Applications of stable water and carbon isotopes in watershed research: Weathering, carbon cycling, and water balances

Research on rivers has traditionally involved concentration and flux measurements to better understand weathering, transport and cycling of materials from land to ocean. As a relatively new tool, stable isotope measurements complement this type of research by providing an extra label to characterize origin of the transportedmaterial, its transfer mechanisms, and natural versus anthropogenic influences. These new stable isotope techniques are scalable across a wide range of geographic and temporal scales. This review focuses on three aspects of hydrological and geochemical river research that are of prime importance to the policy issues of climate change and include utilization of stable water and carbon isotopes: (i) silicate and carbonate weathering in river basins, (ii) the riverine carbon and oxygen cycles, and (iii) water balances at the catchment scale. Most studies at watershed scales currently focus on water and carbon balances but future applications hold promise to integrate sediment fluxes and turnover, ground and surface water interactions, as well as the understanding of contaminant sources and their effects in river systems

Particle species and energy dependencies of freeze-out parameters in high-energy proton-proton collisions

We used blast wave model with Tsallis statistics to analyze the experimental data measured by ALICE Collaboration in proton-proton collisions at Large Hadron Collider and extracted the related parameters (kinetic freeze-out temperature, transverse flow velocity and kinetic freeze-out volume of emission source) from transverse momentum spectra of the particles. We found that the kinetic freeze-out temperature and kinetic freeze-out volume are mass dependent. The former increase while the latter decrease with the particle mass which is the evidence of a mass as well as volume differential kinetic freeze-out scenario. Furthermore we extracted the mean transverse momentum and initial temperature by an indirect method and observed that they increase with mass of the particles. All the above discussed parameters are observed to increase with energy. Triton ($t$), hyper-triton (${^3_{\bar\Lambda} H}$) and helion (${^3 He}$) and their anti-matter are observed to freeze-out at the same time due to isospin symmetry.Comment: 13 pages, 5 figures, 1 tabl

Hydrochemistry and isotope systematics of the Indus River Basin.

This study presents a complementary geochemical and isotopic database (Ca2+, Mg2+, Na, K+, HCO 3--, SO42--, Cl --, trace elements and isotopes of H, O, C, S and Sr) for water samples from the Indus River Basin. These results, as well as published data for precipitation and river discharges were used to address the following aspects of the Indus River Basin: (1) water budget, annual solute fluxes, and denudation rate; (2) whether the summer monsoon or delayed runoff from winter precipitation dominates the discharge of the Indus and where does the water vapor for precipitation originate; (3) what are the sources and processes that control the distribution of solutes; (4) estimate the contribution of major ions to river water from carbonate and silicate weathering. The long-term mean annual precipitation water flux into the Indus River Basin is 398 km3. Based on major ion chemistry of rain and snow, the annual precipitation flux of Total Dissolved Solids (TDS) to the Indus River Basin is ∼ 844,400 tons. The Indus River annually transports ∼ 18 million tons of TDS that translates into a chemical denudation rate of 21 tons km--2. Oxygen and deuterium isotopes in the Indus River at Sukkur barrage for the Water Year March-94 to February-95 define the relationship deltaD = 7.5 (delta18O) + 10. This implies that despite aridity, significant evaporative enrichment is limited due to the short residence time of water and due to the minor contribution of runoff from the and middle and lower parts of the basin. Hydrochemistry of the Indus River is dominated by Ca2+ > Mg2+ > (Na+ +K+) and HCO 3-- > (SO42-- +Cl--) > Si. Sediment weathering is the dominant source for major cations, silicate weathering is important only locally. Three end member compositions control the Sr-isotope systematics of the Indus River. These are: (a) weathering of old silicate (silicic) rocks with high 87Sr/86Sr ratios and represented by rivers draining the Precambrian high grade metamorphic rocks of the Nanga Parbat-Haramosh massif and the "Central Crystallines" of the Higher Himalayas; (b) young silicate (mafic) rocks with the lowest 87Sr/ 86Sr ratios of all the Indus tributaries and represented by rivers draining mafic-ultramafic units of the Cretaceous Kohistan-Ladakh arcs; and (c) weathering of sedimentary carbonates with intermediate 87 Sr/86Sr, represented by the lowland tributaries draining sedimentary carbonates and shales of the West Pakistan Fold Belt. (Abstract shortened by UMI.

Excitation Function of Kinetic Freeze-Out Parameters at 6.3, 17.3, 31, 900 and 7000 GeV

The transverse momentum spectra of π+ (π−)(π++π−) at 6.3, 17.3, 31, 900 and 7000 GeV are analyzed by the blast-wave model with Tsallis statistics (TBW) in proton-proton collisions. We took the value of flow profile n0 = 1 and 2 in order to see the difference in the results of the extracted parameters in the two cases. Different rapidity slices at 31 GeV are also analyzed, and the values of the related parameters, such as kinetic freeze-out temperature, transverse flow velocity and kinetic freeze-out volume, are obtained. The above parameters rise with the increase of collision energy, while at 31 GeV, they decrease with increasing rapidity, except for the kinetic freeze-out volume, which increases. We also extracted the parameter q, which is an entropy-based parameter, and its rising trend is noticed with increasing collision energy, while at 31 GeV, no specific dependence of q is observed on rapidity. In addition, the multiplicity parameter N0 and mean transverse momentum are extracted, which increase with increasing collision energy and decrease with increasing rapidity. We notice that the kinetic freeze-out temperature and mean transverse momentum are slightly larger with n0 = 2, while the transverse flow velocity is larger in the case of n0 = 1, but the difference is very small and hence insignificant

Dependence of Freeze-Out Parameters on Collision Energies and Cross-Sections

We analyzed the transverse momentum spectra (pT) reported by the NA61/SHINE and NA49 experiments in inelastic proton–proton (pp) and central Lead–Lead (Pb−Pb), Argon–Scandium (Ar−Sc), and Beryllium–Beryllium (Be−Be) collisions with the Blast-wave model with Boltzmann–Gibbs (BWBG) statistics. The BGBW model was in good agreement with the experimental data. We were able to extract the transverse flow velocity (βT), the kinetic freeze-out temperature (T0), and the kinetic freeze-out volume (V) from the pT spectra using the BGBW model. Furthermore, we also obtained the initial temperature (Ti) and the mean transverse momentum (pT>) by the alternative method. We observed that T0 increases with increasing collision energy and collision cross-section, representing the colliding system’s size. The transverse flow velocity was observed to remain invariant with increasing collision energy, while it showed a random change with different collision cross-sections. In the same way, the kinetic freeze-out volume and mean transverse momentum increased with an increase in collision energy or collision cross-section. The same behavior was also seen in the freeze-out temperature, which increased with increasing collision cross-sections. At chemical freeze-out, we also determined both the chemical potential and temperature and compared these with the hadron resonance gas model (HRG) and different experimental data. We report that there is an excellent agreement with the HRG model and various experiments, which reveals the ability of the fit function to manifest features of the chemical freeze-out