90 resultados para Sr^2
Resumo:
The whole rock K-Ar ages of basalts from the South China Sea basin vary from 3.8 to 7.9 Ma, which suggest that intra-plate volcanism after the cessation of spreading of the South China Sea (SCS) is comparable to that in adjacent regions around the SCS, i.e., Leiqiong Peninsula, northern margin of the SCS, Indochina block, and so on. Based on detailed petrographic studies, we selected many fresh basaltic rocks and measured their major element, trace element, and Sr-Nd-Pb isotope compositions. Geochemical characteristics of major element and trace element show that these basaltic rocks belong to alkali basalt magma series, and are similar to OIB-type basalt. The extent of partial melting of mantle rock in source region is very low, and magma may experience crystallization differentiation and cumulation during the ascent to or storing in the high-level magma chamber. Sr-Nd-Pb isotopic data of these basaltic rocks imply an inhomogeneous mantle below the South China Sea. The nature of magma origin has a two end-member mixing model, one is EM2 (Enriched Mantle 2) which may be originated from mantle plume, the other is DMM (Depleted MORB Mantle). Pb isotopic characteristics show the Dupal anomaly in the South China Sea, and combined with newly found Dupal anomaly at Gakkel ridge in Arctic Ocean, this implies that Dupal anomaly is not only limited to South Hemisphere. In variation diagrams among Sr, Nd and Pb, the origin nature of mantle below the SCS is similar to those below Leiqiong peninsula, northern margin of the SCS and Indochina peninsula, and is different from those below north and northeast China. This study provides geochemical constraints on Hainan mantle plume.
Resumo:
RFID,EPC Class-1 Gen-2,(SR),SR,,,
Resumo:
To investigate the changes in the chemical weathering intensity of dust source region in Asia continent, ~(87)Sr/~(86)Sr ratios of acid-washed residues from the loess deposits in China and Tajikistan were analyzed, respectively. The results and conclusions are listed as below. 1. The oscillation of ~(87)Sr/~(86)Sr ratios of acid-insoluble residues in the Chinese Loess Plateau was mainly attributed to the chemical weathering intensity of the source region and the grain size. Counteracted the effect of particle size, the calibrated 87Sr/S6Sr ratio can be used as a proxy for the chemical weathering intensity of the source region. 2. The Sr/ Sr ratios of red clay-loess sequence from the Loess Plateau indicate that the chemical weathering intensity of the dust source region between 7.0 and 2.6 Ma is stronger than that in the Quaternary period. This also suggests a general decline in chemical weathering intensity of the source region from 2.6 Ma to the present. Such pattern is more remarkable since 1.0 Ma BP. 3. The ~(87)Sr/~(86)Sr ratios of the Tajik loess during 0.8-1.8 Ma is much more higher than those from 0.8 Ma to the present. This implies that the chemical weathering intensity of the source region in Central Asia is much stronger during 0.8-1.8 Ma than the period since 0.8 Ma. 4. The record of Sr isotope ratios from both sections shows an accelerating course of aridity of the Asian dust source region over the Quaternary period.
Resumo:
Sr/CaMg/CaSr/CaMg/Ca^87Sr/^86Sr28Sr/CaMg/Ca^87Sr/^86Sr0.97-0.94Ma0.96-0.95MaSr/CaMg/CaSr/CaMg/Ca^87Sr/^86Sr28Sr/CaMg/Ca^87Sr/^86Sr0.97-0.94Ma0.96-0.95Ma
Resumo:
22SrpH56(pH=453)Ca^2+57moll^-1(12-164moll^-1)64-87Mg^2+13moll^-1(54moll^-1)Ca^2+Mg^2+78-96K^+11moll^-1(244moll^-1)Na^+4moll^-1(18moll^-1)SO4^2-941moll^-1(34279moll^-1)28-94NO3^-48moll^-1(1-252moll^-1)SO4^2-NO3^-SO4^2=NO3^-77-99Cl^-20moll^1(1128moll^-1)Sr002-O33moll^-1^87Sr^86Sr(0707934-0709080)^87Sr^86Sr0707820-0709078Sr
Resumo:
,,AlNa2OK2O;.,,,NbTaTi;,La/YbN5.010.911.212.0.SrNdt,^87Sr/^86Sri0.705770.707574,Ndt-8.1-1.8,^87Sr/^86Sri0.705470.70552,Ndt-0.20.6.SrNd,.SrNd,,,,.,.,,.
Resumo:
3ZnPb25%35%PhSCOHSrN^206Pb^204Pb^207Pb^204Pb^206Pb^204Pb1825118530156631585538.48739433^208Pb^204Pb-^206Pb^204PbN^14S1091741317^13C-21-35, ^18O16.8186DFI-50-60200^18OH2O708.8^13C^13DFI^87Sr^86Sr07140717^87Sr^86Sr0.70830709307106^87Sr^86Sr^87Sr^86Sr.
Resumo:
Sm-NdSrSmNd036063^143Nd/^144Nd051211051288^147Sm^144Nd-^143Nd^144NdNdt-102-147-379001NdNdSr^87St^86Sr07304-07329^87SrSrSr-NdSr
Resumo:
COSr^13 CPDB-54-14^18 OSMOW61139^87Sr^86Sr0710107230^13 CPDB0206^18 OSMOW194215^87Sr^86Sr0710100501CO2SrSrSr
Resumo:
SrSr070766-070932(070672070821)(070441070638)^87SrSrSrSrSr;(FSb)Sr
Resumo:
COSr^13CPDB-0720^18OSMOW186- 196Sr26458174gg5656gg87SrS6Sr0709607097^13 CPDB-39-21^18OSMOW115153Sr Rr7852563gg1571gg^87 Sr^85 Sr07109-0715407141COSrH2CO3^87 Sr-.
