Geological Society special publication最新文献

Three common sampling techniques in Pleistocene coral reefs of the Red Sea: a comparison. 红海更新世珊瑚礁的三种常见采样技术：比较。

Geological Society special publication Pub Date : 2023-07-03 Epub Date: 2023-04-04 DOI: 10.1144/SP529-2022-227

Angelina Ivkić, Felix Puff, Andreas Kroh, Abbas Mansour, Mohamed Osman, Mohamed Hassan, Abo El Hagag Ahmed, Martin Zuschin

{"title":"Three common sampling techniques in Pleistocene coral reefs of the Red Sea: a comparison.","authors":"Angelina Ivkić, Felix Puff, Andreas Kroh, Abbas Mansour, Mohamed Osman, Mohamed Hassan, Abo El Hagag Ahmed, Martin Zuschin","doi":"10.1144/SP529-2022-227","DOIUrl":"10.1144/SP529-2022-227","url":null,"abstract":"Line Intercept Transects (LIT), Point Intercept Transects (PIT), and Photoquadrats (PQ) are the most common quantitative sampling techniques in modern and fossil coral reefs. Data from coral reefs obtained by the different methods are generally compared between various reef ages and localities. Quaternary reefs from warmer interglacial periods, which represent climate scenarios projected for the future, are particularly interesting for comparisons with modern reefs. Importantly, fossil reefs differ from modern reefs because they are diagenetically altered and time averaged. While several studies have compared different quantitative methods in modern reefs, very few have dealt with the comparability among fossil and between fossil and modern reefs. Here, we compare LIT, PIT at 10, 20 and 50 cm intervals, and PQ in two Pleistocene reef localities in Egypt. We find that alpha diversity, reef cover and community composition are dependent on the method. Results gained with plotless methods (LIT, PIT) differ strongly from results gained with plot methods (PQ). However, coral cover results are similar between LIT and PIT, and community composition is indistinguishable between the two, but alpha diversity depends on the interval used for PIT. We discuss the implications of our findings for comparing coral reefs of various ages and localities. We recommend surveying Pleistocene reefs with PIT at 20 cm intervals. This is because A) alpha diversity is well captured, B) the amount of time averaging recorded by PIT is reduced compared to PQ, C) the PIT results can be directly compared to reefs analyzed by LIT, and D) the method is less time consuming than LIT and PQ.","PeriodicalId":90505,"journal":{"name":"Geological Society special publication","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7615226/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49694937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dune-slope activity due to frost and wind throughout the north polar erg, Mars. 由于整个火星北极地区的霜冻和风造成的沙丘斜坡活动。

Geological Society special publication Pub Date : 2017-01-01 Epub Date: 2017-11-27 DOI: 10.1144/SP467.6

Serina Diniega, Candice J Hansen, Amanda Allen, Nathan Grigsby, Zheyu Li, Tyler Perez, Matthew Chojnacki

{"title":"Dune-slope activity due to frost and wind throughout the north polar erg, Mars.","authors":"Serina Diniega, Candice J Hansen, Amanda Allen, Nathan Grigsby, Zheyu Li, Tyler Perez, Matthew Chojnacki","doi":"10.1144/SP467.6","DOIUrl":"https://doi.org/10.1144/SP467.6","url":null,"abstract":"Repeat, high-resolution imaging of dunes within the Martian north polar erg have shown that these dune slopes are very active, with alcoves forming along the dune brink each Mars year. In some areas, a few hundred cubic metres of downslope sand movement have been observed, sometimes moving the dune brink 'backwards'. Based on morphological and activity-timing similarities of these north polar features to southern dune gullies, identifying the processes forming these features is likely to have relevance for understanding the general evolution/modification of dune gullies. To determine alcove-formation model constraints, we have surveyed seven dune fields, each over 1-4 Mars winters. Consistent with earlier reports, we found that alcove-formation activity occurs during the autumn-winter seasons, before or while the stable seasonal frost layer is deposited. We propose a new model in which alcove formation occurs during the autumn, and springtime sublimation activity then enhances the feature. Summertime winds blow sand into the new alcoves, erasing small alcoves over a few Mars years. Based on the observed rate of alcove erasure, we estimated the effective aeolian sand transport flux. From this, we proposed that alcove formation may account for 2-20% of the total sand movement within these dune fields.","PeriodicalId":90505,"journal":{"name":"Geological Society special publication","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/SP467.6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36076613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 69

Conservatism of Late Pennsylvanian vegetational patterns during short-term cyclic and long-term directional environmental change, western equatorial Pangea. 赤道盘古大陆西部晚宾夕法尼亚期植被格局在短期循环和长期定向环境变化中的保守性。

Geological Society special publication Pub Date : 2013-09-19 DOI: 10.1144/sp376.14

Neil J Tabor, Charles M Romanchock, Cynthia V Looy, Carol L Hotton, William A Dimichele, Dan S Chaney

{"title":"Conservatism of Late Pennsylvanian vegetational patterns during short-term cyclic and long-term directional environmental change, western equatorial Pangea.","authors":"Neil J Tabor, Charles M Romanchock, Cynthia V Looy, Carol L Hotton, William A Dimichele, Dan S Chaney","doi":"10.1144/sp376.14","DOIUrl":"https://doi.org/10.1144/sp376.14","url":null,"abstract":"Patterns of plant distribution by palaeoenvironment were examined across the Pennsylvanian-Permian transition in North-Central Texas. Stratigraphically recurrent packages of distinct lithofacies, representing different habitats, contain qualitatively and quantitatively different macrofloras and microfloras. The species pools demonstrate niche conservatism, remaining closely tied to specific habitats, during both short-term cyclic environmental change and a long-term trend of increasing aridity. The deposits examined principally comprise the terrestrial Markley and its approximate marine equivalent, the Harpersville Formation and parts of lower Archer City Formation. Fossiliferous deposits are lens-like, likely representing fill sequences of channels formed during abandonment phases. Palaeosols, represented by blocky mudstones, comprise a large fraction of the deposits. They suggest progressive climate change from minimally seasonal humid to seasonal subhumid to seasonal dry subhumid. Five lithofacies yielded plants: kaolinite-dominated siltstone, organic shale, mudstone beds within organic shale, coarsening upward mudstone-sandstone interbeds and channel sandstone. Both macro- and microflora were examined. Lithofacies proved compositionally distinct, with different patterns of dominance diversity. Organic shales (swamp deposits), mudstone partings (swamp drainages) and coarsening upward mudstone-sandstone interbeds (floodplains) typically contain Pennsylvanian wetland vegetation. Kaolinite-dominated siltstones and (to the extent known) sandstones contain taxa indicative of seasonally dry substrates. Some kaolinite-dominated siltstones and organic shales/coals yielded palynomorphs. Microfloras are more diverse, with greater wetland-dryland overlap than macrofloras. It appears that these two floras were coexistent at times on the regional landscape.","PeriodicalId":90505,"journal":{"name":"Geological Society special publication","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1144/sp376.14","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32768138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 27

Bedding structures in Indian tsunami deposits that provide clues to the dynamics of tsunami inundation 印度海啸沉积物中的层理结构为海啸淹没动力学提供了线索

Geological Society special publication Pub Date : 2012-01-01 DOI: 10.1144/SP361.6

A. Switzer, S. Srinivasalu, N. Thangadurai, V. R. Ram Mohan

{"title":"Bedding structures in Indian tsunami deposits that provide clues to the dynamics of tsunami inundation","authors":"A. Switzer, S. Srinivasalu, N. Thangadurai, V. R. Ram Mohan","doi":"10.1144/SP361.6","DOIUrl":"https://doi.org/10.1144/SP361.6","url":null,"abstract":"Abstract The 2004 Indian Ocean tsunami deposited an extensive sandsheet on the coastal plain of SE India. At particular sites, the sedimentary bedding in the sandsheet provides evidence of variable energy conditions and flow during inundation of the coast. Trenching of the deposits at sites where only unidirectional flow was observed allowed the investigation of changes in hydrodynamics recorded in bedding structures without the added complexity of return flows and reworking. A high-velocity initial surge is recorded as upper flow regime (UFR) plane bedding. Following the initial high flow a period of falling flow velocity and quiescence occurs where sediments settle out of suspension, often resulting in a reverse graded bed that transitions to a graded (fining-up) bed. As water levels begin to decline after maximum inundation sheet flow caused the formation of inversely graded (coarsening-up) beds or a return to UFR conditions. At one site the final stages of tsunami inundation is recorded as small channels that have an erosional base and are filled with graded sediments that exhibit complex patterns of sedimentation. Pits excavated in areas of unidirectional flow allow the development of a sedimentary model for tsunami sediment dynamics across flat topography under unidirectional flow conditions.","PeriodicalId":90505,"journal":{"name":"Geological Society special publication","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81810595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 37

The biostratigraphical and palaeogeographical framework of the earliest diversification of tetrapods (Late Devonian) 晚泥盆世四足动物最早多样化的生物地层古地理格架

Geological Society special publication Pub Date : 2007-01-01 DOI: 10.1144/SP278.10

A. Blieck, G. Clément, H. Blom, H. Lelièvre, E. Lukševičs, M. Streel, J. Thorez, Gavin Young

引用次数: 41