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Study on Sedimentary Diatoms of Late Holocene from Middle Offshore Sea Area of Fujian Province

Author: ZhangJinPeng
Tutor: LiChao
School: Xiamen University
Course: Marine Geology
Keywords: Sedimentary diatom Late Holocene Fujian Province
CLC: Q914
Type: Master's thesis
Year: 2009
Downloads: 160
Quote: 1
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Abstract

Micropaleontology - diatoms is an important symbol of biological retroactive change of geological environment, is widely used in the the Cenozoic sedimentary layer, in order to distinguish the environmental evolution. Fujian and central coastal waters of the shallow water of the west side of the Taiwan Strait by sea distribution, topography, climate, tectonic movement, both terrestrial and marine hydrological multiple elements and control of human activities is more obvious in the area. Through the identification and analysis of diatoms in marine sediments of diatom species composition, distribution characteristics and environmental factors correlated to explore the of diatoms distribution of response and late Holocene in this area of ??the marine environment of the marine environment changes, and deepened understanding of the evolution of the history of the study of sea area. The main conclusions of this study and understanding as follows: (1) through the surface sediment diatoms on the of Minzhong inshore waters (Haitan Island - chongwu Peninsula) analysis, 45 were identified diatoms 59 genera and 246 species (including variants and variants). Sedimentary the rich diatom species diversity. Including both freshwater species and coastal species, but also the emergence of oceanic species, seawater species and brackish species the largest number; both cold-water species and the emergence of the northern temperate species also have a considerable number of warm-water species, the number of species of wide temperature the most. (2) analysis of the characteristics of surface sediment diatoms abundance, diatom distribution differences. Clay, silt and fine component in the overall sediment the rich diatom shell, from the the mainland near diatoms shell is relatively rich. Gulf abundance value, a significant effect on the landing source input of nutrients and human activities. The low value area in the eastern part of Haitan Island show that the role of the upwelling diatom shell bury constraints. (3) combined percentage of genera and species of principal component analysis and correspondence analysis method of quantitative ecology, surface sediment diatoms of the study area is divided into four types and several sub-classes: the first class of the main features is with slot straight chain algae (Melosira sulcata (Ehr.) Kutzing), Pham Thi the round box the algae (Pyxidicula weyprechtiiGrunow) star handle chain algae (Podosira stelliger (Bail.) Mann) was the dominant populations; second class with slot straight Chain algae, wavy spokes tuck algae (Actinoptvchus undulatus (Bail.) Ralfs) as the main body; third category with slot Melosira centrifugation columns Thalassiosira pseudonana (Thalassiosira excentrica (Ehr.) Cleve) and (or) wavy spokes tuck Algae main populations; the fourth category overall with slot Melosira, the columnar Cyclotella (Cyclotella stylorumBrightwell) and (or) stripes Cyclotella (Cvclotella striata (Kuetz.) Grunow) as the main body. The principal factor analysis of the main factors to affect the the central Fujian coastal waters of sedimentary diatom distribution: coast of the low-temperature water and the corresponding brackish or sea water environment and biased in favor of the heated environment of the high temperature and high saline body. That this area by longshore currents and warm water is more common. The two main environmental factors covering land and sea distribution, topography, climate, hydrological conditions. (4) in the surface sediment samples identified Africa round sieve of algae (Coscinodiscus africanusJanisch), boat-shaped saddle chain algae (Campylosira cymbelliformis (A.Schmidt) Grunow) pyramid cap crown algae (Stephanopyxis turris (Grev.et Arnott offsite kinds of) Ralfs). Boat-shaped saddle chain algae (first recorded in 2004 species) in the six stations detected reflect the species may have adapted to the Fujian coastal waters of the aquatic environment, need to further their conduct detection research, proven ecological communities and whether there is a potential threat to the aquatic environment. (5) in the from ZK18 hole Core Sediments identified diatoms 40 genera and 116 species (including varieties and variations). Dominant populations: the love's convergence Cyclotella (Actinocyclus ehrenbergii Ralfs), wavy spokes tuck algae, snake round sieve mesh algae (Coscinodiscus argus Ehrenberg) the tongue shaped the circular sieve algae (Coscinodiscus blandusA.Schmidt), Rockwell the circular sieve algae (Coscinodiscus rothii (Ehr.) Grunow), radiation columns round sieve algae (Coscinodiscus radiatus Ehrenberg), columnar Cyclotella, stripes Cyclotella, with slot Melosira, star-shaped handle chain algae, Pham Thi round sieve algae, cellular triangulation algae (Triceratium favus Ehrenberg). ZK18 hole diatom abundance changes, combined with the advantage of changes in the population can be divided into four of diatoms band and several subzones. Combination of particle size analysis, reflecting the central coastal waters in Fujian in 1500 depositional environment occurred a series of changes, has experienced a series of 250 ~ 100 cm (about 600 to 1440) regression, while more than 100 cm (about 1440 to 2003 years) marine environment is similar to the modern, the reaction of the marine environment for the transition of the shallow marine environment of the coastal environment and evolution to a shallow water environment. In the sea retreat background, the sea retreat, the complex nature of sea level fluctuations. (6) combined with the historical data of earthquakes, typhoons, climate change, history books, etc., in the sedimentary features dramatic changes in the horizon, identify possible extreme geological events, weather events, explore climate fluctuations in the specific horizon biological, geological record the response, as well as sedimentary characteristics response to human activities.

Study on Sedimentary Diatoms of Late Holocene from Middle Offshore Sea Area of Fujian Province

Abstract

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