排序方式： 共有10条查询结果，搜索用时 93 毫秒
1
1.
2.
采用植硅体分析方法,对湖北荆门屈家岭遗址南部2015~2017年度主发掘区TN14W35探方内油子岭至石家河文化时期(5800~4200 a B.P.)的地层土样进行了系统取样分析,并重点对水稻扇型植硅体形态特征进行了研究.结果显示,遗址各文化时期土样中均含有丰富的水稻(Oryza sativa)特征型植硅体,表明稻作农业在屈家岭遗址各阶段先民植物资源的开发利用中始终占据着主导地位.同时,实验还在油子岭和屈家岭文化地层发现粟(Setaria italica)、黍(Panicum miliaceum)植硅体,但从发现数量看,粟类作物在屈家岭遗址先民农作物利用结构中只占据极小的比重.论文通过对水稻扇型植硅体形态参数测量和鱼鳞状纹饰统计发现,屈家岭遗址的水稻遗存主要属于粳稻类型,且驯化程度在油子岭文化早期时期就已经达到现代栽培稻水平.本文研究揭示了屈家岭遗址先民的农业结构、水稻类型及驯化水平,为了解江汉平原汉水东部地区新石器时代晚期人类生业形式与水稻驯化水平等提供了重要科学依据. 相似文献
3.
A recent publication on the phytolith assemblage at Fahien rockshelter, Sri Lanka (Premathilake and Hunt) is argued to represent: the exploitation of wild Musa acuminata and M. balbisiana during the Late Pleistocene; the introduction of edible diploid cultivars from the Southeast Asia–New Guinea region during the early to mid‐Holocene; the generation and cultivation of triploid banana hybrids on Sri Lanka before 6194–5994 cal bp ; and the subsequent spread of derived triploid cultivars to mainland India and westward to Africa. A careful review of the archaeobotanical research presented by Premathilake and Hunt, in the context of broader multidisciplinary evidence (agronomy, archaeobotany, genetics and linguistics) for the domestication and spread of banana cultivars, indicates that three main aspects of their argument are problematic: the lack of clarity in the characterization of banana domestication in the past; the methods used to discriminate phytoliths into banana taxa; and the promotion of Sri Lanka as a source region rather than a recipient of banana cultivars. Following reconsideration, the Fahien evidence is consistent with previous interpretations for the origins of diploid and significant triploid cultivars outside of Sri Lanka and dispersal to that island. © 2019 John Wiley & Sons, Ltd. 相似文献
4.
Felipe García-Rodríguez Laura Del Puerto Carola Castieira Hugo Inda Roberto Bracco Peter Spechmann Burkhard Wilhelm Scharf 《Limnologica》2001,31(3)
Physical, chemical and biological data from a sedimentary profile of Rocha lagoon (Uruguay) are presented. Analyses of silica remains showed that opal phytoliths, diatoms, sponge spicules and chrysophyte cysts were the most important contributors to biogenic silica. Organic matter, total nitrogen and total phosphorus were used to infer past trophic development. Physical analysis of sediments allowed us to identify five lithological units related to sea level variation and climatic events. 相似文献
5.
S.А.Аnisimova N.K.Gelety A.Y.Anisimov Т.А.Dol’nik Thomas de Boisgrollier 《世界地质(英文版)》2012,(3):191-203
The Baikal Group is one of the most important stratigraphic units in the geology of East Siberia (Upper Riphean). This paper focuses on litological-facies features based on the analysis of organic remains (stromatolites, microphitolites and microfossils), in order to better precise the age and environmental deposit conditions of the Baikal Group. The results are used to draw a correlation between all the Precambrian of deposits of the South of East Siberia. The stratigraphy of the Baikal Group is then compared to the geodynamic evolution of this region, characterized by the break-up of the supercontinent Rodinia and subsequent opening of the Paleo-Asian Ocean. Stratigraphic analogs to the Baikal Group display in most areas deposits of various minerals (complex ores, phosphoresces, bauxites etc. have been dated of the same age), so the present study would also provides an economic interest. 相似文献
6.
The diatom record of V95-2P, a 7.6 m long sediment core collected from 67 m depth, is the first from the east central portion of Lake Victoria. A soil horizon developed at the coring site shortly before 12,400 14C yr BP due to a lakewide desiccation event. The radiocarbon chronology of the older half of this core is problematic, but if our estimated chronology is correct, then aridity and evaporative concentration of the lake are indicated by the presence of Thalassiosira rudolfi from > 12,400 BP to about 10,000 BP. Abundant Aulacoseira and generally rising biogenic silica concentrations may reflect enhanced water column mixing and rising precipitation:evaporation ratios ca. 10,000-8400 BP. A lakewide reorganization of diatom assemblages occurred around 7200 BP, when Aulacoseira nyassensis largely replaced A. granulata and after which rainfall and wind-driven mixing became more seasonally restricted. Pronounced reductions in offshore diatom deposition, from about 8300-5800 BP and after 3500 BP, may have been related to declines in the duration and/or intensity of wind-driven mixing. Increased aridity, and possibly deforestation in the lake basin, is indicated after 1400 BP. 相似文献
7.
基于在长江口开展的三个综合航次对河口生物硅组成、行为和收支进行了研究。结果表明，长江口生物硅主要是由植硅体、硅藻和海绵骨针三部分组成，其中植硅体有16种形态，在高混浊区对生物硅的贡献量为23%-83%。收支计算显示，长江输送的生物硅是河口区获取外部生物硅的主要途径，占河口生物硅总输入量的95%；维持河口生物硅水平的主要过程是初级生产（55 Gmol a-1）和沉积过程（46 Gmol a-1）；初级生产所贡献的生物硅分别是长江生物硅输送量的2.3倍和河口区向外输送生物硅的63%。从河口区向东海和黄海输送的生物硅是26 Gmol a-1，与长江的生物硅输送量相当；河口区沉积的生物硅是向外输送量的1.7倍，在其中植硅体贡献了53%至88%的生物硅，表明河口是陆源生物硅汇的作用；反风化作用也是河口活性硅去除的一个重要途径。本研究显示植硅体是河口生物硅的重要组成部分，长江口在生物硅收支与循环中表现出汇的作用。 相似文献
8.
植硅体分析在古环境、古生态、环境考古、植物分类等众多领域研究中逐渐显示出其重要的作用,其应用潜力依赖于现代植硅体形态基础研究工作的深入。文章主要针对我国热带、亚热带地区常见的棕榈科15个属20个种植物进行了植硅体形态鉴定和多项形态参数(大小、突起等)的测量分析,同时对旅人蕉科的白花扇芭蕉、蝎尾蕉科的黄芭蝎尾蕉、苏木科的无忧树进行了对比研究。结合聚类分析方法把植硅体形态分为5个大的类型,棕榈科植硅体主要包括刺球形、水母形和草帽形3种形态。白花扇芭蕉植硅体呈褶球形,黄芭蝎尾蕉植硅体呈飞梭形,无忧树不含有植硅体。同时,给出了不同类型形态参数的大小和范围,为利用棕榈科植硅体等进行古环境研究提供了基础。 相似文献
9.
Lisa‐Marie Shillito 《第四纪科学杂志》2011,26(6):576-588
Simultaneous thin section and phytolith observations of finely stratified anthropogenic deposits from the Neolithic settlement of Çatalhöyük, Turkey, dated between 7400 and 6000 BC provide evidence for both the depositional context and phytolith assemblage of these deposits. Although extracted phytoliths provide a general picture of vegetation that supports existing evidence of a local wet marshland environment, comparisons with observations of phytoliths in situ indicate a diverse range of microcontexts, as well as depositional and post‐depositional processes that influence phytolith size. This has implications for studies that use conjoined phytolith size as a proxy for water availability and early agricultural practices. Observations indicate a significant background noise of phytoliths and micro‐charcoal in the deposits, linked to the frequent use of fire, which has implications for interpreting assemblages where phytolith counts are low, such as from floors of buildings. This study confirms the usefulness of phytoliths in providing information on human plant use and environment where the taphonomy of the deposits is clear, and provides new evidence for wet farming of at least some of the wheat found at the site. It also suggests there needs to be greater consideration of phytolith taphonomy, which can be provided to an extent by combining phytolith analysis with thin section micromorphology. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
10.
H. Inda F. García-Rodríguez L. del Puerto V. Acevedo D. Metzeltin C. Castiñeira R. Bracco J. B. Adams 《Journal of Paleolimnology》2006,35(4):699-713
Paleolimnological data are presented on trophic development, climatic change and sea level variations in Rocha Lagoon, a 72 km2 coastal lagoon in southern Uruguay. Using a sediment core that extended from 7000 to about 3700 yr BP, analyses of organic
matter, carbonate, diatoms and chrysophyte cysts were used to track the early Holocene paleolimnological conditions of Rocha
Lagoon. Opal phytoliths were also counted and identified, both temperature and humidity indices were calculated, and Opal
Phytolith Association Zones (OPAZ) were identified by performing Principal Coordinates Analysis (PCO). Diatom Association
Zones (DAZ) corresponding to marine/brackish and brackish/freshwater episodes were closely related to changes in trophic state.
Those DAZ representing marine/brackish stages exhibited a lower trophic state than those DAZ dominated by brackish and freshwater
diatoms. This highlights that during the first Holocene marine transgression, Rocha Lagoon did not continuously exhibit marine/brackish
conditions as reported in previous papers. Instead, three brackish/freshwater episodes related to sea level variation and
changes in humidity were identified. The first episode, by ~6000 yr BP, was related to sea level change as no significant
changes in either temperature or humidity indices were observed. The second episode, between 5000 and 4400 yr BP, was related
to both a sea level decrease and an increase in humidity, as a transition from humid to very humid climate was inferred. Concomitant
decreases in salinity and increases in trophic state were also observed. The third episode, after ~4000 yr BP, was related
to the end of the first Holocene regressive phase when sea level was slightly below present levels. Further decreases in salinity
and increases in trophic state were detected. The paleoclimatic trends inferred in this study were in close agreement with
other regional studies on climatic change, as cool temperatures were inferred. However, major changes in humidity were also
detected. A humid to very humid climate was inferred for ~7000–4500 yr BP, but the occurrence of a semiarid/arid climate was
inferred for ~4500–3700 yr BP. Our data suggest that during transgressive and regressive events there might be higher frequency
and lower amplitude sea level oscillations that might lead to changes in salinity and trophic state of coastal aquatic systems.
Such oscillations could only be tracked by high resolution analyses of sedimentary records and could be best interpreted with
complementary data on paleoclimate. In addition, microfossils such as diatoms and opal phytoliths were shown to be very sensitive
to such paleoenvironmental changes. 相似文献
1