(LaCl)(THF)_2(μ-Cl)_4[Li(THF)_2]_2配合物的合成及晶体结构

LaCl_3和LiCl在THF中于室温反应,以已烷为沉淀剂,在-78℃得到晶体,经色谱、元素分析及X射线晶体结构测定,得到了组成为(LaCl)(THF)_2(μ-Cl)_4[Li(THF)_2]_2的配合物.在约-80℃收集该配合物晶体的衍射强度数据,计算结果表明属于单斜晶系,P2_1/c空间群,其晶胞常数a=10.542(4)(?),b=32.236(14)(?),c=11.182(6)(?);β=113.50(3)°,最后R值为0.0477.四个氯桥键构成了分子的基本骨架,表明桥键在小配体轻希土双金属配合物结构中具有稳定作用.

Preservation of black carbon in the shelf sediments of the East China Sea

Concentrations and carbon isotopic (C-14, C-13) compositions of black carbon (BC) were measured for three sediment cores collected from the Changjiang River estuary and the shelf of the East China Sea. BC concentrations ranged from 0.02 to 0.14 mg/g (dry weight), and accounted for 5% to 26% of the sedimentary total organic carbon (TOC) pool. Among the three sediment cores collected at each site, sediment from the Changjiang River estuary had relatively high BC contents compared with the sediments from the East China Sea shelf, suggesting that the Changjiang River discharge played an important role in the delivery of BC to the coastal region. Radiocarbon measurements indicate that the ages of BC are in the range of 6910 to 12250 years old B. P. (before present), that is in general, 3700 to 9000 years older than the C-14 ages of TOC in the sediments. These variable radiocarbon ages suggest that the BC preserved in the sediments was derived from the products of both biomass fire and fossil fuel combustion, as well as from ancient rock weathering. Based on an isotopic mass balance model, we calculated that fossil fuel combustion contributed most (60%. 80%) of the BC preserved in these sediments and varied with depth and locations. The deposition and burial of this "slow-cycling" BC in the sediments of the East China Sea shelf represent a significant pool of carbon sink and could greatly influence carbon cycling in the region.

北黄海西部泥质沉积特征与成因探讨

本文的研究的主要目的是了解北黄海泥质区的沉积特征和形成的动力过程。基于此目的，在北黄海西部海区进行了两次海洋地质与地球物理调查，并根据对浅钻样品的粒度分析和~（210）Pb沉积速率的测定，结合浅地层剖面的解译以及ADCP流速资料的处理，探讨了北黄海西部的沉积层序，讨论了泥质区的物质来源与形成原因，分析了北黄海中部泥质沉积的~（210）Pb沉积速率在一定的动水条件下的可信度，并对柱状样粒度参数的相关分析与地层对比之间的关系进行了初步的阐述。浅地层剖面与岩芯粒度分析表明，北黄海西部的地层划分为三层：上层为粘土沉积，位于北黄海中部、山东半岛沿岸和辽东半岛东南岸；中层为粉砂沉积，分布区域与粘土沉积类似，或者位于粘土沉积之下，或者直接出露海底；下层为粗颗粒砂质沉积，颁上于整个海区，在粘土沉积和/或粉砂沉积存在的海域，砂质沉积位于这些沉积的下部，而在其他海域则直接出露海底。粘土沉积与粉砂沉积统称为泥质沉积，内部结构较均一，粒度的垂向变化不大，但两层之间在粒度和地层反射信号等方面的差异还是很明显的，在山东半岛沿岸构成了泥质沉积的两相结构。粗颗粒沉积的粒度垂向变化较大，与上层细颗粒沉积之间的差异显著。泥质沉积的厚度以山东半岛东端最大，约30m。而沉积速率却很小，在mm/a的量级上，因此在全新世最大海侵后的几千年内形成巨厚的沉积是不可能的，其主要物源可能是古河流。渤海海峡区泥质沉积厚度从南向北、从西向东逐渐变薄，从西向东沉积速率逐渐减小，但沉积速率的绝对值较大，可以在全新世最大海侵后的几千年内形成如此厚的沉积。北黄海中部泥质沉积厚度约在8m左右，位于泥质沉积边缘岩芯中泥炭层的~（14）C年代约10000aBP，而且~（210）Pb沉积速率较小，无法满足几千年内堆积厚层沉积的需要，因此，该处泥质沉积的主体并非全新世最大海侵后形成的，而是早全新世海侵过程中的海岸侵蚀与海底物质的再改造作用提供了沉积物质。整个北黄海西部的泥质沉积总量约有4.41 * 10~（11）t。对于两个沉积环境可能相似的柱状岩芯，利用粒度参数求取各个层位的最大相关系数，可以找到具有良好对应关系的层位，其沉积年龄相近。或者说，在已知一个岩芯的粒度参数和层位年龄的情况下，可以应用柱状样粒度参数的相关分析，推得另一个粒度参数已知的岩芯的年龄。理论上，这种方法适用于来自相同动力环境的岩芯。利用水动力条件与悬沙浓度计算北黄海中部泥质区的沉降通量，与~（210）Pb测得的结果对比，发现对于粘性颗粒两者的值非常近似，说明在该区的动水条件下~（210）Pb测年法对粘性沉积物的测定结果有很好的可信度。

土地利用变化对高寒草甸土壤有机质更新的影响

对青藏高原海北站区的自然土壤和扰动土壤进行高分辨率采样,测定土壤根系、有机碳及其~(14)C含量;用~(14)C示踪技术探讨土地利用变化对高寒草甸土壤有机质更新的影响.研究表明,土地利用变化对高寒草甸土壤碳循环影响显著. 耕作活动导致扰动土壤有机碳储量比自然土壤增加29.35%;扰动土壤剖面10～50 cm深土壤有机质的14C含量相对富集;自然土壤大多数有机碳储存在土壤表层,更新时间＜50 a,同一深度扰动土壤有机碳储量显著少,更新时间长(171～294 a);自然土壤10 cm以下有机碳主要为更新时间＞1 000 a的稳定碳所控制,扰动土壤的相应值出现在40 cm以下;自然土壤有机质更新产生的CO2通量为114 gC•m~(-2)•a~(-1),扰动土壤为48.7 gC•m~(-2)•a~(-1).

HPLC-APCI-MS determination of free fatty acids in Tibet folk medicine Lomatogonium rotatum with fluorescence detection and mass spectrometric identification

A simple and sensitive method for the determination of free fatty acids (FFAs) using acridone-9-ethyl-p-toluenesulfonate (AETS) as a fluorescence derivatization reagent by high performance liquid chromatography (HPLC) has been developed. Free fatty acid derivatives were separated on an Eclipse XDB-C-8 column with a good baseline resolution and detected with the fluorescence of which excitation and emission wavelengths of derivatives were set at lambda(ex) 404 and lambda(em) 440 nm, respectively. Identification of 19 fatty acid derivatives was carried out by online post-column mass spectrometry with an atmospheric pressure chemical ionization (APCI) source under positive-ion detection mode. Nineteen FFAs from the extract of Lomatogonium rotatum are sensitively determined. The results indicate that the plant Lomatogonium rotatum is enriched with an abundance of FFAs and FFAs of higher contents, which mainly focus on even carbon atoms, C-14, C-16, and C-18. The validation of the method including linearity, repeatability, and detection limits was examined. Most linear correlation coefficients for fatty acid derivatives are > 0.9989, and detection limits (at signal-to-noise of 3: 1) are 12.3-43.7 fmol. The relative standard deviations (RSDs) of the peak areas and retention times for 19 FFAs standards are < 2.24% and 0.45%, respectively. The established method is rapid and reproducible for the separation determination of FFAs from the extract of Lomatogonium rotatum with satisfactory results.

黄东海及朝鲜海峡冰后期陆架沉积物的环境磁学研究

There are four chapters in this dissertation. The first chapter briefly synthesizes the basic theories, methods and present-day applying situation of environmental magnetism. The second chapter probes into the magnetic mineral diagenesis in the post-glacial muddy sediments from the southeastern South Yellow Sea and its response to marine environmental changes, using the muddy sediment of Core YSDP103 formed in the shelf since about 13 ka BP. The third chapter illustrates the high-resolution early diagenetic processes by investigating the rapidly deposited muddy sediments during the last 6 ka in Cores SSDP-102 and SSDP-103 from the near-shore shelf of Korea Strait. The fourth chapter presents the results of detailed rock magnetic investigation of the surface sediments from the fine-grained depositional area on the outer shelf of the East China Sea in an attempt to provide environmental magnetic evidence for the provenance of the fine-grained deposit. Core YSDP103 was retrieved in the muddy deposit under the cold eddy of the southeastern South Yellow Sea, and the uppermost 29.79 m core represents the muddy sediments formed in the shelf since about 13 ka BP. The lower part from 29.79 to 13.35 m, called Unit A2, was deposited during the period from the post-glacial transgression to the middle Holocene (at about 6 ~(14)C ka BP) when the rising sea level reached its maximum, while the upper part above 13.35 m (called Unit Al) was deposited in a cold eddy associated with the formation of the Yellow Sea Warm Current just after the peak of post-glacial sea level rise. For the the uppermost 29.79 m core, detailed investigation of rock-magnetic properties and analyses of grain sizes and geochemistry were made. The experimental results indicate that the magnetic mineralogy of the core is dominated by magnetite, maghemite and hematite and that, except for the uppermost 2.35 m, the magnetic minerals were subject to reductive diagenesis leading to significant decline of magnetic mineral content and the proportion of low-coercivity component. More importantly, ferrimagnetic iron sulphide (greigite) is found in Unit A2 but absent in Unit Al, suggesting the control of marine environmental conditions on the magnetic mineral diagenesis. Magnetic parameters show abrupt changes across the boundary between the Unit Al and A2, which reflects a co-effect of environmental conditions and primary magnetic components of the sediments on the diagenesis. Alternating zones of high and low magnetic parameters are observed in Unit A2 of Core YSDP103, which is presumably due to periodic changes of the concentration and/or grain size of magnetic minerals carried into the study area. Cores SSDP-102 and SSDP-103, two studied sediment cores from the Korea Strait contain mud sequences (14 m and 32.62 m in thickness) that were deposited during the last 6,000 years. Analyses of grain sizes and geochemistry of the cores have demonstrated that the sediments have uniform lithology and geochemical properties, however, marked down-core changes in magnetic properties suggest that diagenesis has significantly impacted the magnetic properties. An expanded view of early diagenetic reactions that affect magnetic mineral assemblages is evident in these rapidly deposited continental shelf sediments compared to deep-sea sediments. The studied sediments can be divided into four descending intervals, based on magnetic property variations. Interval 1 is least affected by diagenesis and has the highest concentrations of detrital magnetite and hematite, and the lowest solid-phase sulfur contents. Interval 2 is characterized by the presence of paramagnetic pyrite and sharply decreasing magnetite and hematite concentrations, which suggest active reductive dissolution of detrital magnetic minerals, the absolute minimum abundance of magnetite is reached at the end of this interval. Interval 3 is marked by a progressive loss of hematite with depth, and at the base of this interval, 82% to 88% of the hematite component was depleted and the bulk magnetic mineral concentration was reduced to the lowest value in the entire studied mud section. Interval 4 has an increasing down-core enhancement of authigenic greigite, which is interpreted to have formed due to arrested pyritization resulting from consumption of pore water sulfate with depth. This is the first clear demonstration from an active depositional environment for a delay of thousands of years for acquisition of a magnetization carried by greigite. This detailed view of diagenetic processes in continental shelf sediments suggests that studies of geomagnetic field behavior from such sediments should be conducted with care. Paleoceanographic and paleoclimatic studies based on the magnetic properties of shelf sediments with high sedimentation rates like those in the Korea Strait are also unlikely to provide a meaningful signature associated with syn-depositional environmental processes. The rock magnetic properties of the surface sediments from the fine-grained depositional area on the outer shelf of the East China Sea, an area surrounded by sands, are investigated with a view to providing information on the sediment provenance. Multiple magnetic parameters such as magnetic susceptibility (%), anhysteretic remanent magnetization (ARM), saturation rernanent magnetization (SIRM), coercivities of SIRM (Her), and S ratios (relative abundance of low-coercivity magnetic minerals) are measured for all 179 surface samples, and partial representative samples are examined for their magnetic hysteresis parameters, temperature-dependence of magnetic susceptibility and x-ray diffraction spectra. Our research indicates that the magnetic mineralogy is dominated by magnetite with a small amount of hematite and is primarily of pseudo-single domain (PSD) to multidomain (MD) nature with a detrital origin. In the surface sediments, the granulometry of magnetic fractions is basically independent of grain sizes of the sediment containing the magnetic grains, and the composition of magnetic minerals remains almost homogeneous, that is, with a relatively constant ratio of low to high coercivity fraction throughout the area. The magnetic concentration in the study area generally decreases to the east or southeast accompanied by magnetic-particle fining to the east or to the northeast. The geographic pattern of magnetic properties is most reasonably explained by a major source of sediment jointly from the erosion of the old Huanghe River deposit and the discharge of the Changjiang River. The rock magnetic data facilitate understanding of the transport mechanism of fine-grained sediments in the outer shelf of the East China Sea.

红原泥炭腐殖化度记录的全新世气候变化

腐殖化度作为气候代用指标首次用于我国泥炭的古气候研究,较好的记录了红原地区全新世的气候变化。对红原泥炭14 C 测年和腐殖化度分析,获得了距今12 000 年较高分辨率红原地区气候变化记录:11. 815～10. 9 kaB. P. ,气候干冷;10. 9～5. 6 kaB. P. ,气候湿暖;5. 6～3. 9 kaB. P. ,气候干冷;3. 9～1. 7 kaB. P. ,气候干冷、湿暖波动;1. 7～0 kaB. P. ,气候干冷。总体而言,大约5. 6 kaB. P. 是红原地区由早中全新世的湿暖气候向晚全新世干冷气候变化的转折点。同时,红原泥炭记录的降温事件在北半球具有普遍性,反映了青藏高原对全球气候变化的响应。

江苏固城湖近代沉积物中有机质的组成、演化及其古气候古环境意义

本文对江苏固城湖近代湖相沉积物可溶有机质中正烷烃、甾类、萜类、脂肪酸、醇类、酮类、芳烃等生物标志化合物的组成、分布及其在剖面上的演化进行了详细的研究。首次综合利用有机指标及参数、生物标志物的组成与变化特征，结合磁化率、硅藻、色素、~(14)C年龄推测10200-10600a.B.P.左右一低温突变事件的存在，与氧同位素的对比初步确定这一事件为国外普遍存在的晚仙女木冰期。研究亦表明了固城湖的生物输入具有湖生浮生物及陆生高等植物输入并存的特点；普遍存在的异构及反异构、不饱和脂胞酸、藿烯、蕨烯的存在，表明细菌的活动较为活跃；高含量的具生物构型的ββ藿烷系数、C_(27)-C_(29)甾烯醇、藿烯、蕨烯的存在显示出固城湖沉积有机质尚处于很低的演化阶段，但以C_(30)αβ为主峰及22S > 22R的藿烷分布又表明湖泊有源于周边古老岩石的风化产物；不饱和脂肪酸的与饱和脂肪酸的相对浓度之比C18：2/C18：0、C18：1/C18：0、C16：1/C16：0、TOC含量、C/N随剖面深度增加而降低及C_(27)、C_(29)甾烷醇/甾烯醇随埋深增加而增大表明了早期成岩作用的进行。本文不仅仅在于对湖相沉积物可溶有机质中各组分进行了全面的、详细地分析，更重要的是初次尝试了从有机地化的角度来确定分子标志物、古生物量与突变事件的关系。本研究将为第四纪古气候古环境变迁的研究提供更新的证据、开拓更为广阔的应用前景。

Simple derivatization method for sensitive determination of fatty acids with fluorescence detection by high-performance liquid chromatography using 9-(2-hydroxyethyl)-carbazole as derivatization reagent

A simple and sensitive method for the determination of short and long-chain fatty acids using high-performance liquid chromatography with fluorimetric detection has been developed. The fatty acids were derivatized to their corresponding esters with 9-(2-hydroxyethyl)-carbazole (HEC) in acetonitrile at 60 degreesC with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride as a coupling agent in the presence of 4-dimethylaminopyridine (DMAP). A mixture of esters of C-1-C-20 fatty acids was completely separated within 38 min in conjunction with a gradient elution on a reversed-phase C-18 column. The maximum fluorescence emission for the derivatized fatty acids is at 365 nm (lambda (ex) 335 nm). Studies on derivatization conditions indicate that fatty acids react proceeded rapidly and smoothly with HEC in the presence of EDC and DMAP in acetonitrile to give the corresponding sensitively fluorescent derivatives. The application of this method to the analysis of long chain fatty acids in plasma is also investigated. The LC separation shows good selectivity and reproducibility for fatty acids derivatives. The R.S.D. (n = 6) for each fatty acid derivative are <4%. The detection limits are at 45-68 fmol levels for C-14-C-20 fatty acids and even lower levels for

Effect of dead carbon on the C-14 dating of the speleothem

IEECAS SKLLQG

The sedimentation rates in the Okinawa trough during the Late Quaternary

On the basis of accelerator mass spectrometer radiocarbon (AMS C-14) dating, sedimentation rates of 11 cores collected from the northern to southern Okinawa Trough are discussed. The sedimentation rates in the Okinawa Trough roughly range from 11 to 39 cm/ka, and the average is 23.0 cm/ka. China's continental matter is the main sediment source of the middle Okinawa Trough and has important contribution to the northern and southern Okinawa Trough. The sedimentation rates during the marine oxygen isotope (MI5) 2 are uniformly higher than those during MIS 1 in the northern and middle Okinawa Trough while they are on the contrary in the southern Okinawa Trough. Sedimentation rates in the Okinawa Trough can be one of the proxies of sediment source and an indicator of cooling events.

Manganese abnormity in holocene Sediments of the Bohai Sea

Manganese abnormity has been observed in the Holocene sediments of the mud area of Bohai Sea. On the basis of grain size, chemical composition, heavy mineral content and accelerator mass spectrometry (AMS) C-14 dating of foraminifer, relationships between manganese abnormity and sedimentation rates, material source, hydrodynamic conditions are probed. Manganese abnormity occurred during the Middle Holocene when sea level and sedimentation rates were higher than those at present. Sedimentary hiatus was not observed when material sources and hydrodynamic conditions were quite similar. Compared with the former period, the latter period showed a decrease in reduction environment and an inclination toward oxidation environment with high manganese content, whereas provenance and hydrodynamic conditions showed only a slight change. From the above observations, it can be concluded that correlation among manganese abnormity, material source, and hydrodynamic conditions is not obvious. Redox environment seems to be the key factor for manganese enrichment, which is mainly related to marine authigenic process.