Topographic control on distribution of modern microbially induced sedimentary structures (MISS): A case study from Texas coast     

Sushanta Bose  Henry S. Chafetz 《Sedimentary Geology》2009,213(3-4):136-149

Modern back-barrier tidal flats of Galveston Island, Follets Island, and Matagorda Peninsula of the Texas coast are dominated by mud- to fine sand-sized siliciclastic sediments and prolific microbial mats. These microbial mats modify sediment behavior and result in a variety of microbially induced sedimentary structures (MISS). Common structures include: knobby surfaces, reticulated surfaces, gas domes, mat-cracks, sieve-like surfaces, erosional pockets, wrinkles, and mat chips. In general, mat thicknesses increase from ～ 1 mm in the upper supratidal to ～ 3 cm (maximum) in the lower supratidal and then decrease to ～ 2 mm in the lower intertidal areas. This same wedge-shaped pattern is displayed by detailed measurements of mat thicknesses from the rims into the deeper centers of depressions (pools) on the supratidal flats. Measurements of 175 mat-cracks show that height of the curled edges of the mat-crack polygons increases with increase in mat thickness. Similarly, measurements of 150 gas domes reveal that the size of the gas domes also increases with increasing thickness of the associated mats. Because mat thickness varies with elevation on the tidal flat, curl height of the mat-cracks and size of the gas domes are also related to elevation.Six zones were identified based on the occurrence of MISS within the supratidal (zone-I) to upper subtidal (zone-VI) areas. At the highest elevation, knobby surfaces characterize zone-I whereas zone-II is defined by reticulated surfaces. Along with reticulated surfaces, gas domes and mat-cracks characterize zone-III and zone-IV, respectively. Association of sieve-like surfaces with mat-cracks typifies zone-V whereas mat deformation structures and sieve-like surfaces define zone-VI. Boundaries between the MISS-zones in general are parallel and related to tidal zones. The distribution patterns of the MISS-zones are strongly controlled by local topography of the sediment surface because the degree of inundation is the primary controlling factor for the mat growth and resultant MISS. Therefore, distribution of the microbially induced sedimentary structures in siliciclastics, along with the dimension of the mat-cracks and gas domes, can be potentially helpful in interpretation of topography of paleodepositional surfaces.  相似文献   

Rapid dissipation of a Loop Current eddy due to interaction with a severe Gulf of Mexico hurricane     

Potter  Henry  Hsu  Chuan-Yuan  DiMarco  Steven F. 《Ocean Dynamics》2021,71(9):911-922

Ocean Dynamics - Loop Current Eddies (LCEs) are warm-core, anticyclonic rings that shed from the Loop Current and migrate westward providing kinetic and potential energy to the Gulf of...  相似文献   

Evidence for non-hydrostatic gas from the cluster X-ray to lensing mass ratio     

A. Mahdavi  H. Hoekstra †  A. Babul  J. P. Henry 《Monthly notices of the Royal Astronomical Society》2008,384(4):1567-1574

  相似文献   

奔向全球的经济地理:战略耦合与全球生产网络研究——"全球生产网络与中国战略耦合"专辑序言     

楊偉聰  刘逸 《地理研究》2021,40(12):3253-3258

进入21世纪以来,全球生产网络(Global Production Net-work,GPN)研究非常深刻地展现了 Peter Dicken所描绘的"全球-地方矛盾".这个概念由Dicken在1994年发表于《Economic Geography》上的Roepke Lecture特邀文章中首次提出[1].作为过去20多年经济地理学的一个主要学术支柱,GPN研究经历了两个重要的理论发展阶段,即从早期的广泛而一般的GPN框架2-4]过渡到更加具备解释性的GPN 2.0理论[5-7].在GPN研究理论快速发展的这个时期里,Coe等首先提出了"战略耦合"这一关键而新颖的概念[4],并由Yeung对其进行了完善[8-10].  相似文献   

Modeling the environmental susceptibility of landfill sites in California     

Victor Fernandez Nascimento  Nazli Yesiller  Keith C Clarke  Jean Pierre Henry Balbaud Ometto  Pedro R. Andrade  Anahi Chimini Sobral 《地理信息系统科学与遥感》2017,54(5):657-677

??The proper management of solid waste (SW) is a global environmental challenge. A major issue is the proper disposal of SW while balancing a wide range of criteria and working with different spatial data. In this study, we used geographic information system as a tool to perform multi-criteria decision analysis with an analytical hierarchy process to develop an environmental impact susceptibility model (EISM) for landfills. The model was applied to the state of California, USA and results are presented herein. In particular, the EISM considers factors such as geology, pedology, geomorphology, water resources, and climate as represented by 13 associated environmental indicators. The results of the EISM indicate that more than 75% of California’s territory is situated in areas with very low, low, and medium environmental impact susceptibility categories. However, in the remaining 25% of the state’s land, 61 landfills are located in the high and very high categories. These results are alarming because during the period from 2000 to 2015, these 61 landfills received approximately 308 million tons of SW, which corresponds to more than 57% of all SW disposed in California. The model results can be used toward mitigating the environmental impacts of these facilities.  相似文献   

Excursion to Mid-lincolnshire,Easter, 1905: From April 20th to 26th, 1905     

Henry Preston 《Proceedings of the Geologists' Association. Geologists' Association》1905,19(3):114-IN4

  相似文献   

The Foraminifera of the Thanet beds of pegwell bay: With Notes on other Microscopic Organisms; A Description of the Section at Pegwell Bay; and Remarks on the Correlation of the Thanet Beds     

Henry W. Burrows  Richard Holland 《Proceedings of the Geologists' Association. Geologists' Association》1897,15(1):19-32

  相似文献   

Visit to the Doulton Potteries,at Lambeth: Wednesday,March 30th, 1887     

Henry Doulton 《Proceedings of the Geologists' Association. Geologists' Association》1887,10(4):130-132

  相似文献   

Ordinary meeting: Friday,January 2nd, 1885     

Henry Hicks 《Proceedings of the Geologists' Association. Geologists' Association》1885,9(2):43-65

  相似文献   

Ordinary meeting: Friday,november 7th, 1884     

Henry Hicks 《Proceedings of the Geologists' Association. Geologists' Association》1885,9(1):1-20

  相似文献