmol·gDW-1 in roots, and 5.6 μmol·m-3 and 8 μmol ·m-3 in xylem sap, respectively. When plants of P. orientalis and A. auriculiformis were subjected to rapid soil drying, respectively, as soil water content (SWC) decreased from the normal level ( 0. 25 g ·gDW-1) to 0. 02 and 0. 06 g ·gDW-1, separately, plant water potential ( ) dropped to -4 and -3.2 MPa, differently, the ATP in roots decreased 99.7% and 42%, respectively . When the rapidly dried soil was watered for up to 6 d, SWC and were found to recover to their normal levels, but ATP content in roots of P. orientalis and A. auriculiformis recovered by 10% and 23%, respectively. When plants of P. orientalis and A. auriculiformis were subjected to slow soil drying, respectively, as SWC was found to decrease from the normal level to 0.1 and 0.13 g·gDW-1, separately, dropped to - 2.5 and - 2 MPa, differently, the ATP content in roots decreased 98% and 38%, respectively. When the slowly dried soil was watered for up to 8 d, ATP levels in roots of P. orientalis and A, auriculiformis recovered by 30% and 24%, respectively. However, ATP concentrations in xylem sap were not directly influenced by either SWC or . The plot dots of xylem sap ATP concentration versus root ATP content were found to be distributed diagonally. It is concluded that ATP in roots is more sensitive in response to SWC changes than that to and root-sourced ATP is a source of that in xylem sap. When plants are subjected to slow soil drying, the ATP levels in both root and xylem sap are higher than that to rapid soil drying.     

Observation of fiber ultrastructure of Ligon lintless mutant in upland cotton during fiber elongation

Lintless mutant is a super-short fiber mutanl in upland cotton only 4-8 mm in fiber length and also named Ligon cotton controlled by one dominant gene Li1. Fiber ultrastructure of the mutant (Li1) and its its wild (li1) in siti and in vitro was observed under an electron microscope to understand its cytological characteristics during the fiber cell elongation. The resulls showed that the mutant fiber in situ had thinner cytoplasm, more small vacuoles, less mitochondria, Golgi apparatus and endoplasmic reticula, and there were more starch granules which were free or packed in the amyloplast beside the cell wall than thai of wild type. It was indicated that scarcity of functional organelles and disability of transformation from starch to sugar might be associated with the tact that the mutant fiber cell was aborted too early to elongate into normal length. Mutant ovule in some media containing GA3 could produce a kind of huge callus that grew faster than normal ovules. The callus was covered with many white, loose, and semitransparent fiber-like cells that apt lo get off from ovule. These fiber-like cells were multicellular fibers generated by cell division and had black dots just like pigment glands in the stem and leaf of cotton. There were lots of micro-tubes beside cytoplasm membrane uf the multiecllular fiber, which were thought to be primary preparation for second wall deposition of multicellular fiber. It was indicated that GA3 might induce the expression of gene(s) that kept inactive in the field condition and then stimulate the original fiber cell in vitro to undergo divisionagain.     

Growth of the Huoersuosi anticline （north Tianshan Mountains） by limb rotation since the late Miocene

The Huoerguosi anticline, located in the north Tianshan Mountains piedmont fold-and-thrust belt, is a trending east-west fault-related fold. In the cross section along the Jingou River, its south limb is composed of the pre-growth strata of the Anjihaihe （E2.3a）, the Shawan （（E3-N1）s）, the Taxihe （N1t） and the lower part of the Dushanzi （N2d） Formations, trending east-west and dipping to south 55°, and the growth strata of the upper part of the Dushanzi （N2d） and Xiyu （（N2-Q1）x） Formations, dips of which decrease from 55° at the base of the growth strata to 47° at the bottom of the Xiyu （（N2-Q1）x） Formation to -0° at the top of the Xiyu （（N2-Q1）x） Formation. The strata at the north limb of the anticline are vertical or over-turned, and are cut by the breakthrough thrusts to result in the drag fold. In the depth, the anticline is symmetric, and its core comprises the Cretaceous and the Jurassic coal-bearing beds. In the seismic profile, the seismic reflectors of pre-growth strata at the south limb of the anticline dip to south constantly, and ones of the growth strata fan southward, whose dips decrease upward. The geometry of the south limb growth strata outcropped along the Jingou River valley and the deep structure of the anticline shown in the seismic profile indicate that the Huoerguosi anticline is a detachment fold anticline growing by limb rotation. Based on the growth model and magnetostratigraphic age, during the growing process of the Huoerguosi anticline, the average shortening rate absorbed by the south limb is -0.46 mm/a, and the average uplifting rate of the anticline is -0.86 mm/a which exceeds the average deposition rate, which is in accordance with the fact that the top of the anticline is intensely eroded. Considering symmetric geometry of the Huoerguosi anticline and ignoring the breakthrough thrusts, the shortening of the whole anticline should be more than -0.92 mm/a, doubling the shortening rate determined from the growth at the south limb.     

Characterization of a nitrogenase CrFe protein from a mutant UW3 of Azotobacter vinelandii grown on a Cr-containing medium

Biological nitrogen fixation is one of the most im-portant biochemical reactions in nature. It is catalyzed by an anaerobic metalloenzyme complex-nitrogenase. Three genetically distinct nitrogenase systems exist in Azotobacter vinelandii (A. vinelandii): Mo-containing nitrogenase, V-containing one and “Fe only” nitro-genase[1―4]. They are composed of two separable com-ponent proteins. For example, conventional Mo-con- taining nitrogenase is composed of component I (MoFe protein) and com…     

Preparation of (R)- and (S)-2-Allyl-1, 3, 2-dinaphtho (α, β) [d.f] dioxaborepin and their reactions with aldehydes

(R)- and(S)-2-Allyl-1,3,2-dinaphtho (α,β) [d.f] dioxaborepin ((R)-2 and(S)-2) have been first prepared by the reaction of(R)-(+)- or(S)-(−)-1, 1′-bi-2-naphthol and triallylborane in THF at room temperature, respectively.(S)-2 and(R)-2 are sensitive to moisture and oxygen in air and disproportionate easily to triallylborane and 1,1′-bi-2 naphthyl bis (1,1′-bi-2-naphtholborate) at ambient temperature. However, THF is a stabilizer for them. The reactions of(R)-2 or(S)-2 and some aliphetic or aromatic aldehydes in CH₂Cl₂ at −78°C for several hours afforded β-alkylenyl alcohols in up to 84.8%ee. Among them, optically active 1-(3, 5-dichlorophenyl)-3-butenol and 1-(2-methoxyphenyl)-3-butenol were first prepared Foundation item: Supported by the National Natural Science Foundation of China (29972033) Biography: Liu Dejun (1973), male, Ph. D, research direction: asymmetric synthesis     

Instability of relativistic electron beam with strong magnetic field

Stability criteria for a weak relativistic beam-plasma interaction in a strong magnetic field are found. Two beam modes occur,ω≈k _zC andω≈k _zC-ω_c. The dispersion equation of electrostatic two-stream is exactly solved with analytical method.     

Garnet Sm-Nd and U-Pb systems: A case study of a granulite from the European Variscan belt

This study presents zircon and garnet ages of a mafic granulite from the high-grade Variscan basement of the Black Forest, Germany and discuss isotope closure temperature of garnet Sm-Nd and U-Pb systems. Zircon grains yield 207Pb/206Pb ages between ～340 and ～414 Ma by the U-Pb and evaporation methods. In contract, garnet dating gives Sm-Nd and Pb-Pb isochron ages of (398±3) Ma and (411±14) Ma, respectively, which are older than most of zircon ages. These data imply that most of zircons lost radiogenic Pb, probably due to metamictization or recrystallisation during the granulite-facies metamorphism (～800℃) at ～340 Ma. Garnet Sm-Nd and U-Pb systems preserve chronological information of pro-grade metamorphism, probably profiting from a fluid-absence metamorphic environment. These results demonstrate that garnet mineral can be a better candidate than zircon mineral to date high-grade metamorphism by the U-Pb and Sm-Nd methods in some cases.     

Large selenium isotopic variations and its implication in the Yutangba Se deposit, Hubei Province, China

The selenium isotopic ratios have been measured in the Yutangba Se deposit, Hubei Province, China. The results show that the δ 82/76SeNIST values vary from -12.77‰ to 4.93‰, which is the largest Se iso- topic variation found so far in natural terrestrial samples. The sample Ytb-5 of high-selenium carbona-ceous shale has the lightest Se isotopic composition with a δ 82/76SeNIST value of -12.77‰. On the basis of variations of Se isotope in the deposit along with other geological and geochemical evidence, the "redox model" is suggested to favor the explanation of the occurrence of native Se in the deposit. The application to the Yutangba Se deposit with the discovery of large Se isotopic fractionation for natural samples indicates the potential of Se isotope as a new geochemical tracer.     

A matrix version of the Wielandt inequality and its application to statistics

Suppose that A is an n × n positive definite Hemitain matrix. Let X and Y be n × p and n × q matrices (p+ q≤n), such that X* Y = 0. The following inequality is proved X*AY( Y* AY)-Y Y*AX≤( (λ1-λn)/(λ1+λn))2 X*AX, where λ1 and λn are respectively the largest and smallest eigenvalues of A, and M- stands for a generalized inverse of M. This inequality is an extension of the well-known Wielandt inequality in which both X and Y are vectors. The inequality is utilized to obtain some interesting inequalities about covari-ance matrix and various correlation coefficients including the canonical correlation, multiple and simple correlation.     

A Note on the Prime Spectrums of Character Rings of Finite Groups

0Introduction LetGbeafinitegroupoforder|G|=g,andletR(G)denotethecharacterringofG,whichisgeneratedbyalltheirreduciblecomplexcharactersofG.LetZbetherationalintegerringandNthesetofnatural numbers,andletZ[ω]betheintegralextensiongeneratedbyaprimitiveg throotωofunity.SupposethatSisasubringof thealgebraicnumberfieldsuchthatZ[ω]S.πisasetofra tionalprimenumbersdefinedasfollowsπ={p｜pisarationalprimenumbersuchthatp-1S}.Definition1WecallthataconjugacyclassCofthefinite groupGisaπregularconju…     

Additive characters and orthogonal systems of polynomials in several indeterminates over residue class rings

Letm, n andk be positive integers, m> 1 andk≤ n. Let ‰ _m =‰m‰ denote the residue class ring modulom. Let ‰ _m denote the group of additive characters of ‰ _m denote the identity of ‰ _m . A necessary and sufficient condition for the systemf ₁,...,f _k ∈ ‰ _m [x ₁, ...,x _m ] to be orthogonal is given: for all additive characters ψ₁, ..., ψ _k ∈ ‰ _m with ψ_i,≠x₀ forsomei, . As corollaries, the result of Shiue-Sun-Zhang and the result of Sun are obtained.