Radiocarbon dating and archeology in North America

The history of the development of a radiocarbon chronology shows how the establishment of the times of events and the order of them has greatly improved the understanding of prehistory in North America. This is true also of other parts of the world. Too little has been said of existing discordance between archeologically determined sequences, and interregional associations, and the radiocarbon chronology. It does appear that these will be resolved as additional dates are added and as the results become more finely calibrated so that secular variations may be accounted for. The collaborative aspect of the venture was apparent at the outset. Nevertheless no one expects an archeologist to delve into nuclear physics and geochemistry, and vice versa. There is great need, nevertheless, for the man in the laboratory to comprehend the difficulties of sample collecting and of judgement of the significance of the source of organic matter to be dated. At the same time, the archeologist must become more familiar with the importance of the various steps in the processing of the sample and with, what is most vital, interpretation of the significance of the numbers that appear on the counters.     

Status of the Pleistocene Wisconsin Stage in Central North America

A brief review of the history of the Wisconsin Stage in Pleistocene stratigraphy and of research since 1950 shows that post-Sangoman glacial drift older than the Wisconsin drift reported in the older literature is present in central North America. Known and possible stratigraphic positions of the relevant units are shown.     

Finite Radiocarbon Dates of the Port Talbot Interstadial Deposits in Southern Ontario

Three new finite radiocarbon dates Suggest that (i) the thermnal maximum of the Port Talbot interstadial ocurred prior to 47,000 years before the present and (ii) the interstadial deposits were overridden by a glacial advance approximatels 44,000 years before the present. To facilitate correlaltions with other areas, new rock-stratigraphic names are proposed for the Port Talbot type section.     

Radiocarbon variability in the western North Atlantic during the last deglaciation

We present a detailed history of glacial to Holocene radiocarbon in the deep western North Atlantic from deep-sea corals and paired benthic-planktonic foraminifera. The deglaciation is marked by switches between radiocarbon-enriched and -depleted waters, leading to large radiocarbon gradients in the water column. These changes played an important role in modulating atmospheric radiocarbon. The deep-ocean record supports the notion of a bipolar seesaw with increased Northern-source deep-water formation linked to Northern Hemisphere warming and the reverse. In contrast, the more frequent radiocarbon variations in the intermediate/deep ocean are associated with roughly synchronous changes at the poles.     

不同播期对豫东地区小麦产量性状的影响

为进一步明确小麦产量及其相关性状与播期的关系,选育适播期广的小麦新品种,为豫东地区小麦生产提供保障。研究选择了6个小麦品种,分别在2020~2021年和2021~2022年在商丘市农林科学院双八基地进行了为期两年的播期对小麦产量及其产量性状影响的试验。研究发现播期和品种对小麦产量具有显著影响。播期对株高、最高群体、667 m²穗数、成穗率和千粒重也有显著影响;千粒重和产量均在T2播期（10月15日）达到最高,且显著高于其它播期。6个参试品种中,尚农6在不同播期下其株高、667 m²穗数、千粒重成穗率和产量均表现最好。     

胶东玉米品种的筛选与播期研究

在大田条件下,采用裂区设计研究了播期对不同玉米品种生育期、抗逆性及产量的影响。结果表明,播种越晚,生育期越短,产量也越低。6月1日、6月10日播种的玉米粗缩病最重。本试验条件下,从播期和品种本身特性等多方面比较,春播以5月1日至6月1日播种为宜,产量较高,选用品种为登海3622、先玉335;套种玉米选用登海3622、先玉335、金海5号;夏直播玉米以选用先玉335、郑单958为宜。