C_5－C_（15） hydrocarbons in surface sediments from the Bransfield Strait， Antarctica

（唐运千）（蒋家桢）（卢冰）（眭良仁）Ｃ_５－Ｃ_（１５）ｈｙｄｒｏｃａｒｂｏｎｓｉｎｓｕｒｆａｃｅｓｅｄｉｍｅｎｔｓｆｒｏｍｔｈｅＢｒａｎｓｆｉｅｌｄＳｔｒａｉｔ，Ａｎｔａｒｃｔｉｃａ￥ＴａｎｇＹｕｎｑｉａｎ；ＪｉａｎｇＪｉａｚｈｅｎ；ＬｕＢｉｎｇａ...     

The characteristics of geophysical field and tectonic evolutionin the Bransfield Strait

ＴｈｅｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｇｅｏｐｈｙｓｉｃａｌｆｉｅｌｄａｎｄｔｅｃｔｏｎｉｃｅｖｏｌｕｔｉｏｎｉｎｔｈｅＢｒａｎｓｆｉｅｌｄＳｔｒａｉｔＹａｏＢｏｃｈｕ（姚伯初）;ＷａｎｇＧｕａｎｇｙｕ（王光宇）;ＣｈｅｎＢａｎｇｙａｎ（陈邦彦）ａ...     

Crust-mantle structure under South Pole and Ross Sea Beach in Antarctica

Ｃｒｕｓｔ－ｍａｎｔｌｅｓｔｒｕｃｔｕｒｅｕｎｄｅｒＳｏｕｔｈＰｏｌｅａｎｄＲｏｓｓＳｅａＢｅａｃｈｉｎＡｎｔａｒｃｔｉｃａＳｈｕＰｅｉｙｉ（束沛镒）ａｎｄＺｈａｎｇＢｏ（张钋）（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ，ＡｃａｄｅｍｉａＳｉｎｉｃ...     

《中国沙漠植物志》厚壁荠属,四棱荠属,菘蓝属和独行菜属订正

通过对中国沙区厚壁荠属ＰａｃｈｙｐｔｅｒｙｇｉｕｍＢｕｎｇｅ、四棱荠属ＧｏｌｄｂａｃｈｉａＤＣ．、菘蓝属ＩｓａｔｉｓＬ．和独行菜属ＬｅｐｉｄｉｕｍＬ．植物的研究,认为《中国沙漠植物志》收录的密花厚壁荠ＰａｃｈｙｐｔｅｒｙｇｉｕｍｄｅｎｓｉｆｌｏｒｕｍＢｕｎｇｅ和多茎厚壁荠Ｐ．ｍｕｌｔｉｃａｕｌｅ（Ｋａｒ．ｅｔＫｉｒ．）Ｂｕｎｇｅ实为一种植物;短梗四棱荠Ｇｏｌｄｂａｃｈｉａｌａｅｖｉｇａｔａ（Ｍ．Ｂ．）ＤＣ．ｖａｒ．ｉｋｏｎｎｉｋｏｖｉ（Ｖａｓｓ．）ＫｕａｎｅｔＹ．Ｃ．Ｍａ应合并到正种四棱荠Ｇ．ｌａｅｖｉｇａｔａ（Ｍ．Ｂ．）ＤＣ．中;毛三肋菘蓝ＩｓａｔｉｓｃｏｓｔａｔａＣ．Ａ．Ｍｅｙｖａｒ．ｌａｓｉｏｃａｒｐａ（Ｌｅｄｅｂ．）Ｎ．Ｂｕｓｃｈ应改为毛果菘蓝Ｉ．ｔｉｎｃｔｏｒｉａＬ．ｖａｒ．Ｐｒａｅｃｏｘ（Ｋｉｔ．）Ｋｏｃｈ．;头花独行菜ＬｅｐｉｄｉｕｍｃａｐｉｔａｔｕｍＨｏｏｋ．ｆ．ｅｔＴｈｏｍｓ．中国沙区无分布。     

A preliminary study on the element strata and palaeoenvironment of core NP95 1 from the Prydz Bay,Antarctica

Ａｐｒｅｌｉｍｉｎａｒｙｓｔｕｄｙｏｎｔｈｅｅｌｅｍｅｎｔｓｔｒａｔａａｎｄｐａｌａｅｏｅｎｖｉ┐ｒｏｎｍｅｎｔｏｆｃｏｒｅＮＰ９５┐１ｆｒｏｍｔｈｅＰｒｙｄｚＢａｙ,ＡｎｔａｒｃｔｉｃａＧｕＳｅｎｃｈａｎｇ（古森昌）ａｎｄＹａｎＷｅｎ（颜文）Ｓｏｕ...     

The observations on Polar Stratospheric Clouds at Zhongshan Station，Antarctica

ＴｈｅｏｂｓｅｒｖａｔｉｏｎｓｏｎＰｏｌａｒＳｔｒａｔｏｓｐｈｅｒｉｃＣｌｏｕｄｓａｔＺｈｏｎｇｓｈａｎＳｔａｔｉｏｎ，ＡｎｔａｒｃｔｉｃａＳｕｎＪｉｎｈｕｉ（孙金辉）；ＸｉａＱｉｌｉｎ（夏其林）；ＱｉｕＪｉｎｈｕａｎ（邱金桓）ａｎｄＬｕＤａｒｅｎ（...     

Self－organization phenomena of the nonequilibrium process in magmatism of the Fildes Peninsula， West Antarctica

（李兆鼐）（李汉声）（尚如相）Ｓｅｌｆ－ｏｒｇａｎｉｚａｔｉｏｎｐｈｅｎｏｍｅｎａｏｆｔｈｅｎｏｎｅｑｕｉｌｉｂｒｉｕｍｐｒｏｃｅｓｓｉｎｍａｇｍａｔｉｓｍｏｆｔｈｅＦｉｌｄｅｓＰｅｎｉｎｓｕｌａ，ＷｅｓｔＡｎｔａｒｃｔｉｃａ￥ＬｉＺｈａｏｎａｉ；Ｌ...     

Analyses on the physio－psychological state of the expeditioners in Antarctica

Ａｎａｌｙｓｅｓｏｎｔｈｅｐｈｙｓｉｏ－ｐｓｙｃｈｏｌｏｇｉｃａｌｓｔａｔｅｏｆｔｈｅｅｘｐｅｄｉｔｉｏｎｅｒｓｉｎＡｎｔａｒｃｔｉｃａＺｈａｎｇＷｅｎｃｈｅｎｇ（张文诚）；ＷｕＷｅｎ（巫雯）ａｎｄＹｕＹｏｎｇｚｈｏｎｇ（于永中）（ＢｅｉｊｉｎｇＩｎ...     

The chemical characteristics of seawater in the Prydz Bay,Antarctica

ＴｈｅｃｈｅｍｉｃａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｓｅａｗａｔｅｒｉｎｔｈｅＰｒｙｄｚ　Ｂａｙ，ＡｎｔａｒｃｔｉｃａＷａｎｇＹｕｈｅｎｇ（王玉衡）；ＤｅｎｇＨｅｎｇｌｉｎｇ（董恒霖）ａｎｄＲｅｎＤｉａｎｙｏｎｇ（任典勇）（ＳｅｃｏｎｄＩｎｓｔｉ...     

Late Quaternary glacial－marine sedimentation in the Bransfield Strait off northeast Antarctic Peninsula

（段威武）（钟和贤）（李扬）ＬａｔｅＱｕａｔｅｒｎａｒｙｇｌａｃｉａｌ－ｍａｒｉｎｅｓｅｄｉｍｅｎｔａｔｉｏｎｉｎｔｈｅＢｒａｎｓｆｉｅｌｄＳｔｒａｉｔｏｆｆｎｏｒｔｈｅａｓｔＡｎｔａｒｃｔｉｃＰｅｎｉｎｓｕｌａ￥ＤｕａｎＷｅｉｗｕ；ＺｈｏｎｇＨｅｘ...     

Record of the younger part of the Pringle Falls excursion at Long Valley, California

The younger of two closely spaced palaeomagnetic excursions at Pringle Falls, Oregon, is recorded in lacustrine silts that crop out in Long Valley, California. Assigned an age of about 220 000 years, the virtual geomagnetic poles of the younger excursion form a clockwise loop that reached 35 °S latitude east of South America before returning to the northern hemisphere in the Pacific Ocean west of Central America. The poles then form a narrow band across North America while moving to high northern latitudes. This record matches extremely well feature B of the original excursion record from Pringle Falls reported by Herrero-Bervera et al. (1994) and is similar to this excursion at Summer Lake, Oregon ( Negrini et al. 1994 ), in that the pole path is confined primarily to the east–central Pacific Ocean. On the basis of an assumed sedimentation rate of 30  cm per thousand years, the younger excursion (feature B at Pringle Falls) spans an estimated 1200 years and followed by about 1000 years a larger excursion (feature A at Pringle Falls) previously discovered at the same Long Valley site. At a second Long Valley site 30  m away, the younger excursion (feature B) is only partially recorded because of a presumed small hiatus in the sedimentary section.     

Two geomagnetic excursions during the Brunhes chron recorded in Chinese loess-palaeosol sediments

Detailed palaeomagnetic integrated with rock magnetic studies have been carried out on a loess-palaeosol sequence in Baoji, Shaanxi province, southern Chinese Loess Plateau. For most samples stepwise thermal demagnetization revealed two well-defined magnetization components. A low-temperature component (LTC), which was isolated between 100 and 200 °C, is consistent with the present geomagnetic field direction. A high-temperature component (HTC), which was isolated between 250 and 620–680 °C, shows normal, reversed or transitional polarities. Our new magnetostatigraphy revealed two distinct geomagnetic excursions recorded in loess unit of L5 and palaeosol unit of S7, respectively, and the Matuyama-Brunhes (M-B) polarity boundary in loess unit of L8. Rock magnetic experiments demonstrated that the specimens from the excursion zones have the same magnetic properties as those from the Brunhes normal or Matuyama reversed polarity zones. Measurements of anisotropy of magnetic susceptibility (AMS) showed that the sediments have primary sedimentary fabrics. Based on the palaeoclimatological and magnetostratigraphic age models, the middle Brunhes excursion in loess L5 is dated at 413–433 ka, and the early Brunhes excursion is estimated to occur 23–33 ka after the M-B reversal. Comparing with previously reported geomagnetic excursions in the Brunhes chron, the middle Brunhes excursion (L5) is likely global. For the early Brunhes excursion (S7), we need further studies to examine its global occurrence.     

Magnetostratigraphic results from the eastern Arctic Ocean: AMS 14C ages and relative palaeointensity data of the Mono Lake and Laschamp geomagnetic reversal excursions

A new high-resolution magnetostratigraphic record from the eastern Arctic Ocean has yielded further evidence for the existence of the Laschamp excursion (37–35  ka), the Mono Lake excursion (27–25.5  ka) and possibly another very short excursion (22  ka) inferred from steep negative inclinations. Ages are based on nine AMS (accelerator mass spectrometry) ¹⁴C dates, oxygen isotope stratigraphy and correlation with ODP site 983. Estimates of relative palaeointensity variations for the time interval from 80 to 10  ka have revealed that the documented geomagnetic excursions are linked to large fluctuations of the relative palaeointensity. The lowest values were obtained for the two excursions and the normal–reversed (N–R) and reversed–normal (R–N) transitions of the Laschamp polarity excursion, which itself is characterized by a slight increase of relative palaeointensity during its reversed state. The results are in general agreement with palaeointensity studies from other regions, indicating that these fluctuations could be global phenomena and that the geomagnetic field of the Brunhes Chron was very variable in amplitude as well as in geometry. The new result is one of the rare records comprising large directional as well as large relative palaeointensity variations.     

南极布兰斯菲尔德海峡沉积物的地磁场长期变与定年

对位于布兰斯菲尔德海峡东北部的沉积物岩心D1-7进行了初步环境磁学和古地磁研究,获得了连续的相对地磁场强度和方向。沉积物岩性总体为灰色软塑性粘土,中下部出现一层黑色火山灰层。结合该孔沉积物和有孔虫AMS¹⁴C测年结果（王汝建等未发表资料）,相对地磁场强度及其方向提供了12 ka以来连续的定年标尺,其中相对地磁场强度与具有相似沉积速率的南美Laguna Potrok Aike湖泊记录对比提供了六个对比点;同时特征剩磁倾角和磁偏角提供了另外六个对比点。磁化率各向异性分析揭示了全新世早、中和晚期岩心所在位置底流（南极深层水~1000 m）发生了阶段性显著变化,同时磁性矿物含量、粒度、沉积物湿密度等也发生了相应的变化。这些环境磁学和沉积学的变化主要受控于南极相应纬度处的太阳辐射量以及与辐射量相关的夏季季风降水量的变化,降水量增加导致磁性矿物粒度变细。D1-7也记录了一些千年尺度旋回变化,但是南极地区目前缺乏与之相似分辨率的气候参数记录,无法进一步探讨这些气候事件的缘起和分布范围。对比发现,地磁场长期变产生的年龄与沉积物全样有机碳AMS¹⁴C测年结果之间存在系统的差异,在6 ka以来比有机碳年龄年轻,在6 ka之前则比有机碳年龄老。南极布兰斯菲尔德海峡内各种不同水体的混合以及在全新世全球升温背景下冰川的动态变化和由此引起的中、深层水变化,都是造成水体性质复杂的原因。而地磁场强度和方向变化则不受水体性质的影响,因此可以提供更合理的年龄信息。自12 ka至今,25 cm/ka的平均沉积速率表明南极布兰斯菲尔德海峡地区整个全新世内稳定和丰富的沉积物供应。     

江苏海安青墩地区新石器时代环境考古

通过对海安青墩遗址剖面进行磁化率、粒度、孢粉、14 C测年等指标分析 ,结果表明 ,剖面第 8层至第 7层是一个海退过程 ,同时微体古生物分析表明这两层均无有孔虫 ,可知当时此区域离海较远。第 8层到第 7层气候向暖湿方向转化 ,良好的气候环境条件为后来该区域人类活动的发展创造了条件。测年资料表明第 6层为距今 3790± 10 5 14 CaB .P .,是大暖期后面的一个气候波动和缓的亚稳定暖湿期 ,当时中国绝大部分地区气候要比现今暖湿。剖面的第 3、 4、 5层 ,即 4 0 0 0 14 CaB .P .以来的一个时期 ,该区出现了一洪水泛滥期 ,正是这一洪水期导致该区域人类文明的衰落。     

毛乌素沙地南缘全新世自然环境

根据毛乌素沙地南縁柳树湾剖面的孢粉分析,结合岩性、¹⁴C测定等资料,揭示该地全新世植物群落的演替,讨论自然环境的变迁。     

RADIOCARBON AGES ON ORGANICS FROM PIEDMONT ALLUVIUM,AJO MOUNTAINS,ARIZONA

Alluvium in dry lands is considered difficult to date by radiocarbon methods because of the paucity of organic matter. Although organic materials of sufficient size for conventional ¹⁴C dating are rare, wet sieving of alluvium in the Sonoran Desert yields sufficient organics for ¹⁴C measurements by accelerator mass spectrometry (AMS). Detrital charcoal from two Quaternary fluvial fill terraces on the western side of the Ajo Mountains yielded ¹⁴C ages of 14,880 ± 70 yr B.P. (CAMS-12408) for the Qt 1 terrace and 2490 ± 60 yr B.P. (CAMS-12414) and 2510 ± 60 yr B.P. (CAMS-12415) for the smaller inset Qt 2 terrace. These ¹⁴C ages are consistent with what is known about rates of soil development in the region. The earlier aggradation event appears to be supported by regional and possibly global climate change at about 14,000 ¹⁴C yr B.P. The more recent aggradation event does not appear to be synchronous with periods of frequent paleofloods in the southwest. The offset between ¹⁴C and ³⁶Cl ages for the same terraces provides a general indication of the time taken for the clasts to be transported to their current positions on the terraces. [Key words: soils, organic matter, 14C, 36Cl, Quaternary dating methods, piedmont, geomorphology, Sonoran Desert.]     

珠江三角洲三水盆地早全新世以来 孢粉分析与古环境重建

为了深入探讨珠江三角洲的沉积古环境和古气候历史,在三水市区获取了2个高取芯率的钻孔岩芯,进行了12个AMS 14C测年,并结合孢粉、硅藻等分析结果探讨三水地区全新世的海平面与河流水动力变化,以及古植被演替过程。结果表明：钻孔所在区域全新世沉积总体从9 000 cal. a B.P.左右开始,呈现河流相―河湾相―河口湾相―潮坪相―河口湾相―河漫滩相的演变过程。三水区的早全新世沉积阶段年代最早为9 000 cal. a B.P.左右,表现为河口湾相的淤泥质粉砂沉积,硅藻以淡水种类为主,最高沉积速率为1.6 cm/a。海侵初始时间为8 700 cal. a B.P.左右,最高海平面时间为7 600 cal. a B.P.左右,此时海岸带发育红树林,丘陵山地发育较茂盛的亚常绿热带常绿阔叶林;中―晚全新世阶段（6 500―2 200 cal. a B.P.）,以泥炭粉砂沉积为主,沉积速率为0.2~0.5 cm/a,河口区高潮线附近及河流弯道低洼滩地在5 000 cal. a B.P.前后形成淡水沼泽、河口三角洲边缘区洼地水松林发育。在晚全新世（2 200 cal. a B.P.左右）以来,陆相黏土质沉积指示河口泥沙快速堆积,三角洲平原迅速扩大,沉积速率高达1.7 cm/a。孢粉结果显示次生的芒箕孢子剧增,陆地植被稀疏,人类活动显著增强。     

南极普里兹湾NP951柱样元素地层与古环境初步研究

对南极普里兹湾ＮＰ９５１柱样的元素地球化学特征及其古环境意义进行了研究。结果表明，本区沉积物在沉积过程中受冰盖消融、淡水涌入和陆源物质的影响较大；沉积物中ＳｉＯ２、Ａｌ２Ｏ３、Ｆｅ２Ｏ３、ＣａＯ、ＭｇＯ、Ｐ、Ｓ、Ｃｏｒｇ等元素组分较好地记录了由古气候变化而引起的物源改变，这些元素组分在地层中的分布规律与古海洋沉积环境及古气候变迁相一致；自晚更新世末期以来的气候大致可分为温暖期、寒冷期、高温期、转冷期和转暖期五个区段；在柱样的１４５ｃｍ（１４．４ｋａＢ．Ｐ．）、８５ｃｍ（１０．３ｋａＢ．Ｐ．）和２５ｃｍ（６．３ｋａＢ．Ｐ．）处出现了古气温的高值点，指示了气候的变化；８５ｃｍ处元素含量的突变指示了异常事件的发生，该层位正好对应于哥德堡地球磁场漂移，全球气温突然变暖，标志着１０．３ｋａＢ．Ｐ．以后南极地区进入了全新世。     

毛乌素沙地北缘泊江海子剖面粒度特征及环境意义

通过毛乌素沙地现代风成沙的粒度与泊江海子剖面沉积物粒度特征对比分析,确定了剖面中4个层位（290—210 cm、190—160 cm 、153.5—123.5 cm、50—40 cm）基本属于风成砂沉积,并且这些风成砂中间夹杂着三次湖相沉积,结合14C年代测定,我们认为此区域在4 000—5 000 a BP存在以下沉积（气候）旋回:至(4 958±84)a BP,沉积风成砂,反映该时期风沙活动强烈,气候干燥,冬季风强盛;(4 958±84)a BP前后,沉积物为灰绿色湖相层,表明这一时期存在短暂的湖面扩展,沙漠退缩;(4 958±84)—(4 793±74)a BP,沉积风成砂,反映了湖泊的退缩和沙漠的扩展;(4 793±74)—(4 536±70)a BP,湖相沉积物,反映了流域降水量的增多;(4 536±70)—(4 085±67)a BP沉积风成砂后,(4 085±67)a BP前后又出现了短暂的湖相沉积,之后又是风成砂沙沉积。