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1.
湖南主要土壤酸沉降敏感性初步研究 总被引：2，自引：0，他引：2
通过对湖南省主要土壤类型在模拟酸雨条件的敏感性大小进行研究，根据酸害阈值、酸害变化率等敏感性指标，对土壤敏感性进行比较发现，在酸雨pH值大于4．5时，处于土壤酸雨缓冲范围，而当酸雨pH值低于3．5或3时，土壤的pH值变化相当明显。不同土壤母质对酸雨的敏感性表现为：第四纪红土红壤＞砂岩红壤＞花岗岩红壤＞紫色砂页岩红壤；由于垂直地域分异作用，山地红壤的敏感生较大，其次为山地黄棕壤，山地黄壤为不敏感土壤；另外不同土层的敏感差异不明显，受耕作过的土壤酸缓冲性能明显增强。 相似文献
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不同地质背景下发育的土壤及其对物种多样性的影响 总被引：3，自引：0，他引：3
以重庆金佛山地区为例,分析土壤基本理化性质与成土母质和植被的关系,并对石灰岩和砂页岩地区的生物多样性及其与土壤基本理化性质的关系进行了探讨。结果表明,成土母质对土壤基本理化性质的影响主要体现在钙镁总量上,但这种影响随着土壤发育的成熟和植被正向演替的进展逐渐减弱;不同母质地区的物种多样性指数均与土壤钙镁含量呈明显的负相关,在土壤发育和生态恢复初期,土壤中较高的钙镁含量对物种多样性有一定的限制作用;石灰岩地区的物种多样性与土壤因子的关系更为复杂,导致群落的不稳定性增强。 相似文献
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位于北京西南57km的牛口峪水库建于奥陶系喀斯特化石灰岩之上。沿着区域性断层强烈的喀斯特作用使得水库发生严重渗漏,并污染了地下水体。根据水文地质条件和对水库渗漏的研究,可得出如下结论:1.牛口峪水库地区石灰岩含水体的特征主要受到牛口峪坡立谷演化过程的控制。地表下5—10m是喀斯特强烈发育带,但是充填在喀斯特裂隙中的红粘土降低了石灰岩含水体的导水性和储水能力。深于地表以下10m处,主要为裂隙含水体。石灰岩中的溶蚀裂隙和小管道沿着F_2断层发育。2.石灰岩含水体中存在着受库水影响较大的浅循环潜水流和深循环裂隙扩散流。3.牛14孔和牛11孔分属于两个水文地质单元,库水向牛11孔方向渗漏的可能性很小。4.库水主要通过表层灰岩体结构遭受破坏的石灰岩裂隙进行渗漏。最主要的渗漏带是牛14孔—牛10孔—马刨泉带,其次是水库—牛7孔—马刨泉带和四副坝坝基渗漏。主坝坝基深层石灰岩体中的渗漏是存在的,但不严重。 相似文献
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发育于中寒武统厚层状鲕状灰岩和薄层泥质灰岩中的河北临城崆山白云洞是一个上下三层 ,总长 50 0m、面积 4 2 0 0m2 的小型旅游洞穴。洞内碳酸钙景观极其丰富 ,尤其是石幔、卷曲石、石葡萄。白云洞老洞积石已发生了强烈的风化 ,洞积石已变得疏松 ,易折断和掉块。在老洞积石强烈风化处或在风化洞积石上 ,发育了新的洞积石。在白云洞所在的崆山山脊上保留了三十万年前形成的大型石笋基群和洞穴石葡萄、石瘤和钙板等。根据洞穴中的裂隙网和迷宫洞道、洞穴太湖石、地下湖及地下水补排特征 ,作者认为白云洞是喀斯特地下水对石灰岩泡蚀作用的产物。 相似文献
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洞穴滴水水文化学特征及石漠化效应--以贵州石将军洞为例 总被引：3，自引：0，他引：3
利用洞穴指标体系研究地表石漠化演变处于理论萌芽阶段.据此,通过对发育在强度石漠化条件下的石将军洞穴滴水滴率、pH值及温度进行为期1 a的动态监测,在分析其特征空间、时间变化规律基础的上,初步探索其石漠化效应.研究结果表明:受石漠化发育引起的地表植被破坏严重、土层稀薄影响,上覆顶板对水分的赋存主要靠基岩来完成,基岩愈厚,洞穴滴水滴率、pH 值与温度变率愈小,因此表现出越靠近洞口受外界影响越强烈、变幅越大的特征;同时,强度石漠化条件下,土壤中可利用的CO2较少,使得洞穴滴水pH 值显示了雨季时值较高、旱季时值较低的反常特征. 相似文献
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福建武夷山风景名胜区及其附近地区的地貌研究 总被引：2，自引：0，他引：2
武夷山风景名胜区及其附近地区由花岗岩、火山熔岩、变质岩和砂页岩等构成的中山、低山占最大面积.最高海拔约1800m,在海拔350～1200m,有7级剥蚀夷平面,形态有山顶缓坡型、山坡肩膀型、谷底裂点型(占绝大多数).丹霞地貌的顶面坡以圆弧形为主,陡崖坡有罕见的切层洞穴群和最大的晒布岩,崖麓缓坡多由红层组成.河流纵谷常沿着NNE走向较软的中生界砂页岩发育,断层谷断续长数十公里;横谷常沿着NWW的走向节理发育.据6个TL年龄认定河流阶地的沉积年代:第一级阶地Q3 ,第二级阶地Q2或Q2为主,第三级阶地Q2. 相似文献
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滂汪山水泥用石灰岩矿床为沉积型矿床,属中型偏小水泥灰岩矿床,矿区内构造、岩浆岩活动不发育,对矿体影响较小。矿体主要赋存在徐庄组上部、张夏组及崮山组中,自然类型主要为鲕状灰岩、斑纹状灰岩和薄层状灰岩。矿石氧化钙的含量比较稳定,而且含量较高,而氧化镁的含量,在矿层走向、倾向和垂深上都不稳定,而且变化较大,其他有害元素都不高。本区石灰岩矿主要含矿层位是寒武系徐庄组、张夏组和崮山组灰岩,主要出露在萧县复式背斜两翼,为下一步找矿提供了方向。 相似文献
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《山地学报》2015,(1)
茶树具有喜酸聚铝特性,而酸性条件下土壤中的磷很容易被固定。为了弄清茶树根际土壤磷的吸附过程与作用机理,采用外源磷吸附培养方法,研究了不同母质、不同种植年限茶树根际土壤磷的吸附过程与动力学,并用最小二乘法进行Langmuir等温吸附方程拟合磷吸附动力学曲线,探讨了茶树根际土壤的磷吸附特征。结果表明:茶树根际土壤与非根际土壤磷的吸附过程与动力学有明显的差异。与非根际土壤的相比,茶树根际土壤最大吸附量(Xm)值低56 mg/kg,但是最大缓冲容量(MBC)高2.60,磷吸附饱和度(DPS)高1.44,表明根际土壤磷吸附力显著低于非根际土壤,而磷生物有效性高于非根际土壤。3种成土母质发育的茶园根际土壤磷吸附能力强弱依次为第四纪红色粘土花岗岩风化物板页岩风化物。随着种植年限的延长,根际土壤磷吸附能力特征值Xm和MBC有所降低,而DPS有所增加。第四纪红色粘土、花岗岩风化物和板页岩风化物3种母质发育的茶树根际土壤DPS值依次提高了0.83、2.83和3.51,而Xm依次降低了91 mg/kg,131 mg/kg和61 mg/kg。 相似文献
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湄洲岛系福建莆田市湄洲湾口花岗岩大陆岛，处平潭—南澳断裂带中段，北东向高角度倾滑正断层组合，控制了岛屿南、北两个平行地垒中夹一地堑平原的地形特征。全岛有3级海阶发育，海拔依序为40～35、30～10、10m，依晚更新世海阶序列与隆升率关系对比基图叠合法推估，其生成年代分别为103ka、83ka和6ka，整体基盘的平均隆升速率为0.48mm/a。岛上出露开元、宫下、北埭和鹅尾山4条北东向平行正断层，形成地垒、地堑、直线状断崖、反斜崖、断层鞍部及断侧丘、断层池等相关断层变位地形。 相似文献
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通过对广州夏茅村岩溶塌陷进行地质勘察,系统探讨了当地的地质环境条件、岩溶塌陷的灾害特征、岩溶发育条件和岩溶塌陷的形成原因。结果表明,区内第四系覆盖土层厚度大且分布不均,土洞大量发育,隐伏可溶岩的富水性好,溶洞发育;同时,覆盖层内的松散岩类孔隙水与下伏灰岩裂隙溶洞水之间的水力联系密切,含水砂层内地下水位的改变会直接引起下伏灰岩裂隙溶洞水的水位波动,构成岩溶塌陷的水动力因素;钻孔桩施工时钻孔揭穿覆盖层内土洞顶部的黏性土层盖板,造成盖板上部的细砂及淤泥流入土洞,是岩溶塌陷的直接触发因素。在此基础上,提出建立岩溶分布区的地下水动态长期监测网,对岩溶塌陷地段进行灌浆处理,是根治夏茅村岩溶塌陷的主要有效途径。 相似文献
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《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(3-4):171-175
Laminated silts and clays occur throughout the 400 m vertical range of CastJeguard Cave, an alpine cave in the Rocky Mountains of Alberta, Canada. Coarser sediments have accumulated at the base of phreatic lifting chimneys. Presently a lower level cave, Castleguard II is hydrologically active. The fine sediments are believed to have resulted from turbid water backing up from Castleguard II into the cave with a loss of the coarser fraction in the process. At present the water emerging from Castleguard II is clear, and during glacial maxima the system would be inactive. It is hypothesised that turbid water to furnish the sediments would only be available during glacial minima in the environment of Castleguard. 相似文献
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Brujas Cave, in the Southern Andean Range, is a well-known endokarstic site in Argentina. However, the origin and evolution of this cave system are poorly known. Based on morphological cave features as well as characteristics of cave deposits, we propose a meteogene drawdown cave genesis, including a change from phreatic to vadose conditions related to the high rate of fluvial downcutting in the area. During the vadose period, various cave-related deposits, including authogenic calcite and gypsum speleothems, allogenic volcanic ash and external tufas were deposited. Gypsum crusts are the oldest cave deposits identified (90.2–64.3 ky BP). Their origin, deduced from isotopic characteristics (∂34S=9.6‰), is related to the oxidation of pyrite contained in the Jurassic limestone bedrock as well as the dissolution of overlying Jurassic–Triassic evaporite formations. Gypsum crust deposition is associated with evaporation of water flowing and seeping into the cave during arid environmental conditions. Calcite deposits precipitated from flowing water under equilibrium conditions represent the main speleothem growth period (67.6–34 ky BP in age). Their stable isotope values (∂13C=−3‰ to −5‰ and ∂18O=−9‰ to −11‰) may indicate slightly humid and warm conditions related to the regional Minchin lacustrine phase and global oxygen isotope stage 3. Following this stage, a seismic event is evidenced by accumulations of broken stalactites. Seepage calcite speleothems covering cave walls were deposited under disequilibrium conditions by evaporation, probably during Holocene time. Finally, another more recent gypsum deposition period represented by gypsum balls has been differentiated. Micromorphological as well as isotopic (∂34S=5.6‰) data indicate that these gypsum forms are related to cyclic processes (solution–deposition) from water seeping into the cave under arid conditions. In addition, intense volcanic activity in the area during Holocene time is deduced from allogenic volcanic ash and lapilli located mainly at the entrance cave. At present, limited hydrological activity is observed in the cave and small tufa deposits at karstic discharge points are evidenced. We conclude that the geomorphological evolution of Brujas Cave was controlled by climatic changes (wet and dry stages) under semiarid environmental conditions in a very active tectonic and volcanic setting during Late Quaternary time. 相似文献
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广东英德宝晶宫CO2浓度的时空变化特征 总被引：4，自引：0，他引：4
于2011年12月至2013年4月每月一次对广东英德宝晶宫溶洞洞穴空气CO2浓度进行监测,结果显示洞穴空气CO2浓度存在明显的空间变化和季节变化。洞内空气CO2浓度在201×10-6?3 450×10-6之间变化,年平均值为1 018×10-6。在空间上,越靠近洞口或者通风效应越强的地方洞穴空气CO2浓度越低。在季节变化上,表现为洞穴空气CO2浓度在夏半年（5-10月）高而在冬半年（11-4月）低的特点。洞穴空气CO2浓度变化主要受洞穴通风效应和气候变化导致的植被呼吸作用和土壤微生物活动变化的影响。此外,宝晶宫特殊的洞穴结构及游客等因素也对该溶洞CO2浓度变化形成了一定的影响。 相似文献
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川东北楼房洞洞穴环境时空变化与影响因素 总被引：4，自引：0，他引：4
基于2011年8月―2012年6月的实地监测数据,文章报道了川东北楼房洞溶洞系统气温、相对湿度（RH）、CO2体积分数、水体电导率（EC）和pH值等为期近1年的监测结果,并对其影响因素进行了分析。结果显示楼房洞洞穴系统环境存在明显的空间变化和季节变化：1）洞穴内的气温变化幅度比洞穴外小,洞穴内夏季气温比冬季高出3~5℃;2）在洞穴内,相对湿度在地下河附近小于在水池附近,显示了地下河对洞穴环境的显著影响;3）洞内监测点SLPB和QCMY处的相对湿度与空气温度出现明显相反的变化趋势,反映主要受气温控制的特点;4）雨季期间SLPB、QCMY和LZLY处的CO2体积分数出现峰值,是较强的生物呼吸作用、“泵”效应和较弱的通风效应等因素综合影响的结果;5）pH值的变化趋势在洞穴内外各监测点一致,原因可能是夏秋季节基岩溶蚀较强所致。6）洞内各监测点的EC值也是夏秋季节高于冬春季节,反映了气候变化导致的化学溶蚀作用可能是影响离子含量的主要因素。 相似文献
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洞穴次生化学沉积物与地质背景及洞穴环境的耦合关系——以广西巴马水晶宫为例 总被引：1，自引：0，他引：1
运用岩溶地貌及洞穴次生化学沉积物的成景机制和原理,结合动态耦合的方法和系统的观点,通过“洞穴”这一共同作用的对象,将洞穴的区域地质背景、洞穴外部环境、洞穴内部环境与洞穴次生化学沉积物成景过程进行有机联系,创立某一洞穴次生化学沉积物成景耦合系统,概括其内涵、特征和意义。同时通过对广西巴马水晶宫区域地质背景、洞穴外部环境、洞穴内部环境等系统分析和研究,全面系统探讨水晶宫洞穴次生化学沉积物的成景耦合过程,并按不同时期区域构造运动的程度及洞穴次生化学沉积物的形成特征,将该成景耦合过程划分为4个可往复循环的阶段：① 区域构造平稳前期—洞穴次生化学沉积物形成发育阶段;② 区域构造平稳中期—洞穴次生化学沉积物大规模发育阶段;③ 区域构造平稳后期—洞穴次生化学沉积物缓慢或停止发育阶段;④ 区域间歇性构造运动—洞穴次生化学沉积物崩塌阶段。 相似文献
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The origin of the sediments located in the Naracoorte Caves (South Australia) was investigated via the analysis of strontium isotope ratios (87Sr/86Sr), elemental geochemistry, and mineralogy. Sedimentary deposits located in Robertson, Wet, Blanche and several other chambers in Victoria Cave are all variable mixes of fine sand and coarse silts, which display similar and consistent strontium isotope ratios (0.717–0.725). This suggests that over the 400 ka time frame that these deposits span there has been minimal variation in the source of the clastic sediments. Increased strontium concentrations for these cave sediments correspond with increasing silt content, yet there is no correlation between 87Sr/86Sr ratios and silt content. This implies that the silt-sized component of the sediments is the main contributor of strontium to the cave sediments. Comparisons of 87Sr/86Sr with regional surficial deposits show a significant correlation between the cave sediments (avg: 0.7228; n = 27), the fine silt lunettes of the Bool Lagoon area (avg: 0.7224; n = 4), the sandy A horizons of the Coonawarra Red Brown Earths (RBEs; avg: 0.726; n = 5), and Holocene age podsolic sand deposits (0.723). These data suggest that there has been substantial flux from this group of deposits to the caves, as would be expected considering prevailing winds. This relationship is further supported by a strong correlation between many trace elements, including Ti, Zr, Ce, and Y; however, variations in clay mineralogy suggest that the fine silt-dominated lunettes and Padthaway RBEs were not significant contributors to the cave deposits. Hence, the detritus entering the caves was more than likely from areas proximal to the cave entrance and was dominated by medium grain-sized materials. Major regional deposits, including the coarser-grained, calcite-rich Bridgewater Formation sands, basalts from the lower SE, Padthaway Horst granites, Gambier limestone, and metamorphics from the Adelaide geosyncline show minimal correlation in 87Sr/86Sr ratios, elemental geochemistry, and mineralogy with the cave sediments, and are discounted as significant sources. In comparison, 87Sr/86Sr ratios for the Coorong silty sands (0.717–0.724), Lower Murray sands (0.727–0.730), and the medium size silt component of the Murray–Darling River system (0.71–0.72), compare favourably with the cave sediments. This relationship is further supported by similarities in elemental chemistry and mineralogy. Thus, much of the strontium-rich silt that is now located in the Naracoorte Cave sediments likely originated from the Murray–Darling basin. Over time, this material has been transported to the SE of South Australia, where it mixed with the medium sand component of the regressive dune ridge sequence, locally derived organic matter, limestone fragments, and fossil material to produce the unique deposits that we see evident in many of the chambers of the Naracoorte Cave system today. 相似文献
19.
Morphometry and distribution of isolated caves as a guide for phreatic and confined paleohydrological conditions 总被引：1，自引：0，他引：1
Isolated caves are a special cave type common in most karst terrains, formed by prolonged slow water flow where aggressivity is locally boosted. The morphometry and distribution of isolated caves are used here to reconstruct the paleohydrology of a karstic mountain range. Within a homogenous karstic rock sequence, two main types of isolated caves are distinguished, and each is associated with a special hydrogeologic setting: maze caves form by rising water in the confined zone of the aquifer, under the Mt. Scopus Group (Israel) confinement, while chamber caves are formed in phreatic conditions, apparently by lateral flow mixing with a vadose input from above. 相似文献
20.
《Basin Research》2018,30(Z1):1-14
The paleogeographic reconstruction of the Variscan Mountains during late Carboniferous‐Permian post‐orogenic extension remains poorly understood, owing to the subsequent erosion and/or burial of most associated sedimentary basins during the Mesozoic. The Graissessac‐Lodève Basin (southern France) preserves a thick and exceptionally complete record of continental sedimentation spanning late Carboniferous through late Permian time. This section records the localized tectonic and paleogeographic evolution of southern France in the context of the low‐latitude Variscan Belt of Western Europe. This study presents new detrital zircon and framework mineralogy data that address the provenance of siliciclastic strata exposed in the basin. The ages and compositions of units that constitute the Montagne Noire metamorphic core complex (west of the basin) dictate the detrital zircon age populations and sandstone compositions in Permian strata, recording rapid exhumation and unroofing of the Montagne Noire dome. Cambrian‐Archean zircons and metamorphic lithic‐rich compositions record derivation from recycled detritus of the earliest Paleozoic sedimentary cover and Neoproterozoic‐early Cambrian metasedimentary Schistes X, which formerly covered the Montagne Noire dome. Ordovician zircons and subarkosic framework compositions indicate erosion of orthogneiss units that formed a large part of the dome. The youngest zircon population (320–285 Ma) reflects derivation from late Carboniferous‐early Permian granite units in the axial zone of the Montagne Noire. This population appears first in the early Permian, persists throughout the Permian section and is accompanied by sandstone compositions dominated by feldspar, polycrystalline quartz and metamorphic lithic fragments. The most recent migmatization, magmatism and deformation occurred ca. 298 ± 2 Ma, at ca. 17 km depth (based on peak metamorphic conditions). Accordingly, these new provenance data, together with zircon fission‐track thermochronology, demonstrate that exhumation of the Montagne Noire core complex was rapid (1–17 mm year−1) and early (300–285 Ma), reflecting deep‐seated uplift in the southern Massif Central during post‐orogenic extension. 相似文献