{"title":"软沉积物变形结构或微生物诱导沉积结构:描述和可能的起源","authors":"Kai Lu, Zhidong Bao, Jin Li","doi":"10.1007/s13146-024-00944-7","DOIUrl":null,"url":null,"abstract":"<p>Within the lower Wumishan Formation at the eastern edge of the Tai-hang Mountains in North China, a ~ 10 m stratigraphic interval contains alternately \"bright and dark\" laminites with enigmatic loop structures (2.5–27.5 cm in length and 0.6–12 cm in height), preserved in cross-sectional and named \"loopites\" in this study. The loopites are composed of cores and annulate laminations. Based on the different morphologies, they can be divided into three different types: type I, II and III. Although the loopites are similar to the loop beddings, the formation mechanisms are different. The former is possibly microbially induced sedimentary structures (MISS), while the loop beddings preserve evidence of soft-sediment deformation structures (SSDS) such as boudinage or chain structures, joints and small-scale tensional faults. All three types of loopites have cores. The type I core is made up of relicts of previous microbial mat and the microhighlands, while the type II and III loopites have cores defined by debris and rock fragments. The cores are completely wrapped by microbial mats of later generation. Thus, we can conclude that the formation of loopites is due to the growth, wrapping and deposition of microbial mats, while loop beddings are generated by external triggering mechanism such as earthquake. Furthermore, the discovery and possible formation of loopites may provide a new type of MISS and indicate a stable, anoxic and carbonate-supersaturated environment favorable for microbial mats to form annulate structures, which are controlled by illumination, microtopography and hydrodynamics.</p>","PeriodicalId":9612,"journal":{"name":"Carbonates and Evaporites","volume":"4 1","pages":""},"PeriodicalIF":1.1000,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Soft-sediment deformation structures or microbially induced sedimentary structures: the description and possible origin of the\",\"authors\":\"Kai Lu, Zhidong Bao, Jin Li\",\"doi\":\"10.1007/s13146-024-00944-7\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Within the lower Wumishan Formation at the eastern edge of the Tai-hang Mountains in North China, a ~ 10 m stratigraphic interval contains alternately \\\"bright and dark\\\" laminites with enigmatic loop structures (2.5–27.5 cm in length and 0.6–12 cm in height), preserved in cross-sectional and named \\\"loopites\\\" in this study. The loopites are composed of cores and annulate laminations. Based on the different morphologies, they can be divided into three different types: type I, II and III. Although the loopites are similar to the loop beddings, the formation mechanisms are different. The former is possibly microbially induced sedimentary structures (MISS), while the loop beddings preserve evidence of soft-sediment deformation structures (SSDS) such as boudinage or chain structures, joints and small-scale tensional faults. All three types of loopites have cores. The type I core is made up of relicts of previous microbial mat and the microhighlands, while the type II and III loopites have cores defined by debris and rock fragments. The cores are completely wrapped by microbial mats of later generation. Thus, we can conclude that the formation of loopites is due to the growth, wrapping and deposition of microbial mats, while loop beddings are generated by external triggering mechanism such as earthquake. 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引用次数: 0
摘要
在华北太行山东缘的五味山下统中,一个约 10 米的地层间隙中交替分布着 "明暗 "交替的层理,层理上有神秘的环状结构(长 2.5 至 27.5 厘米,高 0.6 至 12 厘米),断面保存完好,本研究将其命名为 "环纹石"。环状岩由岩芯和环状层理组成。根据形态的不同,它们可分为三种不同类型:I 型、II 型和 III 型。虽然环状岩与环状层理相似,但其形成机制不同。前者可能是微生物诱发的沉积结构(MISS),而环状基底则保留了软沉积变形结构(SSDS)的证据,如包丁状或链状结构、节理和小规模张性断层。这三种类型的圈岩都有岩心。第一类岩芯由以前的微生物垫和微高地遗迹组成,而第二类和第三类圈岩的岩芯则由碎屑和岩石碎片确定。这些岩芯完全被后代的微生物垫所包裹。因此,我们可以得出结论,环状岩的形成是由于微生物垫的生长、包裹和沉积,而环状基底则是由地震等外部触发机制产生的。此外,环状岩的发现和可能形成可能提供了一种新的 MISS 类型,并表明一种稳定、缺氧和碳酸盐过饱和的环境有利于微生物垫形成环状结构,这种结构受光照、微地形和流体力学的控制。
Soft-sediment deformation structures or microbially induced sedimentary structures: the description and possible origin of the
Within the lower Wumishan Formation at the eastern edge of the Tai-hang Mountains in North China, a ~ 10 m stratigraphic interval contains alternately "bright and dark" laminites with enigmatic loop structures (2.5–27.5 cm in length and 0.6–12 cm in height), preserved in cross-sectional and named "loopites" in this study. The loopites are composed of cores and annulate laminations. Based on the different morphologies, they can be divided into three different types: type I, II and III. Although the loopites are similar to the loop beddings, the formation mechanisms are different. The former is possibly microbially induced sedimentary structures (MISS), while the loop beddings preserve evidence of soft-sediment deformation structures (SSDS) such as boudinage or chain structures, joints and small-scale tensional faults. All three types of loopites have cores. The type I core is made up of relicts of previous microbial mat and the microhighlands, while the type II and III loopites have cores defined by debris and rock fragments. The cores are completely wrapped by microbial mats of later generation. Thus, we can conclude that the formation of loopites is due to the growth, wrapping and deposition of microbial mats, while loop beddings are generated by external triggering mechanism such as earthquake. Furthermore, the discovery and possible formation of loopites may provide a new type of MISS and indicate a stable, anoxic and carbonate-supersaturated environment favorable for microbial mats to form annulate structures, which are controlled by illumination, microtopography and hydrodynamics.
期刊介绍:
Established in 1979, the international journal Carbonates and Evaporites provides a forum for the exchange of concepts, research and applications on all aspects of carbonate and evaporite geology. This includes the origin and stratigraphy of carbonate and evaporite rocks and issues unique to these rock types: weathering phenomena, notably karst; engineering and environmental issues; mining and minerals extraction; and caves and permeability.
The journal publishes current information in the form of original peer-reviewed articles, invited papers, and reports from meetings, editorials, and book and software reviews. The target audience includes professional geologists, hydrogeologists, engineers, geochemists, and other researchers, libraries, and educational centers.