Louisiana Geological Survey 208 Howe-Russell Geoscience Complex Baton Rouge, Louisiana 70803 Tel: 225 578 5320 Fax: 225 578 3662 1934 Fossils, the preserved remains or evidence of past life, are the only direct means of documenting the history of life on the Earth. Fossils range in size from the microscopic shells of amoeba-like organisms known as foraminifera to the bones of 30 meter-long dinosaurs. The most common fossils are marine organisms, those that lived in the oceans, because oceans cover over 70% of the earth and provide a more suitable environment for fossil preservation than most environments on land. Specialists known as paleontologists study these glimpses into the past in order to unravel this planet’s long and intriguing development of animals, protists (simple one-celled organisms), and plants (Pojeta and Springer, 2001). Exposed strata or sediments where fossils may be recovered are known as fossiliferous outcrops. Such outcrops are rare in Louisiana for a variety of reasons. Outcrops exposed by road construction or by natural means will often be covered quickly by the state’s abundant vegetation. Furthermore, in a geological context, the surface exposures of Louisiana are very young in age, and this affects the number and diversity of fossils. Examination of the Geologic Map of Louisiana (Snead and McCulloh, 1984) reveals that the oldest surface sediments are Cretaceous in age (approximately 70 million years old). These sediments are rare and occur only around salt domes where the strata have been pushed to the surface. The vast majority of surface exposures in Louisiana are Tertiary and Quaternary in age (less than 65 million years old); many of the sediments are even younger (less than 10,000 years old). This is in contrast to some states that have surface exposures that span hundreds of millions of years. This immense amount of time increases the probability of finding extinct organisms as well as a greater diversity of fossils. Also, large portions of the surface sediments in Louisiana were formed as parts of rivers, ancient deltas, and swamps. These terrestrial and transitional environments, which were common in the geologic past in Louisiana, are not nearly as conducive for the preservation of fossils as the marine environment. Therefore, these factors cause marine fossils to be relatively uncommon in the surface exposures in Louisiana. 46-MILLION-YEAR-OLD MARINE
电话:225 578 5320传真:225 578 3662 1934化石，保存下来的遗骸或过去生命的证据，是记录地球上生命历史的唯一直接手段。化石的大小不等，从被称为有孔虫的类似变形虫的生物的微观外壳到30米长的恐龙的骨头。最常见的化石是海洋生物，那些生活在海洋中的生物，因为海洋覆盖了地球的70%以上，比大多数陆地环境提供了更适合化石保存的环境。被称为古生物学家的专家研究这些对过去的一瞥，以揭示这个星球上动物、原生生物(简单的单细胞生物)和植物的漫长而有趣的发展(Pojeta和施普林格，2001)。可能发现化石的裸露地层或沉积物被称为化石露头。由于种种原因，这种露头在路易斯安那州很少见。道路建设或自然方式暴露出来的露头通常会很快被该州丰富的植被覆盖。此外，在地质环境中，路易斯安那州地表暴露的年代非常年轻，这影响了化石的数量和多样性。对路易斯安那州地质图(Snead and McCulloh, 1984)的检查显示，最古老的地表沉积物年龄为白垩纪(约7000万年)。这些沉积物很罕见，只出现在地层被推到地表的盐丘周围。路易斯安那州地表暴露的绝大多数是第三纪和第四纪(年龄小于6500万年);许多沉积物甚至更年轻(不到一万年)。这与一些表面暴露时间长达数亿年的州形成了鲜明对比。这大量的时间增加了发现灭绝生物的可能性，也增加了化石的多样性。此外，路易斯安那州的大部分地表沉积物是作为河流、古三角洲和沼泽的一部分形成的。这些陆地和过渡性的环境，在过去的地质时期在路易斯安那州很常见，却不像海洋环境那样有利于化石的保存。因此，这些因素导致海洋化石在路易斯安那州的地表暴露中相对不常见
{"title":"Fossils:","authors":"M. Viney, Hermanophyton Taylorii","doi":"10.2307/j.ctvss3zt8.7","DOIUrl":"https://doi.org/10.2307/j.ctvss3zt8.7","url":null,"abstract":"Louisiana Geological Survey 208 Howe-Russell Geoscience Complex Baton Rouge, Louisiana 70803 Tel: 225 578 5320 Fax: 225 578 3662 1934 Fossils, the preserved remains or evidence of past life, are the only direct means of documenting the history of life on the Earth. Fossils range in size from the microscopic shells of amoeba-like organisms known as foraminifera to the bones of 30 meter-long dinosaurs. The most common fossils are marine organisms, those that lived in the oceans, because oceans cover over 70% of the earth and provide a more suitable environment for fossil preservation than most environments on land. Specialists known as paleontologists study these glimpses into the past in order to unravel this planet’s long and intriguing development of animals, protists (simple one-celled organisms), and plants (Pojeta and Springer, 2001). Exposed strata or sediments where fossils may be recovered are known as fossiliferous outcrops. Such outcrops are rare in Louisiana for a variety of reasons. Outcrops exposed by road construction or by natural means will often be covered quickly by the state’s abundant vegetation. Furthermore, in a geological context, the surface exposures of Louisiana are very young in age, and this affects the number and diversity of fossils. Examination of the Geologic Map of Louisiana (Snead and McCulloh, 1984) reveals that the oldest surface sediments are Cretaceous in age (approximately 70 million years old). These sediments are rare and occur only around salt domes where the strata have been pushed to the surface. The vast majority of surface exposures in Louisiana are Tertiary and Quaternary in age (less than 65 million years old); many of the sediments are even younger (less than 10,000 years old). This is in contrast to some states that have surface exposures that span hundreds of millions of years. This immense amount of time increases the probability of finding extinct organisms as well as a greater diversity of fossils. Also, large portions of the surface sediments in Louisiana were formed as parts of rivers, ancient deltas, and swamps. These terrestrial and transitional environments, which were common in the geologic past in Louisiana, are not nearly as conducive for the preservation of fossils as the marine environment. Therefore, these factors cause marine fossils to be relatively uncommon in the surface exposures in Louisiana. 46-MILLION-YEAR-OLD MARINE","PeriodicalId":211035,"journal":{"name":"Cosmology’s Century","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120919560","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}
Pub Date : 2019-12-31DOI: 10.1515/9780691184975-011
M. Conway
{"title":"A NOTE ON THE TYPE","authors":"M. Conway","doi":"10.1515/9780691184975-011","DOIUrl":"https://doi.org/10.1515/9780691184975-011","url":null,"abstract":"","PeriodicalId":211035,"journal":{"name":"Cosmology’s Century","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130607669","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}
Pub Date : 2012-01-02DOI: 10.1002/9781119206316.PART2
E. D. Haan
{"title":"The Ways of Research","authors":"E. D. Haan","doi":"10.1002/9781119206316.PART2","DOIUrl":"https://doi.org/10.1002/9781119206316.PART2","url":null,"abstract":"","PeriodicalId":211035,"journal":{"name":"Cosmology’s Century","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124975179","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}
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