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101.
以氯度作为保守性指数研究了杭州湾海区由于离子强度的变化水体中钾、钠、钙、镁、锶和硫酸根离子的保守性、非保守性行为,结果发现在测定相对误差分别为±0.2% ,±0.5% ,±0.5 % ,±0.2% ,±0 .5 % 时,钾、钠、镁、硫酸根在整个氯度范围内表现为保守性;锶在整个氯度范围内没有规律性的“迁入”或“迁出”行为;钙的不保守行为表现为在氯度6 ~8 之间有明显的“迁入”,其在低氯和高氯区则具有较好的保守性。并对此结果作了初步探讨。 相似文献
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103.
豫西荥巩——新密煤田太原组、山西组的沉积环境和聚煤规律 总被引:5,自引:0,他引:5
荥巩和新密煤田是豫西北部的两个相邻煤田。主要含煤地层为晚古生代晚石炭世太原组和早二叠世山西组,总厚100—150m;下石盒子组及晚二叠世的上石盒子组在本区仅偶含薄煤层。太原组位于含煤岩系最底部,为碳酸盐岩和碎屑岩交替沉积,灰岩形成于清澈、温暖、浅水的陆表海潮下环境,碎屑岩则为潮道和潮间带为主的潮道、潮坪沉积。太原组含有6—7层薄煤层,形成于咸水或半咸水的泥炭沼泽中。山西组几乎全由碎屑岩组成,下部发育本区的主要可采煤层二1煤。二1煤以下层位为潮坪和横向与之共生的潮道、潮沟及河口潮汐砂脊沉积,二1煤以上为河流作用为主的三角洲沉积,三角洲由北向南进积到半咸水的海湾中。二1煤形成于海退时期,它们堆积在滨海平原的淡水泥炭沼泽中,其厚度变化及发育程度主要受成煤前沉积环境控制,但在本区西部构造较复杂处,煤层厚度受后期构造影响较大。沉积环境对煤层原生厚度的影响主要表现在潮坪和废弃的潮道、潮沟、河口潮汐砂背沉积物之上,煤层发育好,而在二1煤之下有活动的潮道及河口潮汐砂脊发育时,煤层较薄或不发育。 相似文献
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为对辽东湾觉华岛附近海域海底工程地质环境进行系统评估,利用高分辨海底声学探测设备获取调查海区的精密水深地形数据,利用筛析法、激光粒度仪实验法确定沉积物类型及粒度参数特征,最终综合分析得到研究区海底地形地貌及沉积物分布特征。研究发现,目标海域测量水深介于4~22m之间,平均水深15m左右,海底地形平坦,整体表现为平缓的近岸缓坡,地貌以近岸粉砂淤泥质浅滩地貌为主,局部发育微型海底沙波;海底浅地层第一声学反射界面清楚连续,可全区追踪,穿透深度0.5~5m不等,沉积物厚度相对稳定;表层沉积物中值粒径普遍较小,沉积物类型东区以粉砂和砂质粉砂为主,西区以砂质粉砂为主;表层沉积物组分和粒度参数的空间变化规律较为复杂,分析认为其主要受到沉积物物源以及辽东湾内往复流、沿岸流的影响。。 相似文献
106.
Fluvial to bay sequence stratigraphy and seismic facies of the Cretaceous to Paleogene successions in the MITI Sanriku‐oki well and the vicinities,the Sanriku‐oki forearc basin,northeast Japan 下载免费PDF全文
This paper describes the significant depositional setting information derived from well and seismic survey data for the Upper Cretaceous to Lower Eocene forearc basin sediments in the central part of the Sanriku‐oki basin, which is regarded as a key area for elucidating the plate tectonic history of the Northeast Japan Arc. According to the results of well facies analysis utilizing cores, well logs and borehole images, the major depositional environments were of braided and meandering fluvial environments with sporadically intercalated marine incursion beds. Seismic facies, reflection terminations and isopach information provide the actual spatial distributions of fluvial channel zones flowing in a north–south trending direction. The transgression and regression cycles indicate that the Upper Cretaceous to Lower Eocene successions can be divided into thirteen depositional sequences (Sequences SrCr‐0 to SrCr‐5, and SrPg‐1 to SrPg‐7). These depositional sequences demonstrate three types of stacking patterns: Types A to C, each of which shows a succession mainly comprising a meandering fluvial system, a braided fluvial system with minor meandering aspects in the upper part, and major marine incursion beds in the middle part, respectively, although all show an overall transgressive to regressive succession. The Type C marine incursion beds characteristically comprise bay center and tidal‐dominated bay margin facies. Basin‐transecting long seismic sections demonstrate a roll up structure on the trench slope break (TSB) side of the basin. These facts suggest that during the Cretaceous to Eocene periods, the studied fluvial‐dominated forearc basin was sheltered by the uplifted TSB. The selective occurrences of the Type C sequences suggest that when a longer‐scale transgression occurred, especially in Santonian and early Campanian periods, a large bay basin was developed, creating accommodation space, which induced the deposition of the Cretaceous Kuji Group along the arc‐side basin margin. 相似文献
107.
杭州湾南岸互花米草生物海岸表层沉积物粒度分析 总被引:2,自引:0,他引:2
互花米草盐沼可显著改变潮滩的水动力条件、沉积特征和地貌演化过程。分析杭州湾南岸互花米草滩内外表层沉积物的粒度特征,互花米草生物海岸沉积物包括粘土质粉砂、粉砂、粉砂质砂和砂质粉砂4类,由东向西各断面草滩内、外沉积物中值粒径逐渐变粗,分选性变好;从低潮滩向高潮滩沉积物的中值粒径Φ值增大,分选性变差。互花米草滩外边界处形成沉积物中值粒径及分选系数的突变点。杭州湾南岸生物海岸表层沉积物以跃移质为主,悬移质次之,推移质最少;由海向岸悬移质、跃移质和推移质均有变细趋势。 相似文献
108.
109.
J. Boeyinga D.W. Dusseljee A.D. Pool P. Schoutens F. Verduin B.N.M. van Zwicht A.H.F. Klein 《Coastal Engineering》2010
This paper presents a case study on the modelling of a headland bay beach influenced by sediment input from migrating coastal dunes. The study area is the region around the town of Ingleses on Santa Catarina Island, Santa Catarina state, South-Eastern Brazil. Ingleses has been threatened by nature at two different fronts. At the north-eastern side of the town lies Ingleses Beach, a headland bay beach which seems to be subject to persistent erosion in recent years. On the south-western side the town is threatened by a migrating dunefield, which is encroaching onto houses and infrastructure, but which has not reached the beach in the past 70 years. A second dunefield in the area does not pose a direct threat to the town, but passes it on the eastern side and forms an important influence on the development of the beach. The sediment influx rate from this dunefield to the beach is 10,000 m3/year. To investigate the effect of the dunefields on the morphodynamic system, a numerical model has been created using the software packages SWAN and UNIBEST and the static equilibrium bay shape was determined by the software package MEPBAY. The result of the long-term scenario as predicted by UNIBEST agrees rather well with the static equilibrium bay shape found with MEPBAY. This provides sounds basis for the credibility of both models. Consequently, the predicted evolutional trend of the shoreline seems plausible. 相似文献
110.
古新世以来郯庐断裂的位移量及其对莱州湾凹陷的控制 总被引:4,自引:2,他引:2
高分辨三维地震可视化及方差切片分析显示,郯庐断裂渤海海域莱州湾段北北东向断裂系发育。断层在水平方差切片上的拖拽现象、断裂带内部断层的组合关系以及凹陷沉积中心的迁移等,表明古新世以来该区存在右旋走滑运动。假设在东、西两支断层的走滑拉分作用下,根据可容纳空间不变原理,设计了三角形模型、长方形模型、半地堑型模型以及地堑型模型共四种模型,计算莱州湾凹陷南北长度和凹陷深度的关系,其中半地堑模型计算得到的郯庐断裂的水平位移为7km。结合断层的平面分布和断层的切割关系,表明古新世以来郯庐断裂的走滑拉分作用难以控制莱州湾凹陷的形成,走滑拉分作用只是在走滑断裂带内部形成了局部小型洼地,其规模很小,影响非常有限。 相似文献