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《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]

卷:

第40卷

期数:

2018年第03期

页码:

275-284

栏目:

基础地质与矿产地质

出版日期:

2018-05-15

文章信息/Info

Title:

High-temperature Experiment on Transformation from Aragonite to Calcite in Land Snail Shells and Its Impact on Carbon Isotope Composition Variations

文章编号:

1672-6561(2018)03-0275-10

作者:

李成龙; 盛雪芬; 鲍睿; 罗铃; 季峻峰

1.南京大学 地球科学与工程学院，江苏 南京 210023； 2.南京大学 表生地球化学教育部重点实验室，江苏 南京 210023

Author(s):

LI Cheng-long;  SHENG Xue-fen;  BAO Rui;  LUO Ling;  JI Jun-feng

1. School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, Jiangsu, China; 2. Key Laboratory of Surficial Geochemistry of Ministry of Education, Nanjing University, Nanjing 210023, Jiangsu, China

关键词:

生物地球化学; 蜗牛; 高温加热; 文石; 方解石化; 双氧水处理; 碳同位素组成; 古气候重建

Keywords:

biogeochemistry;  snail;  high-temperature heating;  aragonite;  calcilization;  H₂O₂ treatment;  carbon isotope composition;  paleoclimate reconstruction

分类号:

P593

DOI:

-

文献标志码:

A

摘要:

在过去全球气候变化研究中，生物CaCO₃壳体的稳定同位素组成是常见的古气候替代性指标，被用来重建古气候变化历史，而生物成因文石质矿物的方解石化则是自然界较为常见的现象，该过程会导致生物壳体稳定同位素组成发生改变，从而影响古气候重建的准确性。利用陆生蜗牛Achatina fulica的文石壳体在空气背景下进行高温加热实验，来揭示加热前后样品中方解石含量和碳同位素组成的变化。结果表明：随着温度的升高，方解石含量增高；文石方解石化过程受壳体有机质含量的影响，相同加热温度和时间条件下，未采用双氧水处理的方解石含量比采用双氧水处理的方解石含量低；高温加热的壳体样品比原始样品碳同位素组成偏负；较短时间实验条件下，温度对文石方解石化过程起主导作用，并且双氧水处理也会对文石方解石化有所影响；造成样品碳同位素组成偏负可能是因为加热过程中样品与空气CO₂发生了碳同位素交换反应，而不是因为矿物相变。因此，在利用蜗牛壳体碳同位素组成进行古环境重建时，需考虑文石方解石化过程对壳体碳同位素组成变化的影响。

Abstract:

The stable isotope compositions of biogenic calcium carbonate are often used as an important proxy for the studies of past global climate change; however, a significant isotope bias during the transformation from aragonite to calcite would affect the quantitative reconstruction of paleoclimate. The experiments were conducted under the air conditions by high-temperature heating the aragonite shells of land snail Achatina fulica, and the various of contents of calcite and carbon isotope compositions before and after heating were revealed. The results show that the contents of calcite increase with the temperature increasing; the transformation from aragonite to calcite is affected by the content of organic matter of the shells; the contents of calcite are lower in the samples without H₂O₂ treatment than those in the samples with H₂O₂ treatment under the condition of the same heating temperature and time; the heating process can cause the samples with lower carbon isotope compositions than the original samples; the temperature in the short-time heating plays an important role in the transformation from aragonite to calcite, and the H₂O₂ could play a role in the transformation; the lower carbon isotope compositions in the heated samples could be due to the carbon isotope exchange reaction between the samples and CO₂ in the air, not due to the phase transformation. Hence, the isotope bias induced by phase transformation and isotope exchange should be taken into consideration when the carbon isotope compositions of land snail shells are used to reconstruct paleoclimatic history.

参考文献/References:

-

相似文献/References:

[1]吴艳宏,罗朝逸,王治国,等.贡嘎山冰川退缩区土壤-植物-微生物功能多样性对磷循环的协同作用[J].地球科学与环境学报,2023,45(03):696.[doi:10.19814/j.jese.2022.12055]
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备注/Memo

备注/Memo:

收稿日期:2017-12-26;修回日期:2018-03-19
基金项目:国家自然科学基金项目(41373091,41073065);国家自然科学基金创新研究群体项目(41321062)
作者简介:李成龙(1992-),男,吉林松原人,理学硕士研究生,E-mail:771494349@qq.com。
通讯作者:盛雪芬(1970-),女,浙江黄岩人,副教授,理学博士,E-mail:shenxuer@nju.edu.cn。

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更新日期/Last Update: 2018-06-05