Partition-coordinated control of soil and water loss for chestnut forests in the Yanshan Mountain Region,China     

Xinhui Ding  Guangquan Liu  Xiaoying Liu  Yongsheng Xie  Zhichun Yue 《国际泥沙研究》2019,34(1):58-64

Soil erosion from chestnut forests is one of the most important factors causing land degradation in the Yanshan Mountain Region. A 2-year field study was done to compare the effects on erosion of a control plot (CP), a repaired and maintained horizontal ditch built with an engineering baffle every 6?m (MP 1), and a repaired and maintained horizontal ditch built with an engineering baffle every 8?m (MP 2). The results showed that the slope runoff of chestnut forests was influenced by rainfall characteristic factors. No single rainfall characteristic factor showed dominance for hill slope runoff. The runoff reduction effect of the partition-coordinated erosion control measures (MP 1 and MP 2) was substantial for chestnut forests under high rainfall intensity conditions. However, the runoff reduction efficiency was higher under the conditions of heavy rainfall and low average rainfall intensity than for storms with higher intensity and lower total rainfall. The reduction effect of the partition-coordinated erosion control measures on the runoff and sediment yield of chestnut forest slopes was MP 2 > MP 1 > CP. The runoff reduction rate and erosion reduction rate of MP 2 reached 61.70% and 97.41%, respectively, and that for MP 1 was 54.15% and 85.31%, respectively. Therefore, after a comprehensive comparison, MP 2 was determined to be more effective for soil erosion control for a sloping chestnut forest.  相似文献   

湘西北地区五峰-龙马溪组页岩物质组成特征与页岩气潜力分析          下载免费PDF全文

高莉  王宗秀  梁明亮  张林炎  李会军  李春麟  高万里 《中国地质》2019,46(2):407-418

为了研究湘西北龙山-永顺地区上奥陶统五峰组-下志留统龙马溪组页岩气资源勘探潜力，利用野外典型露头地质剖面资料，通过对典型剖面页岩样品的系统观测、采样、利用有机地球化学和矿物组成特征研究，评价研究区目标地层页岩的成烃成藏物质基础。研究结果表明，研究区五峰-龙马溪组黑色泥页岩普遍具有有机碳含量高、残留可溶有机质氯仿沥青"A"低、生烃潜能S₁+S₂指数略低。分子生物标志化合物分析显示，正构烷烃无明显奇偶优势，受一定程度的微生物降解影响，多表现为双峰型（C₁₈/C₂₅），∑C₂₁-/∑C₂₂₊值为0.45~1.11，显示轻烃组分缺失，重烃组分占绝对优势；Pr/Ph值范围在0.27~0.44，具有植烷优势，显示原始有机质发育于较强还原沉积环境。烃源岩样品饱和烃组成相对丰度五环三萜烷 > 三环萜烷 > 四环萜烷，三环萜烷中C₂₁、C₂₃、C₂₄呈倒V字形分布，Ts/Tm为0.39~0.66。C₂₇规则甾烷含量略大于C₂₉规则甾烷，显示沉积母质以浮游生物及海洋型自养菌为主，亦含有部分藻类为主的有机质输入。镜质组反射率Ro均在2.57%~3.01%，普遍小于3%，已经达到了过成熟阶段。全岩矿物组成成分分析显示，页岩中脆性矿物为主要组成成分，其次为黏土矿物。综合页岩有机和无机物质组成分析结果，提出研究区湘西北五峰-龙马溪组页岩具备页岩气成烃成藏的物质条件基础，有机质含量高、热演化程度适中、脆性和吸附性较好，为深入开展页岩气勘探目标区优选奠定了工作基础。  相似文献   

江西冷水坑矿床含矿花岗斑岩的Sr-Nd及锆石Hf-O同位素研究          下载免费PDF全文

龚雪婧  曾建辉  曹殿华 《中国地质》2019,46(4):818-831

江西冷水坑铅锌矿床是武夷成矿带北段的典型矿床，矿区内含矿花岗斑岩锆石U-Pb年龄为（162.0±2.0）Ma，岩浆分异程度较高，具有高SiO₂（69.46%~75.52%）、高K₂O（K₂O/Na₂O>3.22）、强过铝质（ASI=1.20~1.96）的特征。岩体发育较明显的Eu负异常，富集强不相容元素Rb、Th、U，而亏损高场强元素Ba、Sr、Nb、Ta、P、Ti。全岩同位素测试结果显示，冷水坑含矿花岗斑岩具有极高的⁸⁷Sr/⁸⁶Sr初始比值（0.74005~0.76518）与低的ε_Nd值（-11.48~-10.78），锆石Hf-O同位素测定值变化范围较小，¹⁷⁶Hf/¹⁷⁷Hf介于0.282317~0.282460，具有负的ε_Hf（t）值（-12.39~-7.62）和相对较高的δ¹⁸O值（7.23‰~8.81‰），指示岩浆主要来自于成熟地壳，可能起源于北武夷地区变质基底，源岩为基底变质岩，这可能与古太平洋板块俯冲形成的挤压背景下的地壳熔融有关。  相似文献   

赣东北枣林碧玄岩地球化学特征及成因          下载免费PDF全文

吴美仁  陈祺  王先广  陈国华  万浩章  严加永  欧阳永棚 《中国地质》2019,46(4):850-860

在中国东部赣东北朱溪矿集区枣林地段发现两条新生代碧玄岩岩脉。地球化学研究表明该碧玄岩具有低SiO₂（41.08%~42.94%），高Mg^#（0.61~0.65），高TiO₂（2.19%~2.43%），高Na₂O+K₂O（4.95%~6.30%）的特点。∑REE为299.16×10^-6~375.00×10^-6，LREE/HREE比值为5.45~6.71，表明轻稀土富集，δEu为0.88~0.94，具微弱Eu负异常。微量元素特征表现出较高Ni、Cr、Sc含量，蛛网图显示明显富集Nb、Ta、Th、Zr等元素，亏损Ba、Ti、K、P等。主量元素相关图解和不相容元素比值显示岩石在演化过程中未遭受地壳混染。综合分析岩石微量元素数据及相关图解，文章认为由于太平洋板块俯冲，导致软流圈地幔携带碳酸盐熔体上涌与岩石圈地幔相互作用，使得0.2%~0.5%石榴石相二辉橄榄岩与0.5%~1%尖晶石相二辉橄榄岩发生部分熔融，生成碧玄岩原始岩浆。  相似文献   

高密度电阻率法与CSAMT法在江西会昌县坝背地热勘查中的综合探测          下载免费PDF全文

付光明  黄进调  刘阳  李晓兵  陈国玉  黄艺 《中国地质》2019,46(4):927-936

地热资源是一种绿色低碳、极具竞争力的可再生能源。江西省会昌县坝背地区断裂构造密集，地热异常广泛发育。为了查明勘查区各断裂构造的产状、规模及深部变化特征，为寻找地热水钻孔布置提供依据，项目组首先在已知温泉位置布置3条高密度试验测线，接着在已知温泉位置以南布置4条高密度测线，然后在高密度电阻率法资料初步解释成果的基础上再施工可控源音频大地电磁测深法（CSAMT），得出其中两条深大断裂是温泉主要的导水导热构造、断裂深切至基底界面、基底界面起伏明显的结论。同时圈定了4个低阻异常区，其中低阻异常范围最大的区域长约1000 m，宽约240 m，高约200 m，是含水最为有利区域，亦是寻找地热水的直接依据，建议在其正上方布设钻孔进行验证，孔深约800 m，满足深大断裂和基底对低阻区的深度控制。  相似文献   

新疆库车蒸发岩盆地两种不同类型卤水的发现及其对铜富集的意义          下载免费PDF全文

鲁宽  徐海明  伯英  王军  曹养同 《中国地质》2019,46(5):1247-1248

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Using Red Edge Position Shift to Monitor Grassland Grazing Intensity in Inner Mongolia     

Jiajia Zheng  Fei Li  Xin Du 《Journal of the Indian Society of Remote Sensing》2018,46(1):81-88

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Extraction of Alteration Mineral Information from Moderate Remote Sensing Images Using MPS Method     

Kefa Zhou  Nannan Zhang 《Journal of the Indian Society of Remote Sensing》2018,46(1):89-96

Although alteration minerals related to metallogenesis is very important in mineral exploration, information of alteration mineral is weakly expressed in remote sensing imagery, which is often subject to interfering noise and sometimes limited in spectral and spatial resolutions. Because of easy access, moderate images are the main sources of alteration mineral information. Therefore, it is very important to develop alteration mineral information extraction methods from remote sensing images. In this paper, a combined method based on Mask, principal component analysis (PCA) and support vector machine method (SVM) was used to extract alteration mineral information from Enhanced thematic mapper plus remote sensing data with limited spectral and spatial resolutions. First, a mask image of the remote sensing imagery was created to remove interference information such as vegetation, shadow and water. Then, PCA was employed to collect sample data relating to iron, argillic, and carbonatization alteration. Finally, SVM was used to deal with alteration anomaly and build a feature extraction model of high accuracy. The Mask-PCA-SVM model is used to extract alteration mineral information from remote sensing images of Hatu area, Xinjiang Uygur Autonomous Regions, China. The results show that the new methods proposed in this paper can coincide well with known deposits occurrences, rate reached 86.51%. While, the consistent rate with known deposits of the ratio model, PCA model and Spectral angle mapper model were only 3.37, 65.08 and 69.05% respectively. This suggests that the proposed model can find the actual distribution of mineral deposits more effectively by reducing interference to a greater degree.  相似文献   

The Extraction of Urban Surface Water from Hyperspectral Data Based on Spectral Indices     

Jiawei Yang  Chengyu Liu  Rong Shu  Feng Xie 《Journal of the Indian Society of Remote Sensing》2018,46(11):1749-1759

To prevent confusion between water and buildings in the extraction of urban surface water from hyperspectral data, we analyzed the spectra of shadows and water in hyperspectral images, and proposed an anti-shadow water extraction method. This method first uses the normalized difference vegetation index (NDVI) for initial water extraction, then uses the height of the reflectance peak at 588 nm to eliminate the shadow of buildings. The method was validated by two hyperspectral datacubes, which were obtained for Jiaxing City and Zhoushan City in Zhejiang Province, China. Compared to the common spectral indices used to extract a water body, such as the NDVI, normalized difference water index, hyperspectral difference water index, and index of water index, the proposed method could effectively eliminate the shadow of buildings. The commission error reduced from more than 40% to about 15%, and the Kappa coefficient was increased from 60 and 70% to over 80% for the two datacubes. This indicated that the proposed method can inhibit the shadow of buildings and does not have a regional dependence.  相似文献   

Concentrations of metallic elements in long-range-transported aerosols measured simultaneously at three coastal sites in China and Japan     

Kojiro?ShimadaEmail author  Xiaoyang?Yang  Yushi?Araki  Ayako?Yoshino  Akinori?Takami  Xuan?Chen  Fan?Meng  Shiro?Hatakeyama 《Journal of Atmospheric Chemistry》2018,75(2):123-139

To determine the effects of long-range transport of aerosols from an upwind area in East Asia to a downwind area in Japan, we chemically analyzed aerosols collected simultaneously on Tuoji Island (Shandong Province, China), Fukue Island (Nagasaki Prefecture, Japan), and Cape Hedo (Okinawa Prefecture, Japan). We focused on changes in the metallic composition of PM_2.5 aerosols during long-range transport. The average mass concentrations of PM_2.5 at the three sites decreased in the order Tuoji Island > Fukue Island ≈ Cape Hedo (48.3 ± 4.5, 13.9 ± 1.5, and 13.2 ± 0.9 μg/m³, respectively). The fraction of coarse particles in total suspended particles estimated by (1–PM_2.5/TSP) was highest on Cape Hedo, indicating that the contribution of sea salts was increased by long-range transport of the aerosols over the ocean. Enrichment factor analysis revealed that at all three sites, Al, K, Ca, Mn, Fe, Co, Sr, and Ba originated from soil; whereas Cr, Ni, Cu, Zn, As, Mo, Ag, Cd, Sn, Sb, Tl, and P appeared to be of anthropogenic origin. Na was the most abundant element on Cape Hedo, indicating the addition of sea salts during aerosol transport. The V concentration was highest at Fukue Island, which was ascribed to V emission from ships. Sixty-one percent of the V on Fukue Island and 62% of the V on Cape Hedo were determined to have originated from ships, implicating of data obtained on dates during which backward trajectory analysis indicated that the same air mass passed over Tuoji Island, Fukue Island, and Cape Hedo in that order.  相似文献