Helium is a scarce strategic resource. Currently, all economically valuable helium resources are found in natural gas reservoirs. Owing to helium’s different formation and migration processes compared to natural gas’s, the traditional method of collecting wellhead gas to detect helium concentration may miss helium-rich layers in the vertical direction, which will not only cause the waste of helium resources, but also restrict the study of helium migration and accumulation mechanisms. To solve this problem, we designed a helium detector based on a quadrupole mass spectrometer. Through the combination of different inlet valves, we avoided gas mixing between different vertical layers during the inlet process and realized high-spatial-resolution helium concentration detection. We applied the helium detector to the Dongsheng gas field in the northern Ordos Basin, and the instrumental detection results were consistent with the laboratory analysis results of the wellhead gas, which demonstrated the stability of the helium detector in the field environment and the reliability of the data. Meanwhile, the results showed that the distribution of helium in the plane is highly heterogeneous, and the natural gas dessert layers and the helium dessert layers do not coincide in the vertical direction. In addition, we found a good correlation between helium and hydrogen concentrations. Combining our results with previous data, we propose a hydrogen–helium migration and accumulation model, which enriches the understanding of helium accumulation mechanisms and provides a basis for future helium resource exploration.
21 February 2025 in Journal of Geophysical Research: Planets
The Chang'e‐5 landing site provides an important window into the Moon's late Eratosthenian period of volcanism at ∼2 Ga. Clarifying the Moon's history of volcanic activity using radioisotopic dating assists investigations of the evolution of the lunar surface as well as the Moon's internal dynamics. Recent chronological investigations of Chang'e‐5 basalts produced ages spanning ∼100 Ma, thereby inhibiting interpretation of the duration of volcanism recorded in the returned samples. We used microcomputed tomography and Back‐Scatter Electron imaging to characterize the structure and morphology of nine Chang'e‐5 basalt clasts. Several basalt clasts lack shock features and are interpreted to have not been significantly thermally disturbed. 40Ar/39Ar incremental heating produced well defined plateaus for four sub‐split samples that give a weighted mean age of 2,021 ± 17 Ma (2σ). These are among the youngest mare basalts to be dated thus far by the 40Ar/39Ar method and, when combined with most of the published Pb‐Pb ages for Chang'e‐5 basalts, define a single episode of mare volcanism at ∼2,021 Ma.
The nitrogen isotopic compositions of lunar soil have important implications for the sources of lunar volatiles and even the evolution of the moon. At present, the research on the lunar nitrogen isotopic compositions is mainly based on the lunar meteorites and the samples brought back by the Apollo and Luna missions. However, volatiles adsorbed on the surface of the lunar soil may be lost due to changes in temperature and pressure, as well as vibration and shock effects when the sample is returned. At the same time, in the case of low N content in the sample, since N is the main component of the earth’s atmosphere, it is easily affected by the atmosphere during the analysis process. Therefore, in situ nitrogen isotopic analysis of lunar soil on orbit is necessary to avoid the problems mentioned above and is one of the primary science goals for the Lunar Soil Volatile Measuring instrument on Chang’e-7 spacecraft. After the nitrogen purification procedure, the volatiles in lunar soil that are released through single-step or stepped heating techniques diffuse to the quadrupole mass spectrometer to obtain the N contents and isotopic compositions of the lunar soil. This paper introduces the ground test for N isotopic analysis of lunar soil in orbit according to the Lunar Soil Volatile Measuring Instrument. After long-term repeated measurements, the background and CO-corrected Air-STD 14N/15N ratio is 268.986 ± 4.310 (1SD, n = 35), and the overall reproducibility of measurements is 1.6%. The accuracy of N isotopic compositions is calculated to be better than 5%, which can distinguish different sources of N components in lunar soil.
30 January 2026 in Geochimica et Cosmochimica Acta