共查询到20条相似文献，搜索用时 140 毫秒
1.
我院煤田教研室黄(西辶)和,温显端,王根发等三同志,经过对滇东黔西晚二叠世含煤岩系沉积构造和我国东部海岸现代潮坪沉积构造的精心研究发现了迄今为止国内外刊物从未提到过的潮坪特有的潮汐周期层序。这种潮汐周期层序是低能潮坪上的特征,在低能潮沟中保存最好。他们区分出两种类型层序: 相似文献
2.
3.
4.
吉林南部老岭群原岩恢复和古沉积环境 总被引：2，自引：0，他引：2
吉林南部地区老岭群划分为下亚群大东岔组、临江组和大栗子组,上亚群石青沟组和珍珠门组.老岭群原岩主要类型为泥岩、砂岩、粉砂岩、粉砂质黏土岩、泥砂质岩、石英砂岩、白云质黏土岩及杂砂岩等,均具有明显的沉积特征.分析显示吉南地区的古沉积环境变迁与海平面的升降旋回对应,分别经历了下亚群临江期高能滨海相,大栗子组低能浅海相、浅海陆棚相、半封闭湖相到高能的潮坪环境沙坪相过渡,以及上亚群石青沟组高能滨海相到低能半闭塞台地相的过渡,珍珠门组经历了由低能半闭塞台地相、开阔台地相到高能台地边缘相,再到低能浅海陆棚相的过渡. 相似文献
5.
根据我国东部海岸现代潮坪沉积物和古代潮汐沉积物的研究,新发现一种潮汐沉积物所具有的特殊沉积构造,这种沉积构造可区分出三种类型,特征明显,易于鉴定,反映潮汐运动规律,命名为“潮汐周期层序”。用这种沉积构造作为古代潮汐沉积物的鉴定标志,将大大提高鉴定的可靠性。 相似文献
6.
海南高隆湾海滩生物碎屑分布及其对沉积物粒度特征的影响 总被引：2，自引：0，他引：2
在热带砂质海岸,生物碎屑是海滩沉积物的重要组成部分,其分布和变化影响海滩沉积物的粒度特征。采用添加过量盐酸和双氧水的方法对海南高隆湾海滩表层沉积物进行了去生物碎屑前后粒径分布的对比,并结合海滩高程测量分析,结果表明:（1）海滩剖面上沉积物中生物碎屑的含量主要受到海水动力的影响,且生物碎屑颗粒较粗、重量较大,在高潮时由波浪流推上海滩并滞留。（2）海滩沉积物中生物碎屑的分布主要受三方面影响:一是地形及常涌浪向;二是区域中养殖业产生的生物碎屑;三是岸外发育的珊瑚礁坪。（3）海滩沉积物中生物碎屑的含量随季节变化,冬季至春季由海水供给的生物碎屑减少、进一步分解,使得北部海滩生物碎屑含量减少;而珊瑚碎屑的稳定供给和春季较强的波浪动力条件又使研究区南部断面的生物碎屑含量增加。（4）海滩沉积物中粗颗粒所含生物碎屑多于细颗粒中的生物碎屑,生物碎屑粒径主要为-1~2,即粗砂至细砾。沉积物中生物碎屑含量愈大,对粒径参数的影响也愈大。 相似文献
7.
海岸沙丘对风暴响应研究进展 总被引：3，自引：0，他引：3
《地球科学进展》2017,(7)
全球海岸沙丘主要分布地区频繁遭受风暴袭击,风暴成为海岸沙丘形成演变的一个高能影响因子,也是研究波浪—海滩—沙丘相互作用的重要内容之一。从海岸沙丘形态对风暴响应、海岸沙丘沉积物对风暴的响应、海岸沙丘对风暴响应机理及其研究方法与技术等方面综合评述了国内外海岸沙丘对风暴响应的研究进展,并针对目前研究中存在的问题提出了今后发展的主要研究方向。 相似文献
8.
利用对深圳西冲湾两个岬角之间的海蚀地貌及其海滩沉积物的野外调查资料,鉴定出三级海蚀平台,对其分别进行了高程换算,并借助于海蚀拱门和海蚀刻槽的测定,以及对典型沙层沉积剖面序列的分析和14C测年,认为：虽然西冲湾海蚀平台的岩石类型是不易被侵蚀的花岗岩,但是此处的海蚀地貌（主要是海蚀平台）以及海滩沉积物（主要是海滩岩）可以作为全新世存在高海平面的证据。此外,针对我国海岸带人口密度大,人类活动对海岸影响程度大的现况,提出了未来研究南海北部海岸新构造运动存在的问题以及其解决方案。研究成果对于认识南海北部海岸全新世的构造运动、海平面变化以及与其他地区新构造运动的对比研究都具有重要的意义。 相似文献
9.
陆相碳酸钙沉积特征及水能量分类 总被引：1，自引：1，他引：0
以野外观察及室内试验分析为基础,讨论了陆相碳酸钙沉积类型与水能量条件的相关关系,并定量和定性地讨论了各类型之间的水能量界线;指出陆相碳酸钙沉积包括超高能、高能、低能及超低能四种沉积类型;根据其位置它们又可划分为地表和地下两种类型。这些陆相碳酸钙的相应的沉积水能量条件分别为超高能水、高能水、低能水及超低能水。此外,还描述了各类陆相碳酸钙的各自的发育特征。 相似文献
10.
罗平生物群是继二叠纪末全球生物大灭绝后海洋生态系统全面复苏的典型代表.为了更全面地认识罗平生物群产出的沉积环境,通过露头观察、微相分析等方法对云南省罗平县宜石打剖面中三叠统关岭组二段进行了研究,共识别出开阔台地、局限台地（泻湖）、潮坪、台盆、台内滩5种沉积相类型.台内滩的颗粒类型以似球粒、包粒为主,其次为少量鲕粒、生物碎屑,颗粒之间主要为亮晶胶结,局部含少量灰泥,滩体规模较小,指示中等水能量环境,且由下向上具多期发育特征.综合研究表明,中三叠世安尼期Pelsonian亚期早期发生了全球性的海平面上升,导致沉积环境水深迅速增加.研究区沉积相从潮坪相迅速转变为台内盆地相,其相对低能缺氧的环境有利于罗平生物群化石的保存. 相似文献
11.
小洋岛现代海岸类型及其特征 总被引：1，自引：0，他引：1
小洋岛上岩岸、沙滩、泥滩的分布很有规律，这是地壳运动、海蚀风化和波、潮、流共同作用的结果。它不仅是传播地学知识的天然课堂，而且可为洋山深山深水港的建设提供启示。岛上不但有众多奇峰异石与金黄色沙滩组成的美丽自然风光。还有古代摩崖石刻、题记及即将建设的现代化深水港构成的人文景观，在洋山港建设的同时，应该充分重视小洋岛旅游资源的保护和开发。 相似文献
12.
Erich R. Gundlach Christopher H. Ruby Miles O. Hayes Anne E. Blount 《Environmental Geology》1978,2(3):131-143
The supertankerUrquiola grounded, exploded, and burned at the entrance to La Coruña harbor (Spain) on May 12, 1976. A total of 100,000 tons of Persian Gulf crude oil was lost, of which about 30,000 tons washed onto shoreline environments. From May 17 to June 10, 1976, the impact and interaction of oil on fine-sand, coarse-sand, and gravel beaches and on sheltered and exposed rocky coasts was monitored in detail. At 32 localities, the beach was profiled, trenched, extensively sampled, and photographed. Another 67 stations were examined for surficial oil coverage and distribution. The surficial distribution of oil on the beaches was influenced primarily by wave activity, tidal stage, and oil quantity. Heaviest accumulations formed along the high-tide swash line. Within beach sediments, oil was present at distinct oiled sediment layers, which were often deeply buried. The depth of burial was related to wave energy and sediment type. Deepest burial (1 m) was on a high-energy, coarse-sand beach (Mz=0.82φ). Burial on fine-sand beaches was less than 30 cm. The thickness of oiled sediment depended on sedimentary characteristics, the quantity of oil present, wave action, and capillary forces. Oil-soaked sediment, as much as 65-cm thick, occurred on coarse-grained beaches. On fine-sand beaches, oiled sediment was limited to thicknesses of 10 cm or less. On rocky shores, oil distribution was determined primarily by wave energy. Along high-energy, cliffed, or steeply dipping rocky areas, wave reflection kept the oil approximately 5 m offshore and contamination was minimal. In low-energy, sheltered areas, oil readily accumulated, causing apparent environmental damage. 相似文献
13.
Analysis of 75 vibracores from the backbarrier region of Kiawah Island, South Carolina reveals a complex association of three distinct stratigraphic sequences. Beach ridge progradation and orientation-controlled backbarrier development during the evolution of Kiawah Island, and resulted in deposition of: (1) a mud-rich central backbarrier sequence consisting of low marsh overlying fine-grained, tidal flat/lagoonal mud; (2) a sandy beach-ridge swale sequence consisting of high and low marsh overlying tidal creek channel and point bar sand, and foreshore/shoreface; and (3) a regressive sequence of sandy, mixed, and muddy tidal flats capped by salt marsh that occurs on the updrift end of the island. Central backbarrier deposits formed as a result of the development of the initial beach ridge on Kiawah Island. Formation of this beach ridge created a backbarrier lagoon in which fine-grained estuarine and tidal flat mud accumulated. Washovers, oyster mounds, and tidal creek deposits form isolated sand and/or shell-rich lenses in the lagoon. Spartina alterniflora low marsh prograded into the lagoon as the tidal flats aggraded. Barrier progradation and sediment bar-bypassing at Stono Inlet created digitate beach ridges on the northeast end of Kiawah Island. Within the beach-ridge swales, tidal flats were disconformably deposited on shoreface and foreshore sand of the older beach ridges. Tidal creek drainage systems evolved to drain the swales. These rapidly migrating creeks reworked the tidal flat, foreshore, and shoreface sediments while redepositing a fining-upward sequence of channel lag and point bar deposits, which served as a substrate for salt marsh colonization. This resultant regressive sedimentary package marks the culmination of barrier island development and estuary infilling. Given enough time and sedimentation, the backbarrier sequence will ultimately prograde over the barrier island, reworking dune, beach, and foreshore sediments to form the upper sand-rich bounding surface of the barrier lithosome. Preservation of the regressive sequence is dependent upon sediment supply and the relative rate of sea-level rise, but the reworking of barrier islands by tidal inlets and migrating tidal creeks greatly alter and complicate the stratigraphic sequence. 相似文献
14.
On the south‐west coast of Vancouver Island, Canada, sedimentological and ichnological analysis of three beach–shoreface complexes developed along a strait margin was undertaken to quantify process–response relations in straits and to develop a model for strait‐margin beaches. For all three beaches, evidence of tidal processes are expressed best in the lower shoreface and offshore and, to a lesser extent, in the middle shoreface. Tidal currents are dominant offshore, below 18 m water depth (relative to the mean spring high tide), whereas wave processes dominate sediment deposition in the nearshore (intertidal zone to 5 m water depth). From 18 to 5 m water depth, tidal processes decrease in importance relative to wave processes. The relatively high tidal energy in the offshore and lower shoreface is manifest sedimentologically by the dominance of sand, of a similar grain size to the upper shoreface/intertidal zone and, by the prevalence of current‐generated structures (current ripples) oriented parallel to the shoreline. In addition, the offshore and lower shoreface of strait‐bound beach–shoreface complexes are recognized ichnologically by traces typical of the Skolithos Ichnofacies. This situation contrasts to the dominantly horizontal feeding traces characteristic of the Cruziana Ichnofacies that are prevalent in the lower shoreface and offshore of open‐coast (wave‐dominated) beach–shorefaces. These sedimentological and ichnological characteristics reflect tidal influence on sediment deposition; consequently, the term ‘tide‐influenced shoreface’ most accurately describes these depositional environments. 相似文献
15.
16.
Grain size analysis and characterization of sedimentary environment along Thiruchendur coast, Tamilnadu, India 总被引：1，自引：0，他引：1
V. C. Rajganapathi N. Jitheshkumar M. Sundararajan K. H. Bhat S. Velusamy 《Arabian Journal of Geosciences》2013,6(12):4717-4728
Thiruchendur coast of southern Tamilnadu, India has been studied for grain-size spectrum and textural parameters namely mean, sorting, skewness and kurtosis. The grain-size spectrum shows a marked variation in the berm, high tide line (HTL) and low tide line (LTL) stretches. Variation in energy condition is controlled by geomorphology of the sedimentary beach. Textural pattern shows complicated profile as a result of the fluctuation in the physicochemical conditions due to the sediments and the marine interactions. Abundance of the medium sand to fine sand shows the prevalence of comparatively moderate- to low-energy condition in the Thiruchendur area. Linear discriminate function of the samples indicates an aeolian, shallow marine deposition environment and less influence of fluvial (7 %) process. CM diagram (C = one percentile in microns M = medium in microns) of Thiruchendur coast sediments suggests that deposition takes place by (1) rolling, (2) bottom suspension, (3) graded suspension. This is also supported by the wave energy in different stretches in beach line and also tractive current figure implies the sediments disturbed by the tractive and turbidity currents. The heavy minerals are concentrated in the berm (average, 11.8 %) and high tide line (average, 11.2 %) because of high-energy condition and aeolian action. Quartz microtextures show the mechanical action due to high-energy condition in Manapad and Kuduthalai areas, the chemical action because of to low-energy condition along the Thiruchendur, Kallamozhi areas. 相似文献
17.
Sourav Saha Anupam Ghosh Santanu Banerjee Pratul K. Saraswati Stuart D. Burley 《Journal of the Geological Society of India》2011,77(5):409-418
This study highlights lithofacies and biofacies characteristics of the open coast tidal flat near Daman on the eastern flank
of Gulf of Khambhat. Sedimentological and biological observation record six facies within the tidal flat area including older
beach, beach face, sand flat, mud flat/mixed flat, sand bar and beach rock. Distinct sedimentary structures, foraminiferal
assemblage and bioturbation intensity characterize each facies. A wide variety of wave and current generated sedimentary features
characterize the sand flat facies. Semiconsolidated sands of older beach running parallel the coastline at a level higher
than the present beach face possibly records the latest sea level highstand. The beach rock reflects early cementation of
sands in tropical environments. Foraminifera are widely distributed in sand flats, mixed flats and mud flats and grouped into
two biofacies — Ammonia-Elphidium-Quinqueloculina biofacies (sand flat and mixed flat) and Trochammina-Miliammina biofacies (mud flats). The beach face and sand bar facies contain forminifera reworked from sand flat and mud/mixed flat.
Seasonal variation in depositional style is marked by deposition of fresh mud deposited over large areas of the intertidal
flat during monsoon time, most of which is washed away by waves and current actions well before the onset of the next monsoon. 相似文献
18.
低能海岸的垂直层序和风暴沉积 总被引：5，自引：0，他引：5
我国淤泥质海岸由微型和小型层序构成。微型层序主要是潮汐作用形成的,小型层序由粗、细粒单层构成,其中粗粒单层形成于风暴时期,细粒单层形成于平静天气。小型层序系完整的风暴层序。在游泥质海岸层序中风暴沉积的厚度超过非风暴沉积,且排列有序。低潮坪沉积物粗,向陆向海变细,从而构成中间粗、两端细的淤泥质海岸典型垂直层序。随着条件和因素的变化,典型垂直层序可以产生若干变异,识别出三种变异层序。 相似文献
19.
鲕粒,豆粒磷块岩的显微结构和生成特点 总被引：4，自引：0，他引：4
晚震旦世陡山沱组和早寒武世渔户村组、辛集组磷矿中有各种鮞粒、豆粒磷块岩。豆粒、鮞粒内核的成分和结构复杂,有来自陆地的各种岩石砂屑、细砾,也有盆内沉积物破碎成的各种内碎屑。鮞粒、豆粒的壳层是同心纹层状磷灰石,它是内核在富磷海水扰动中逐层淀积而成。大部分豆粒、鮞粒在滨海高能浅水中与陆源砂、砾和岔内碎屑沉积在一起,少量鮞粒则沉积在滨外深水低能环境巾。豆粒、鮞粒和碎屑等沉积后又被不同物质胶结。 相似文献
20.
三亚海岸演变与人工海滩设计研究* 总被引：12，自引：0，他引：12
三亚海岸位于海南岛南部,属弱潮海区,以来自开阔外海的偏南向风浪为海岸优势动力。三亚海岸经历了从基岩港湾海岸到岬角与港湾相间的海蚀-海积海岸的发育演化过程,沙坝(沙咀)发育始于中更新世初期,珊瑚礁发育始于8kaB.P. ,目前海岸总体处于相对平衡发展阶段。对三亚地区海岸地貌、动力及泥沙运动的调查研究,总结三亚湾及其周边不同类型海滩的特点,提取其海滩参数。依据处于不同发展时期的自然海滩形成演变的条件和规律,设计建构三亚白排人工海滩的关键参数。设计海滩总长度约400m,宽度\{40~\}50m,坡度4.5°~5.0°,相对高度约2m,填砂M为0.5,以粒径1.0~\}0.5mm的粗砂为主,总填砂量48000m3。从滩面物质和滩面坡度两个关键方面,利用代表性的数学模型,检验了设计海滩的稳定性。本项研究旨在服务白排人工海滩建设,研究方法对海滩侵蚀防护与同类海岸工程建设等具有参考价值。 相似文献