鄂尔多斯盆地侏罗纪煤中古野火事件及其对古气候的影响  

Wildfires in Jurassic Coal Seams from Ordos Basin and its impact on Paleoclimate

作　　者：许云[1] 张宁 赵存良[1] 梁汉东[3] 孙玉壮[1] XU Yun;ZHANG Ning;ZHAO Cunliang;LIANG Handong;SUN Yuzhuang(Key Laboratory of Resource Exploration Research of Hebei,Hebei University of Engineering,Handan 056038,Hebei,China;First Exploration Bureau,China National Administration of Coal Geology,Handan 056004,Hebei,China;State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology(Beijing),Beijing 100083,China)

机构地区：[1]河北工程大学河北省资源勘测研究重点实验室,河北邯郸056038 [2]中国煤炭地质总局第一勘探局地质勘查院,河北邯郸056004 [3]中国矿业大学(北京)煤炭资源与安全开采国家重点实验室,北京100083

出　　处：《中国地质》2022年第2期643-654,共12页Geology in China

基　　金：国家自然科学基金(41872173);河北省自然科学基金(D2021402030)联合资助。

摘　　要：【研究目的】野火是陆地生态系统的一个重要组成部分,燃烧产生的温室气体会对气候环境产生影响。对地史时期古野火的研究可以获得野火对生态系统的潜在长期影响。【研究方法】采集了鄂尔多斯盆地侏罗纪延安组5个主采煤层的56个样品,并对其进行了宏观煤岩观察、煤岩显微组分定量、惰质组反射率测定、微观形貌观察。【研究结果】结果显示在煤层的顶底板中存在大量的宏观化石木炭(Charcoal),且细胞间层均为同质化;煤中惰质组含量分布范围为45.23%~56.81%,且大部分惰质组反射率低于2%。【结论】这表明在泥炭沉积时期发生过高频率的野火事件且以中低温的地表火为主。根据现代森林火灾碳排放模型和煤中的惰质组由燃烧成因理论,计算出仅在鄂尔多斯盆地延安组泥炭系统中野火释放的总碳量为443 Gt,其中CO_(2)的量为1377 Gt,CO的量为86.7 Gt,CH_(4)的量为8.2 Gt,CO_(2)的释放量相当于目前大气圈中CO_(2)总量的45.9%。延安组时期陆地生态系统中野火释放的巨量温室气体可能是导致这一时期气候变暖的原因之一。This paper is the result of coalfield geological survey engineering.[Objective]Wildfire is an important part of the earth system.The greenhouse gases produced by combustion will have an impact on the climate and the biosphere.One way to obtain information about the potential long term influences of wildfires on ecosystems and the climate system itself is to study palaeo-wildfires.[Methods]A total of 56 Jurassic coal samples from 5 main coal seams were collected from Northern Ordos Basin.The samples were analyzed by macropetrography,microscope,scanning electron microscope in order to study the evidences of wildfire and their impact on the paleoclimate.[Results]The results showed that a great deal of charcoal has been found in the roof and floor of the middle Jurassic coal from Ordos Basin and the cell walls of charcoal observed under SEM were homogenized.The average proportions of inertinite in the coal samples ranged from 45.23%to 56.81%,and the reflectance of most inertinite in coal is less than 2%,which indicated that the frequency wildfires occurred during the peat deposition period and the fires type were dominated by surface and ground fires with low temperature.[Conclusions]According to a carbon emission model for modern forest fires,the total carbon and gas emissions from wildfires in peat swamps of the Middle Jurassic in Northwest China were calculated.The total carbon released from peat-swamp forest wildfires was at least 443 Gt,corresponding to emissions of CO_(2),CO and CH_(4) of 1377 Gt,86.7 Gt,and 8.26 Gt,respectively.The large amount of greenhouse gases released by wildfires may lead to changes of the atmospheric,which may have accelerated the process of climate warming in the Middle Jurassic.

关 键 词：CO_(2)排放 古野火 煤炭 煤田 侏罗纪 古气候 煤炭勘查工程 鄂尔多斯盆地 

分 类 号：P534.52[天文地球—古生物学与地层学] P618.11[天文地球—地质学]