共查询到20条相似文献,搜索用时 15 毫秒
3.
分类号:P512.2 文献标识码:A 总被引:1,自引:1,他引:0
ZHONG Jian-hua ZHONG Jian-hua WU Kong-you NI Jin-ren 《沉积学报》2000,18(4):527-533
In recent years, the flow of the Yellow River has often beeninterrupted, which has resulted in exposure of channel bars and point bars, and even extensive exposure of the riverbed. Consequently, a large number of rill marks have developed. They are diverse in morphology. According to the hydrodynamic types of their formation, they can be grouped into 6 categories, i. e. the wave-eroded, backwash, seepage, rain-eroded, water-drainage and runoff rill marks. Morphologically, they can be divided into more than ten types: the linear, tooth-shaped, comb-shaped, fence-like, ear-like, braided, branched, leaf-like, flower-like, root-like, dendritic, net-like, radial etc. Their cross sections include the broad-u type (the width/depth ratio is over 2, and may reach 10-20), U-type (width/depth ratio from 1 to 2), V-type, Ω-type and (-type. Their occurrences may be attributed to the variations in composition, grain-size, color, fabric and morphology. They have 5 scales: the micro-scale (length and width within 1 cm), small-scale (length and width within 10 cm), medium-scale (length and width ranging from 10-100cm), large-scale (length and width 1-5 m) and giant- scale (length or width over 5 m). 相似文献
4.
5.
6.
7.
8.
浙江象山“石浦灰岩”一直是地质界长期争论的问题。本文根据古生物化石、地层、岩性对比及地层层理构造、侵入体的同位素绝对年龄、微量元素、沉积磷酸盐法、岩石组构、硅质岩的成因、及火山碎屑岩中Na_2O,K_2O,FeO,Fe_20_3,MgO与陆相火山岩的差别,提出其时代应属于晚侏罗—早白垩世,偏向早白垩世,其11—39层地层为海陆过渡相沉积。并推测东海海域可能存在一个海相或过渡相的早白垩世地层。 相似文献
10.
11.
吴玮江 《中国地质灾害与防治学报》2005,16(3):103-103
地处西北黄土高原的甘肃省会宁地区出露地层为第四系马兰黄土,其垂直节理发育。在陡立的黄土边坡部位由于卸荷作用,垂直节理多张开。在重力作用下,土体沿此结构面逐步崩塌,残留部分常形成高耸独立的方形黄土柱,高约8m。这类土柱在干旱气候条件下可保留很长时间。封面照片说明$甘肃省科学院地质自然灾害防治研究所@吴玮江 相似文献
12.
13.
14.
16.
18.
一路上,是一座座突兀而起的山峰。
张家界的山是世界上罕见的石英砂岩峰林,它不似黄山庐山的峰林那样俊朗恢宏,边绵不绝,却如同一个性格怪张的画师,想到哪便行至哪,或是大笔一挥或是微微小拂,那山便没有规则的随意耸出,它们一律清瘦孤立,似乎没有根地平地而空,直冲云霄,又似杂技大师的叠罗汉层层叠叠,半悬半靠,待你为它的孤绝悬心之时,却突然现出那样两至三座山峰安然相望,相依非靠。 相似文献
19.
陈宏德 《地壳构造与地壳应力》1992,(2):61-63
日本有名的地壳物理学.地震学和测地学专家田中丰生于1930年4月20日,京都大学理学博士.现任京都大学理学部讲师.田中丰积极参与各种学术活动。是日本测地学会、地震学会、日本火山学会、日本第四纪学会.材料学会会员.还是上述5个学会的专业委员会的委员.他长期活跃在第一线。有丰富的实践经验. 相似文献
20.