古地理学报 ›› 2021, Vol. 23 ›› Issue (2): 405-420. doi: 10.7605/gdlxb.2021.02.017

• 岩相古地理学及沉积学 • 上一篇    下一篇

德国北部盆地晚侏罗世沉积环境及古气候分析*

白华青1, 旷红伟1, 柳永清1, 吴峰2   

  1. 1中国地质科学院地质研究所,北京 100037;
    2河海大学海洋学院,江苏南京 210098
  • 收稿日期:2020-05-03 修回日期:2020-09-30 出版日期:2021-04-01 发布日期:2021-03-29
  • 作者简介:白华青,女,1985年生,博士后,主要从事沉积学研究。E-mail: huaqing.bai@outlook.com。
  • 基金资助:
    *国家重点研发计划专项(编号: 2016YFC0601001,2018YFC0604201)、国家自然科学基金项目(编号: 41472082)、中国地质调查局项目(编号: DD20190002,DD20190005)共同资助

Sedimentary environments and palaeoclimate of the upper Jurassic deposits in the North German Basin

Bai Hua-Qing1, Kuang Hong-Wei1, Liu Yong-Qing1, Wu Feng2   

  1. 1 Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;
    2 College of Oceanography,Hohai University,Nanjing 210098,China
  • Received:2020-05-03 Revised:2020-09-30 Online:2021-04-01 Published:2021-03-29
  • About author:Bai Hua-Qing,born in 1985,is a postdoctor in the Institue of Geology,CAGS. She is mainly engaged in sedimentology. E-mail: huaqing.bai@outlook.com.
  • Supported by:
    Co-funded by the National Key Research and Development Program of China(Nos.2016YFC0601001,2018YFC0604201),the National Natural Science Foundation of China(No.41472082),China Geological Survey Projects(Nos.DD20190002,DD20190005)

摘要: 德国北部盆地上侏罗统广泛发育,但野外露头地层普遍出露不全。Hildesheimer Wald地区Wendhausen 6井和Süntel山地区Eulenflucht 1井完整钻遇了上侏罗统牛津阶和启莫里阶地层,为分析该区晚侏罗世沉积演化过程及其所反映的古环境变化规律提供了丰富的资料。通过岩心描述和岩石薄片镜下观察,根据不同层段的颗粒成分、生物组合特征、沉积结构和构造等特征,在2口井的岩心中共划分出14个岩石类型,分别形成于碳酸盐岩斜坡和三角洲环境。建立了该区牛津阶和启莫里阶垂向沉积演化序列,垂向上由Heersum组到Süntel组,沉积环境逐步由外陆棚、内陆棚、临滨过渡到了开阔台地、潮坪环境,表现出了相对海平面降低的进积过程。同时对不同沉积相中保存较好的以低镁方解石为主要成分的牡蛎壳进行原位Mg/Ca值(古温度指标)测试,得出该区牛津期至启莫里期总体表现出了古气候变暖的趋势,且共有3次气候变暖过程。这一古气候变化与由沉积相分析得出的古气候变化一致,且同苏格兰、俄罗斯台地古温度变化趋势有很好的对应关系,表明古气候是控制该区沉积演化的一个重要因素,且牡蛎壳Mg/Ca值可以做为一个古气候指示指标应用于其他地区的古气候分析中。

关键词: 岩石类型, 沉积环境, 古气候, 晚侏罗世, 德国北部盆地

Abstract: In the North German Basin,outcrops consisting of the upper Jurassic deposits are widely spread throughout the basin. However,most of them only cover part of the upper Jurassic succession. The drilled Eulenflucht 1 and Wendhausen 6 cores,located in the Süntel and Hildesheimer Wald,respectively,consisting of the Oxfordian and Kimmeridgian deposits,provide valuable data for analyzing the upper Jurassic depositional history and the palaeoclimate variations in North German Basin. Via core description and microscopic observation,14 rock types are identified based on their distinctive grain compositions,fossil associations,and sedimentary texture and structures. They are interpreted to be formed either in carbonate ramp or deltaic environment. A sedimentary succession of the Oxfordian and Kimmeridgian deposits is established showing facies variations. From the Heersum to Süntel Formation,the sedimentary environment changes from outer shelf,inner shelf,and shoreface to open platform restricted lagoon,and tide flat,showing a trend of relative sea-level fall. Mg/Ca values of the well-preserved oyster shells composed of low-magnesium calcite are measured to reflect the palaeoclimate changes. Generally,it shows a warming trend from the Oxfordian to Kimmeridgian,among which three warm intervals are distinguished. These signals of palaeoclimate variations are not only consistent with the palaeoclimate changes obtained from facies analysis,but also comparable with the palaeotemperature fluctuations in Scotland and Russian Platform,suggesting that(1)palaeoclimate change played a controlling role during the upper Jurassic sedimentary evolution in the North German Basin,and(2)the Mg/Ca values of oyster shells can be used as a valid palaeoclimate proxy for analyzing palaeoclimate in other areas.

Key words: rock types, sedimentary environment, palaeoclimate, upper Jurassic, North German Basin

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