A New LA‐ICP‐MS Method for Ti in Quartz: Implications and Application to High Pressure Rutile‐Quartz Veins from the Czech Erzgebirge          下载免费PDF全文

Alicia M. Cruz‐Uribe  Regina Mertz‐Kraus  Thomas Zack  Maureen D. Feineman  Glenn Woods  Dorrit E. Jacob 《Geostandards and Geoanalytical Research》2017,41(1):29-40

Experimental determination of the pressure and temperature controls on Ti solubility in quartz provides a calibration of the Ti‐in‐quartz (TitaniQ) geothermometer applicable to geological conditions up to ~ 20 kbar. We present a new method for determining ⁴⁸Ti mass fractions in quartz by LA‐ICP‐MS at the 1 μg g^?1 level, relevant to quartz in HP‐LT terranes. We suggest that natural quartz such as the low‐CL rims of the Bishop Tuff quartz (determined by EPMA; 41 ± 2 μg g^?1 Ti, 2s) is more suitable than NIST reference glasses as a reference material for low Ti mass fractions because matrix effects are limited, Ca isobaric interferences are avoided, and polyatomic interferences at mass 48 are insignificant, thus allowing for the use of ⁴⁸Ti as a normalising mass. Average titanium mass fraction from thirty‐three analyses of low temperature quartz from the Czech Erzgebirge is 0.9 ± 0.2 μg g^?1 (2s) using ⁴⁸Ti as a normalising mass and Bishop Tuff quartz rims as a reference material. The 2s average analytical uncertainty for individual analyses of ⁴⁸Ti is 8% for 50 μm spots and 7% for 100 μm spots, which offers much greater accuracy than the 21–41% uncertainty (2s) incurred from using ⁴⁹Ti as an analyte.  相似文献   

Fluorescence as a Tool for Tracing the Organic Contamination from Pulp Mill Effluents in Surface Waters     

Eduarda B. H. Santos  Olga M. S. Filipe  Regina M. B. O. Duarte  Helena Pinto  Armando C. Duarte 《洁净——土壤、空气、水》2001,28(7):364-371

Three‐dimensional fluorescence spectra of water samples from an eucalyptus bleached kraft pulp mill and from a river, upstream and downstream of the discharge of the effluent, revealed the existence of a peak at δ_exc = 280 nm and δ_em = 340 nm Δδ = 60 nm), characteristic of effluentπs organic matter. Humic substances were isolated from the effluent by sequential adsorption onto resins XAD‐8 and XAD‐4 in series. Their synchronous fluorescence spectra with Δδ = 60 nm do also exhibit an intense signal at δ_exc = 280 nm (≈ 300 nm in the humic acid fraction). The peak is absent in the spectra of humic substances isolated from a non‐polluted site of the river, but it is clearly seen in the spectra of the humic substances from a site downstream of the discharge of the effluent. Synchronous fluorescence spectra (Δδ = 60 nm) of water samples from the river and its lagoon were recorded and revealed to be an easy and fast way of tracing the organic contamination from the effluent.  相似文献   

Relative equilibria of the restricted three-body problem in curved spaces     

Regina Martínez  Carles Simó 《Celestial Mechanics and Dynamical Astronomy》2017,128(2-3):221-259

We use a formulation of the N-body problem in spaces of constant Gaussian curvature, \({\kappa }\in \mathbb {R}\), as widely used by A. Borisov, F. Diacu and their coworkers. We consider the restricted three-body problem in \(\mathbb {S}^2\) with arbitrary \({\kappa }>0\) (resp. \(\mathbb {H}^2\) with arbitrary \({\kappa }<0\)) in a formulation also valid for the case \({\kappa }=0\). For concreteness when \({\kappa }>0\) we restrict the study to the case of the three bodies at the upper hemisphere, to be denoted as \(\mathbb {S}^2_+\). The main goal is to obtain the totality of relative equilibria as depending on the parameters \({\kappa }\) and the mass ratio \(\mu \). Several general results concerning relative equilibria and its stability properties are proved analytically. The study is completed numerically using continuation from the \({\kappa }=0\) case and from other limit cases. In particular both bifurcations and spectral stability are also studied. The \(\mathbb {H}^2\) case is similar, in some sense, to the planar one, but in the \(\mathbb {S}^2_+\) case many differences have been found. Some surprising phenomena, like the coexistence of many triangular-like solutions for some values \(({\kappa },\mu )\) and many stability changes will be discussed.  相似文献   

Vertical deformation partitioning across a collapsing large and hot orogen     

F. A. Temporim  Ricardo Ivan Ferreirae da Trindade  Marcos Egydio-Silva  Tiago Valim Angelo  Eric Tohver  Caroline Cibele Soares  Lucas Pequeno Gouvêa  Julio Cesar Mendes  Silvia Regina Medeiros  Antônio Carlos Pedrosa-Soares  Gabriel Gomes Silva 《地学学报》2023,35(1):23-31

Featuring 3 000-km-long large and hot orogen, the Mantiqueira Province provides a rare opportunity to study the process of gravitational collapse at mid to deep crustal levels. Distinct but contemporary (~500 Ma) post-collisional intrusions show structures and anisotropy of magnetic susceptibility (AMS) fabrics related to their emplacements, recording different flow patterns. In southern deep-seated intrusions, ellipsoidal-shaped roots with gabbroic-to-hybrid cores surrounded by granitic rocks show concentric patterns of AMS fabrics that cut across the NE-trending regional foliation. In contrast, northern intrusions, exposed as the upper sections of batholith-size bodies of coarse-grained granite emplaced at the shallow to mid-crust, show general NS-trending magnetic fabrics roughly parallel to strike of the orogen and the regional foliation of host rocks. These contrasting magnetic patterns from shallow to deeper crust suggest vertical magma migration from the overthickened orogenic core to be emplaced across its thinner stretched flanks during the gravitational collapse of the orogenic edifice.  相似文献