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1.
琥珀是由古代植物代谢产生的树脂聚合物形成的化石。琥珀中的有机质保存环境稳定、封闭,能很好地记载其形成时期的古植物和古环境等信息。本次研究运用气象色谱质谱联用仪(GC-MS)和元素分析稳定同位素质谱仪(EA-IRMS)等测试方法,研究了沈北煤田煤中琥珀的有机地球化学组成、稳定同位素和化合物单体碳同位素特征。结果表明,琥珀中的饱和烃以二萜化合物为主(占73.45%),芳香烃以松香烷型化合物为主(56.17%);高含量的贝壳杉烷、雪松烷、扁枝烷和松香烷型化合物指示琥珀来源于松柏类植物,且以柏科植物为主。沈北琥珀的δ13C值为-22.8‰ ~ -21.2‰,与同时期其他地区琥珀的δ13C值相似;氢同位素变化范围较小(-297.2‰ ~ -276.0‰),氧同位素值为17.4‰ ~ 31.6‰。琥珀的稳定同位素组成(碳、氢和氧)进一步证明琥珀来源于裸子植物。琥珀的δ13C值主要与其形成时的全球气温变化和大气组成有关。沈北琥珀的氢和氧同位素组成主要受植物种类(松柏类)以及植物生长的局部气温和降水条件有关。琥珀稳定碳同位素有望成为研究古气候和古大气组成的良好载体,琥珀的氢和氧同位素可以反映形成时期的古环境条件,但仍需进一步深入研究。  相似文献   
2.
Geomagnetism and Aeronomy - Based on an analysis of data from the midlatitude ionospheric stations, it is found that the P = 0.5(F1 + F81) index is an optimal solar-activity index for the daily...  相似文献   
3.
Gorelits  O. V.  Kryjov  V. N.  Rakcheeva  E. A.  Ermakova  G. S. 《Water Resources》2022,49(5):836-844
Water Resources - Based on 1965–2020 series we have shown relationships between the features of the water runoff of the spring flood in mouths of large rivers of North-Eastern Europe and the...  相似文献   
4.
Marine ferromanganese nodules and crusts containing Mn, Cu, Ni and Co in the most promising resource-grade concentrations and quantities, together with Fe and Zn (all elements of biogeochemical importance) are found far from land on the deep seafloor of the Pacific Ocean. The biogeochemical, chemical and physical mechanisms contributing to their formation, distribution, abundance and – for these six elements – variability in their concentrations in these deposits, are the main focus of the present review. The mechanisms addressed include biological productivity, sedimentation types and rates, bottom water characteristics, the Calcium Carbonate Compensation Depth, the depth and intensity of the oxygen minimum zone, and biogeochemical characteristics of the six focal elements. Particular attention is given to comparisons between the deposits found in the north and the south Pacific, in order to present an overarching view of our current understanding of the mechanisms that apply to both nodules and crusts in both oceanic hemispheres, including examination of the possible existence of a marine ferromanganese oxide continuum. The renewed interest in the commercial exploitation of these deposits has stimulated a welcome increase in scientific research that is essential to informing the public discourse on seabed mining. We briefly reflect on the work addressed in this review in that context.  相似文献   
5.
Roy  R.  Kuttippurath  J.  Lefèvre  F.  Raj  S.  Kumar  P. 《Theoretical and Applied Climatology》2022,149(1-2):119-130
Theoretical and Applied Climatology - Sudden stratospheric warmings (SSWs) are associated with rapid rise in temperature in a short period of time in the polar vortex and reversal of the zonal...  相似文献   
6.
Geomagnetism and Aeronomy - Analysis of the features of the form of low solar cycles 23 and 24 for the solar-activity indices (F is the solar radio flux at a wavelength of 10.7 cm, Rz and Ri are...  相似文献   
7.
Geomagnetism and Aeronomy - A comparative analysis of the correlation between the number of strong (magnitude M ≥ 5.0), crustal (hypocenter depth 0 ≤ h ≤ 60 km) earthquakes per...  相似文献   
8.
Geomagnetism and Aeronomy - Fluxes in flares are studied in soft X-ray (SXR) and extreme ultraviolet (EUV) bands based on data from GOES, the Solar Dynamics Observatory (SDO), and the Thermosphere,...  相似文献   
9.
Many of the world's major aquifers are under severe stress as a result of intensive pumping to support irrigated agriculture and provide drinking water supplies for millions. The question of what the future holds for these aquifers is one of global importance. Without better information about subsurface conditions, it will be difficult to reliably assess an aquifer's response to management actions and climatic stresses. One important but underutilized source of information is the data from monitoring well networks that provide near-continuous records of water levels through time. Most organizations running these networks are, by necessity, primarily focused on network maintenance. The result is that relatively little attention is given to interpretation of the acquired hydrographs. However, embedded in those hydrographs is valuable information about subsurface conditions and aquifer responses to natural and anthropogenic stresses. We demonstrate the range of insights that can be gleaned from such hydrographs using data from the High Plains aquifer index well network of the Kansas Geological Survey. We show how information about an aquifer's hydraulic state and lateral extent, the nature of recharge, the hydraulic connection to the aquifer and nearby pumping wells, and the expected response to conservation-based pumping reductions can be extracted from these hydrographs. The value of this information is dependent on accurate water-level measurements; errors in those measurements can make it difficult to fully exploit the insights that water-well hydrographs can provide. We therefore conclude by presenting measures that can help reduce the potential for such errors.  相似文献   
10.
Otyukova  N. G. 《Water Resources》2021,48(3):449-458
Water Resources - Indirect chemical characteristics of organic matter concentration were determined in small streams in especially protected natural territories, including 15 tributaries of Lake...  相似文献   
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