郧西县庹家湾黄土剖面色度参数特征及其古气候重建

发布时间：2018-07-24 17:28

【摘要】：通过对湖北省郧西县庹家湾黄土剖面的色度参数分析,并结合磁化率、粒度、铷锶比(Rb/Sr)指标揭示汉江上游地区风成黄土的色度特征及其与气候变化的关系。应用X-rite VS450型分光测色仪对庹家湾黄土剖面色度参数进行了测量。结果表明:庹家湾黄土剖面红度a*的变化与沉积物氧化铁含量呈显著正相关,平均值由高到低依次为S_0(6.34)MS(5.52)L_t(5.18)L_0(4.98)L_1(4.82)T_(1-al_2)(3.66);亮度L*的变化与氧化铁含量和有机质含量均呈负相关,其中氧化铁含量对L*的影响更大,L*在黄土层出现了峰值;色调角h*在古土壤层呈现低值(68.64°),黄土层呈现高值,a*/b*与h*特征相反,在古土壤呈现高值(0.39),黄土层呈现低值;其中在马兰黄土L_1中存在两层弱古土壤层L_1-S_2、L_1-S_1,其色度参数特征较L_1具有较高的a*值和a*/b*值及较低的L*值和h*。黄度b*指示该区域气候变化有一定的局限性,h*、a*/b*、L*和a*均可作为良好的气候替代指标,a*值和a*/b*值越大指示气候越暖湿,成壤作用越强,L*值和h*越大指示气候越冷干,成壤作用越弱。h*、a*/b*、L*和a*共同记录了该地区晚更新世以来气候经历了晚更新世末期的干冷、全新世早期逐渐回暖、全新世中期的温暖湿润、全新世晚期气候逐渐干冷,在马兰黄土形成时期,气候出现了短暂的温暖湿润期(27.5~21.5ka B.P.)。
[Abstract]:Based on the analysis of chromaticity parameters of Tuojiawan loess profile in Yunxi County, Hubei Province, combined with magnetic susceptibility, particle size and rubidium strontium ratio (Rb/Sr), the chromaticity characteristics of wind-formed loess in the upper reaches of the Hanjiang River and its relationship with climate change are revealed. The colorimetric parameters of Tuojiawan loess profile were measured by X-rite VS450 spectrometer. The results showed that the change of red degree a * in Tuo Jiawan loess profile was positively correlated with the iron oxide content in sediment, and the average value from high to low was SSP 0 (6.34) MS (5.52) LSP _ 0 (4.98) L _ 1 (4.82) T _ (1-al_2) (3.66), and the change of luminance L * was negatively correlated with the content of iron oxide and organic matter. The effect of Fe _ 2O _ 3 on L ~ (*) content is greater than that of Fe ~ (2 +) content in the loess layer, and the hue angle (H _ (*) is low (68.64 掳) in paleosol layer, whereas the yellow soil layer is characterized by a high value (0.39) and a low value (H ~ (*). There are two layers of weak paleosol in Ma Lan loess L _ S _ 1, and its chromaticity parameter characteristic is higher a * value, a / b * value and lower L * value and hu value than that of L _ S _ 1, and it has two layers of weak paleosol layer L _ s _ 1-S _ 2 / L _ S _ (1), and its chromaticity parameter characteristic is higher than that of L _ s _ 1. The yellowness b * indicates that there are some limitations in climate change in the region. Both L* and a * can be used as good climate substitution indicators. The greater the value of a * and a / b *, the warmer and wetter the climate is, and the stronger the role of earth-forming is, the greater the value of L* and the greater the value of h* indicates the colder and drier the climate. The weaker the earth-forming process is, the weaker the climate in this area has been recorded since the late Pleistocene, the warming in the early Holocene, the warm and humid in the middle of the Holocene, and the dry and cold climate in the late Holocene. During the formation of Ma Lan loess, the climate experienced a brief warm and humid period (27.5~21.5ka B.P.).
【作者单位】：陕西师范大学旅游与环境学院地理学国家级实验教学示范中心;
【基金】：国家自然科学基金项目(42171108,41371029,41471071) 国家社会科学基金项目(14BZS070) 中央高校基本科研项目(GK201601006)
【分类号】：S151.9;P532

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