稳定碳同位素在湘中千佛洞上覆土壤-滴水-现代沉积物的迁移特征研究

通过对2021年1月~2022年10月期间,湘中千佛洞洞外大气-上覆土壤气-洞穴空气二氧化碳含量（pCO₂）及其碳同位素（δ¹³C_CO2）、8个洞穴水体（4个滴水、3个地下河水、1个池水）溶解无机碳同位素（δ¹³C_DIC）以及洞穴现代沉积物碳同位素（δ¹³C）的连续监测,初步获得了监测时段内千佛洞岩溶系统中δ¹³C在垂直方向上运移的变化特征,并得到以下3点主要认识：1）千佛洞上覆土壤气、洞穴空气pCO₂及δ¹³C_CO2表现出相似的季节变化特征,夏季pCO₂偏高,δ¹³C_CO2偏轻,冬季则相反。降水量和温度是土壤pCO₂及δ¹³C_CO2变化的主要影响因素;2）千佛洞洞穴水体δ¹³C_DIC值呈现显著的季节变化规律,夏季偏轻,冬季偏重,表明土壤pCO₂及δ¹³C_CO2对其影响较大,说明该洞洞穴水体δ¹³C_DIC可以较好地响应外界环境变化。此外,4个滴水点δ¹³C_DIC值在变幅和绝对值之间存在一定差异,这可能是受到不同滴水点的运移路径和滴水速率等因素的影响;3）千佛洞现代沉积物δ¹³C也表现出明显的季节变化特征,说明该洞现代沉积物δ¹³C可以较好地继承滴水中的δ¹³C_DIC信号。千佛洞的初步观测结果为利用该洞穴或者临近区域洞穴沉积物开展古气候重建提供了借鉴和参照。

     

陕西靖边大路坬黄土地层的划分

黄何中游南部和中部地区的黄土以往研究的比较多, 飞但对北部地区的黄土一直研究很少。由于黄河中游北部地区地处黄土与其它第四纪沉积物的过渡带, 地及活动频繁, 因, 而, 研究黄河中游北部地区的黄土, 不仅在第四纪地质、地貌、新构造运动以及古地理、古气候理论研究方面有很大的意义。     

Replacing fishmeal with soybean meal affects survival,antioxidant capacity,intestinal microbiota,and mRNA expression of TOR and S6K1 in Macrobrachium rosenbergii

Using alternative plant-derived dietary protein to replace fishmeal, combined with practical evaluation indexes, is a recent focus for aquaculture practices. An 8-week feeding experiment with giant freshwater prawn Macrobrachium rosenbergii post-larvae was conducted to determine the effects of replacing fishmeal(FM) with soybean meal in the feed, in terms of growth performance, antioxidant capacity, intestinal microbiota, and m RNA expression of target of rapamycin(TOR) and ribosomal protein S6 ...     

Longitudinal genetic analysis of growth-related traits in red swamp crayfish Procambarus clarkii(Girard)

The red swamp crayfish, Procambarus clarkii, is an economically important species especially in China. Their exoskeleton places serious constraints on growth and culture management. Their growth is achieved through intermittent molting/ecdysis. The longitudinal genetic dynamics for growth-related traits at different ecdysial points in P. clarkii has been unclear to date. In this study, conditional genetic analysis was carried out for growth-related traits(body weight, body length, chela length, ...     

热惯量法在监测土壤表层水分变化中的研究

利用遥感方法监测一定层水深土壤水分变化，关键是建立卫星数据与地表水热变化关系，该文地遥感定量反演土壤水热变化的数值模拟系统及热惯量在其边界，初始条件确定中所起的作用进行的简述，并介绍了热惯量法求解表层水分含量的发展概况，为进一步提高定量化监测方法的地必琢计算精度，该文发展了地表能量平均方程的一种新的化简方法，经过这样的处理，可从遥感图象数据直接得到真实热惯量值，进而得到土壤水分含量分布，通过野外实     

Geology and geochemistry of the Changba SEDEX Pb-Zn deposit,Qinling orogenic belt,China

The Changba Pb-Zn SEDEX deposit occurs in the Middle Devonian sequence of the Anjiaca Formation of the Western Qinling Hercynian Orogen in the Gansu Province, China. The Changba-II orebody is hosted in biotite quartz schist and is the largest of 143 stratiform orebodies that are hosted either in biotite quartz schist or marble. The Changba-II comprises two types of mineralization: a bedded facies and an underlying breccia lens. The bedded section exhibits three sulfide sub-facies zoned from bottom to top: 1) banded sphalerite intercalated with quartz albitite; 2) interbedded massive pyrite and sphalerite ore; and 3) banded sphalerite ore intercalated with banded baritite. Major metallic minerals are sphalerite, pyrite, galena, with minor arsenopyrite, pyrrhotite, boulangerite, and rare chalcopyrite. The bedded sulfides are underlain by a lens of brecciated and albitized biotite-quartz schists cemented by sulfides and tourmaline.Massive and bedded sulfide ³⁴S values range from 8.1 to 29.3, whereas barite ³⁴S values range from 20.8 to 31.5. Disseminated pyrite in footwall schists has ³⁴S values ranging from 8.1 to 10.6, and increase to values ranging from 11.1 to 14.7 in the hangingwall. The lower ³⁴S values for massive and bedded sulfides are interpreted to be derived from progressive bacterial sulfate reduction (BSR) of Devonian seawater in a sulfate-restricted sub-basin. The higher ³⁴S values for massive and bedded sulfides could be a product of quantitative BSR but this is incompatible with barite being more abundant above the bedded sulfides. Instead, it is more likely that thermochemical sulfate reduction of seawater sulfate or of evaporite was the source of heavy hydrothermal sulfur. Heavy hydrothermal sulfur was injected into a sulfate-restricted sub-basin where it mixed with low ³⁴S BSR sulfide to form the massive and bedded sulfides. The REE patterns of sulfide layers and associated quartz albitite and baritite are similar to those of the host biotite quartz schists, suggesting that the hydrothermal fluids leached REE from the underlying rocks. Pb isotope ratios in galena form an array between the Upper Crust and the Mantle reservoir curves, which indicates that the lead is derived from upper crustal rocks comprising mafic igneous units. The Sr⁸⁷/Sr⁸⁶ ratio of 0.7101 for carbonate within the sulfide layers also suggests that Sr is derived from the mixing of Sr leached from upper crustal rocks with Middle Devonian seawater Sr. A Rb-Sr isochron age of 389.4 ± 6.4 Ma for sulfide layers and the interbedded hydrothermal sediments is consistent with the age of host Mid-Devonian strata. Ar³⁹/Ar⁴⁰ plateau age at 352.8 ± 3.5 Ma and Ar³⁹-Ar⁴⁰ isochron age of 346.6 ± 6.4 Ma for albite in the quartz albitite intercalated with sulfide layers indicate either albite formation after the sulfides or thermal resetting of the Rb-Sr system at about 350 Ma, the age of collision between the North China and Yangtze cratons.Editorial handling: E. Frimmel     

Application of RgMap system on digital regional geological survey

Digital geological mapping fundamentally broke through the traditional working pattern,successfully carried out the geological mapping digitalization.By using the RGMAP system to field digital geological mapping,the authors summarized the method of work and the work flow of the RGMAPGIS during the field geological survey.First,we prepared material,set up the PRB gallery,then put the geographic base map under the background maplayer and organizing the field hand map,forming the field factual datum map.At last,the geological space database is formed.     

Comparative Study of Magmatism in East Pacific Rise Versus Nearby Seamounts: Constraints on Magma Supply and Thermal Structure Beneath Mid‐ocean Ridge

Major elements of 2202 basalts from the East Pacific Rise (EPR) and 888 basalts from near-EPR seamounts are used to investigate their differences in magma crystallization pressures and mantle melting conditions. Crystallization pressure calculation from basalts with 5.0wt%相似文献   

湖南1∶25万怀化幅区域地质调查主要成果及新认识

1∶25万怀化幅图区主要位于扬子陆块东南缘,自西向东划分为武陵断弯褶皱带、沅麻盆地、雪峰冲断带及邵阳坳褶带4个构造单元。通过此次调查研究,取得了以下主要进展及成果:基本查明了区内板溪群与高涧群的相变关系及界线;提出了南华纪长安期沿雪峰山与涟邵盆地的结合带存在一凹陷槽;对区内岩浆岩侵入时代和期次做了详细的划分,建立了岩浆演化序列;结合同位素年龄数据,系统地对白马山—龙山复式岩基带及其周边的中酸性—酸性花岗岩体侵入时代、火山岩系的喷发时代进行了统一厘定;查明了雪峰造山带的构造变形特征、构造样式以及沅麻盆地的构造特征和形成演化过程。     

陕西蓝田灞源一带金矿地质特征及成因浅析

本文通过分析灞源地区的赋矿地层、岩浆岩及断裂构造与金矿形成的关系，查明了控制金矿形成与分布的地质条件，并重点论述了金矿床的产出、矿化类型、围岩蚀变和含金矿物等主要地质特征。最后根据矿床地球化学特征综合分析阐明本区金矿床的岩浆热液成因。