广西北部山地沼泽20 ka以来的
碳同位素组成与气候变化

doi:10.13284/j.cnki.rddl.002839

摘要/Abstract

摘要： 根据广西北部山地泥炭沼泽沉积的有机碳同位素组成、TOC和C/N等古气候指标对末次盛冰期以来该区植被与气候演变过程进行研究，结果发现：末次盛冰期（21―14 cal. ka B.P.）偏正的δ13Corg数据反映了山地植被面貌曾发生显著变化，指示冰期气候的冷干变化，但并未导致山地森林向地带性草地退化，C3植物仍占优势。沉积物岩性和TOC等数据表明：在14―10 cal. ka B.P.期间沼泽湿地逐渐形成，指示了东亚夏季风降雨的增强，与石笋指示的季风增强起始年代基本一致。冰消期碳同位素曲线负偏的变化要早于TOC指示的泥炭沼泽堆积，即10―9 cal. ka B.P.前后富有机质的泥炭堆积进入旺盛期。碳同位素组成在9―8 cal. ka B.P.存在一个正偏的变化波动，可能与8.2 ka降温事件或局地物源输入变化有关。7.0―2.8 cal. ka B.P.期间古田湿地的有机质输入较高，碳同位素偏负，指示气候暖湿。从1.7 cal. ka B.P.至今，δ13Corg值的再次正偏可能指示夏季风强度减弱，但考虑到该阶段为人类农业活动快速发展期，因此不排除人为因素的影响。此外，末次盛冰期广西山地与雷州半岛沿海低地的碳同位素值对比发现：沿海平原区与华南山地的沉积记录存在明显差别，其主要原因是山区因山地降雨效应使山区的湿度即便在盛冰期也能保持较高水平；而低地平原冰期阶段的降雨则显著减少，加上平原区较高的蒸发量使干旱程度增加，C4草本也相应增多。实际上，影响亚热带山地沼泽δ13Corg值变化的原因比较复杂，在利用δ13Corg值推论古气候时需要同时考虑气候因素和湿地沉积体的物源及其地貌环境等背景。

关键词: 稳定碳同位素, 气候变化, 亚热带, 泥炭沉积, 广西古田

Abstract: This study concerns the organic carbon isotopes, TOC and C/N in a mountainous peat bog in northern Guangxi province. Result reveals the local vegetation variations and the climate changes since the LGM in subtropical China. Positive δ13Corg indicates vegetation types change due to the cold and dry climate during the LGM. However, cold and dry condition didn’t lead to vegetation degradation from forest to grassland even during the last glacial period, as δ13Corg shows the dominance of C3 plants around the mountains, which is also proved by pollen records. It can be inferred from the lithology and TOC that local peat-land began to accumulate during the period of 14-10 cal. ka B.P., which developed at fastest speed between 10 and 9 cal. ka B.P. Carbon isotope change towards negative values occurred slightly earlier than the formation of the swamp, indicating that strengthening of summer monsoon occurred at about 14 cal. ka B.P., which is basically concordant with the record from stalagmites. Obvious variation in carbon isotopes which occurred between 9-8 cal. ka B.P. may be relative to 8.2 ka cooling event or changes of organic matter sources. High input of organic matter and negative carbon isotopes in the period during 7.0-2.8 cal. ka B.P. corresponded to the wet and warm condition. Relatively positive change of δ13Corg at 1.7 cal. ka B.P. might be caused by prehistory human impact. The comparison between the δ13Corg data and those of the coastal lowland records from the Leizhou Peninsula shows that a big difference existed between plain and mountainous areas, probably because humidity didn’t reduce too much due to the effect of orographic precipitation in the mountains even during the LGM, while decrease in precipitation and high evaporation were apparently shown in the plains. It should be pointed out that the factors are quite complicated for the interpretation of δ13Corg values in the peat records. The changes in sediment environment, origin of the organic matter and geomorphologic conditions should be taken into consideration when using δ13Corg to reconstruct paleoclimate.

Key words: stable carbon isotope, climate change, subtropical, peat deposit, Gutian of Guangxi

满美玲，郑卓，李杰，王梦媛．. 广西北部山地沼泽20 ka以来的碳同位素组成与气候变化[J]. 热带地理, 2016, 36(3): 468-476.

MAN Meiling，ZHENG Zhuo，LI Jie，WANG Mengyuan．. Carbon Isotope Compositions and Climate Changes of the Past 20,000 Years Inferred from a Mountainous Peat Bog of Northern Guangxi [J]. TROPICAL GEOGRAPHY, 2016, 36(3): 468-476.

参考文献

[1] STUIVER M．Climate versus changes in 13C content of the organic component of lake sediments during the Late Quarternary[J]．Quaternary Research，1975，5（2）：251-262．

[2] TAREQ S M，KITAGAWA H，OHTA K．Lignin biomarker and isotopic records of paleovegetation and climate changes from Lake Erhai，southwest China，since 18.5 ka B P[J]．Quaternary International，2011，229（1）：47-56．

[3] FUHRMANN A，MINGRAM J，LüCKE A，LU H，HORSFIELD B，LIU J，NEGENDANK J F，SCHLESER G H，WILKES H．Variations in organic matter composition in sediments from Lake Huguang Maar（Huguangyan），South China during the last 68 ka：implications for environmental and climatic change[J]．Organic Geochemistry，2003，34（11）：1497-1515．

[4] ENGEL Z，SKRZYPEK G，CHUMAN T，?EFRNA L，MIHALJEVI? M．Climate in the western cordillera of the central Andes over the last 4300 years[J]．Quaternary Science Reviews，2014，99：60-77．

[5] CHAWCHAI S，CHABANGBORN A，FRITZ S，V?LIRANTA M，M?RTH C，BLAAUW M，REIMER P J，KRUSIC P J，L?WEMARK L，WOHLFARTH B．Hydroclimatic shifts in Northeast Thailand during the last two millennia–the record of Lake Pa Kho[J]．Quaternary Science Reviews，2015，111：62-71．

[6] HONG Y T，HONG B，LIN Q H，ZHU Y X，SHIBATA Y，HIROTA M，UCHIDA M，LENG X T，JIANG H B，XU H．Correlation between Indian Ocean summer monsoon and North Atlantic climate during the Holocene [J]．Earth and Planetary Science Letters，2003，211（3）：371-380．

[7] 马春梅，朱诚，郑朝贵，武春林，关勇，赵志平，黄林燕，黄润．晚冰期以来神农架大九湖泥炭高分辨率气候变化的地球化学记录研究[J]．科学通报，2008（S1）：26-37．

[8] WEI Z，JIBIN X，JIXIU C，YANMING Z，QIAOHONG M，JUN O，YING C，ZHIGUO Z，WEI L．Bulk organic Carbon isotopic record of lacustrine sediments in Dahu Swamp，eastern Nanling Mountains in South China：Implication for catchment environmental and climatic changes in the last 16,000 years[J]．Journal of Asian Earth Sciences，2010，38（3）：162-169．

[9] ZHENG Z，LEI Z．A 400,000 year record of vegetational and climatic changes from a volcanic basin，Leizhou Peninsula，southern China [J]．Palaeogeography，Palaeoclimatology，Palaeoecology，1999，145（4）：339-362．

[10] ZHONG W，XUE J，OUYANG J，ZHENG Y，MA Q，YU X．Last glacial climate variations on the tropical Leizhou Peninsula，South China [J]．Journal of Paleolimnology，2010，44（3）：777-788．

[11] 朱彪，陈安平，刘增力，李光照，方精云．广西猫儿山植物群落物种组成、群落结构及树种多样性的垂直分布格局[J]．生物多样性，2004，12（1）：44-52．

[12] COOK C G，LENG M J，JONES R T，LANGDON P G，ZHANG E．Lake ecosystem dynamics and links to climate change inferred from a stable isotope and organic palaeorecord from a mountain lake in southwestern China（ca. 22.6-10.5 cal ka BP）[J]．Quaternary Research，2012，77（1）：132-137．

[13] POLONA V，GREGOR M．Sediment organic matter in mountain lakes of north-western Slovenia and its stable isotopic signatures：records of natural and anthropogenic impacts[J]．Hydrobiologia，2010，648（1）：35-49．

[14] MEYERS P A．Preservation of elemental and isotopic source identification of sedimentary organic matter[J]．Chemical Geology，1994，114（3）：289-302．

[15] HASSAN K M，SWINEHART J B，SPALDING R F．Evidence for holocene environmental change from C/N ratios，and δ13C and δ15N values in Swan Lake sediments，western sand hills，Nebraska[J]．Journal of Paleolimnology，1997，18（2）：121-130．

[16] KAUSHAL S，BINFORD M W．Relationship between C：N ratios of lake sediments，organic matter sources，and historical deforestation in Lake Pleasant，Massachusetts，USA[J]．Journal of Paleolimnology，1999，22（4）：439-442．

[17] MACKIE E A，LENG M J，LLOYD J M，ARROWSMITH C．Bulk organic δ13C and C/N ratios as palaeosalinity indicators within a Scottish isolation basin[J]．Journal of Quaternary Science，2005，20（4）：303-312．

[18] MAYR C，LüCKE A，MAIDANA N I，WILLE M，HABERZETTL T，CORBELLA H，OHLENDORF C，SCH?BITZ F，FEY M，JANSSEN S．Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike（southern Patagonia，Argentina） reflect environmental changes during the last 16,000 years[J]．Journal of Paleolimnology，2009，42（1）：81-102．

[19] KRISHNAMURTHY R V，BHATTACHARYA S K，KUSUMGAR S．Palaeoclimatic changes deduced from 13C/12C and C/N ratios of Karewa lake sediments，India[J]．Nature，1986，323：150-152．

[20] MEYERS P A，ISHIWATARI R．Organic matter accumulation records in lake sediments[M]．Berlin：Springer，1995：279-328．

[21] JI S，XINGQI L，SUMIN W，MATSUMOTO R．Palaeoclimatic changes in the Qinghai Lake area during the last 18,000 years[J]．Quaternary International，2005，136（1）：131-140．

[22] SMITH B N，EPSTEIN S．Two categories of 13C/12C ratios for higher plants[J]．Plant Physiology，1971，47（3）：380-384．

[23] 中国科学院北京植物研究所植物生理化研究室．植物生理生化译丛[M]．北京：科学出版社，1974．

[24] LI J，ZHENG Z，HUANG K，YANG S，CHASE B，VALSECCHI V，CARRé M，CHEDDADI R．Vegetation changes during the past 40,000 years in Central China from a long fossil record[J]．Quaternary International，2013，310：221-226．

[25] 李杰．中国亚热带山地泥炭古环境记录：晚第四纪植被与气候重建[D]．广州：中山大学，2012．

[26] SUKUMAR R，RAMESH R，PANT R K，RAJAGOPALAN G．A δ13C record of late Quaternary climate change from tropical peats in southern India[J]．Nature，1993，364（6439）：703-706．

[27] 吴敬禄，王苏民．湖泊沉积物中有机质碳同位素特征及其古气候[J]．海洋地质与第四纪地质，1996，16（2）：103-109．

[28] WANG S，Lü H，LIU J，NEGENDANK J F．The early Holocene optimum inferred from a high-resolution pollen record of Huguangyan Maar Lake in southern China[J]．Chinese Science Bulletin，2007，52（20）：2829-2836．

[29] ZHONG W，XUE J，OUYANG J，TANG X，YIN H，LIAO C，LONG K．Late holocene monsoon climate as evidenced by proxy records from a lacustrine sediment sequence in western Guangdong，South China [J]．Journal of Asian Earth Sciences，2014，80：56-62．

[30] WANG Y，CHENG H，EDWARDS R L，KONG X，SHAO X，CHEN S，WU J，JIANG X，WANG X，AN Z．Millennial-and orbital-scale changes in the East Asian monsoon over the past 224,000 years [J]．Nature，2008，451（7182）：1090-1093．

[31] DYKOSKI C A，EDWARDS R L，CHENG H，YUAN D，CAI Y，ZHANG M，LIN Y，QING J，AN Z，REVENAUGH J．A high-resolution，absolute- dated Holocene and deglacial Asian monsoon record from Dongge Cave，China[J]．Earth and Planetary Science Letters，2005，233（1）：71-86．

[32] ZHOU W，YU X，JULL A T，BURR G，XIAO J Y，LU X，XIAN F．High-resolution evidence from southern China of an early Holocene optimum and a mid-Holocene dry event during the past 18,000 years [J]．Quaternary Research，2004，62（1）：39-48．

[33] XUE J，ZHONG W，ZHENG Y，MA Q，CAI Y，OUYANG J．A new high-resolution Late Glacial-Holocene climatic record from eastern Nanling Mountains in South China[J]．Chinese Geographical Science，2009，19（3）：274-282．

[34] 陈践发，徐永昌．沼泽环境中有机质碳同位素组成特征[J]．科学通报，1992（22）：2080-2082．

[35] GROOTES P M，STUIVER M，WHITE J，JOHNSEN S，JOUZEL J．Comparison of Oxygen isotope records from the GISP2 and GRIP Greenland ice cores[J]．Nature，1993，366：552-554．

[36] ZHENG Z，WANG J，WANG B，LIU C，ZOU H，ZHANG H，DENG Y，BAI Y．High-resolution records of Holocene from the Shuangchi Maar lake in Hainan Island[J]．Chinese Science Bulletin，2003，48（5）：497-502．

[37] 马振兴，黄俊华，魏源，李均辉，胡超涌．鄱阳湖沉积物近8 ka来有机质碳同位素记录及其古气候变化特征[J]．地球化学，2004，33（3）：279-285．

[38] 文雪峰，魏晓，杨瑞东，田明中．贵州龙里高山草原泥炭沉积年代、速率及其有机碳同位素记录[J]．现代地质，2012，26（4）：712-715．

[39] 杨桂芳，黄俊华，谢树成，胡超涌，戴晴，葛之亮．天目山泥炭有机碳同位素特征及其古环境意义[J]．地球学报，2008，29（6）：778-782．

[40] 丁平，沈承德，王宁，易惟熙，丁杏芳，付东坡，刘克新．广东四会古森林地下生态系统碳同位素组成及其古气候意义[J]．中国科学（D辑：地球科学），2009，39（1）：70-78．

[41] LU H，WU N，GU Z，GUO Z，WANG L，WU H，WANG G，ZHOU L，HAN J，LIU T．Distribution of Carbon isotope composition of modern soils on the Qinghai-Tibetan Plateau[J]．Biogeochemistry，2004，70（2）：275-299．

[42] 张慧文．天山现代植物和表土有机稳定碳同位素组成的海拔响应特征[D]．兰州：兰州大学，2010．

[43] 朱书法．贵州典型陆地生态系统土壤中有机碳含量及碳同位素组成[D]．贵阳：中国科学院地球化学研究所，2006．

[44] 旺罗，吕厚远，吴乃琴，吴海斌，刘东生．青藏高原现生禾本科植物的δ13C与海拔高度的关系[J]．第四纪研究，2003，23（5）：573-580．

[45] HULTINE K R，MARSHALL J D．Altitude trends in conifer leaf morphology and stable Carbon isotope composition[J]．Oecologia，2000，123（1）：32-40．

[46] ZHOU Y，FAN J，ZHONG H，ZHANG W．Relationships between altitudinal gradient and plant Carbon isotope composition of grassland communities on the Qinghai-Tibet Plateau，China[J]．Science China Earth Sciences，2013，56（2）：311-320．

[47] 万日金，吴国雄．江南春雨的时空分布[J]．气象学报，2008，66（3）：310-319．

[48] 万日金，赵兵科，应明．高原和山脉地形对长江中下游梅雨形成的影响[J]．高原气象，2009，28（2）：299-305．

[49] 黄晓梅，简茂球，刘桂兴．雷州半岛干旱的特征及其环流分析[J]．广东气象，2013，35（3）：20-24．

[50] 殷立娟，李美荣．中国C4植物的地理分布与生态学研究Ⅰ. 中国C4植物及其与气候环境的关系[J]．生态学报，1997，17（4）：16-29．

[51] LI J，WANG G，LIU X，HAN J，LIU M，LIU X．Variations in Carbon isotope ratios of C3 plants and distribution of C4 plants along an altitudinal transect on the eastern slope of Mount Gongga[J]．Science in China Series D：Earth Sciences，2009，52（11）：1714-1723．