首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2篇
  免费   0篇
  国内免费   1篇
地质学   1篇
自然地理   2篇
  2003年   1篇
  2002年   1篇
  1998年   1篇
排序方式: 共有3条查询结果,搜索用时 593 毫秒
1
1.
The seed-like larval cases of hydroptilid caddis flies may be mistaken for plant remains in subfossil studies. However, being correctly identified, they may be important for the interpretation of former freshwater environments. Two such subfossil caddis fly remains from Holocene lake sediments and river deposits are described morphologically and their palaeoecological significance interpreted.  相似文献   
2.
Sediments from Tugulnuit Lake in the Okanagan Valley of British Columbia, Canada, were examined for chironomid assemblages. The chironomid stratigraphy obtained encompasses the last 4000 to 5000 years and suggests a warm and fairly stable climate typical for a temperate lake at low- to mid-elevation. This is indicated by the even distribution of warm-water taxa, such as Cladopelma, Dicrotendipes, Polypedilum, Pentaneurini, Stempellina, Stempellinella/Zavrelia and Pseudochironomus throughout the core. Very few cold-water taxa occurred in the sediments. However, stream inputs have had a major impact on Tugulnuit Lake. Sandy sediments and the appearance of Simuliidae and stream-inhabiting chironomid taxa (e.g., Brillia/Euryhapsis, Eukiefferiella/Tvetenia, Rheocricotopus) indicate that a stream intruded into the current lake's basin ca. 3800 yr Before Present (BP). Sediments deposited prior to, and after, the stream's intrusion show a distinctly different chironomid assemblage exhibiting chironomid taxa more typical for lentic habitats. This result indicates that chironomids can serve to detect past stream influences on lake environments. Thus, rheophilic chironomids preserved in lake cores provide a new alternative for reconstructing stream palaeoenvironmental records.  相似文献   
3.
古昆虫学的发展、存在问题与展望   总被引:8,自引:2,他引:8  
洪友崇 《地质通报》2003,22(2):71-86
对国际古昆虫学的发展作了回顾,大体上将其分为两个大的发展阶段;开始与积累阶段,发展和繁荣阶段。这两个阶段又可分为8个时期。在古昆虫学的发展史上曾有过3次历史性的重要总结。即Handlirsch A(1906-1908)的《Die Fossil Insketen und die Phylogenie der rezenten Formen》,Rohdemdorf b.b.et al(1962)的《Foundamentals of Paleonentomology》,Carpenter F.A(1992)的《Hexapoda》,以及各国区域性昆虫化石研究和以分类为核心的总结,等等。通过国际古昆虫工作者的共同努力。一部分类为核心的古昆虫学专著基本完成。在国际古昆虫学及中国古昆虫学研究新成就的基础上,提出了古昆虫学研究中还存在的一些问题;如加强基础研究工作,包括化石采集、分类、描述;古昆虫学研究与地质学、地质背景相结合;化石昆虫群的演化及其发展史的建立:昆虫的起源;加强国际合作与交流,崇尚科学精神,促进学科发展等。  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号