Mostrar mensagens com a etiqueta Xistos de Burgess. Mostrar todas as mensagens
Mostrar mensagens com a etiqueta Xistos de Burgess. Mostrar todas as mensagens

sexta-feira, agosto 30, 2024

Os Xistos de Burgess foram descobertos há 115 anos...!


O Folhelho Burgess ou Xistos de Burgess é um sítio fossilífero das Rochosas, localizado em Colúmbia Britânica, Canadá, e é considerado uma das principais jazidas de fósseis do mundo. Contém grande número de fósseis do Câmbrico médio, extraordinariamente bem preservados, incluindo vários tipos de invertebrados e também os animais dos quais evoluíram os cordados, como o Pikaia, advindo daí a sua extrema importância na paleontologia.
Xistos de Burgess foi o termo informal que Charles Walcott usou para se referir a unidade fossilífera, que mais tarde passou a ser aplicada mais amplamente para descrever o tipo de agrupamento de fósseis que é encontrado na pedreira de Walcott. O sítio fossilífero pertence a formação Stephen, que possui uma parte "fina" e outra "espessa", alguns pesquisadores consideram que a parte "fina" deva ser separada como a formação dos Xistos de Burgess.

 

Ottoia, a soft-bodied worm, abundant in the Burgess Shale

The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At 508 million years old (middle Cambrian), it is one of the earliest fossil beds containing soft-part imprints.
The rock unit is a black shale and crops out at a number of localities near the town of Field in Yoho National Park and the Kicking Horse Pass. Another outcrop is in Kootenay National Park 42 km to the south.
   
The first complete Anomalocaris fossil found

  

History and significance
The Burgess Shale was discovered by palaeontologist Charles Walcott on 30 August 1909, towards the end of the season's fieldwork. He returned in 1910 with his sons, daughter, and wife, establishing a quarry on the flanks of Fossil Ridge. The significance of soft-bodied preservation, and the range of organisms he recognised as new to science, led him to return to the quarry almost every year until 1924. At that point, aged 74, he had amassed over 65,000 specimens. Describing the fossils was a vast task, pursued by Walcott until his death in 1927. Walcott, led by scientific opinion at the time, attempted to categorise all fossils into living taxa, and as a result, the fossils were regarded as little more than curiosities at the time. It was not until 1962 that a first-hand reinvestigation of the fossils was attempted, by Alberto Simonetta. This led scientists to recognise that Walcott had barely scratched the surface of information available in the Burgess Shale, and also made it clear that the organisms did not fit comfortably into modern groups.
Excavations were resumed at the Walcott Quarry by the Geological Survey of Canada under the persuasion of trilobite expert Harry Blackmore Whittington, and a new quarry, the Raymond, was established about 20 metres higher up Fossil Ridge. Whittington, with the help of research students Derek Briggs and Simon Conway Morris of the University of Cambridge, began a thorough reassessment of the Burgess Shale, and revealed that the fauna represented were much more diverse and unusual than Walcott had recognized. Indeed, many of the animals present had bizarre anatomical features and only the slightest resemblance to other known animals. Examples include Opabinia, with five eyes and a snout like a vacuum cleaner hose and Hallucigenia, which was originally reconstructed upside down, walking on bilaterally symmetrical spines.

With Parks Canada and UNESCO recognising the significance of the Burgess Shale, collecting fossils became politically more difficult from the mid-1970s. Collections continued to be made by the Royal Ontario Museum. The curator of invertebrate palaeontology, Desmond Collins, identified a number of additional outcrops, stratigraphically both higher and lower than the original Walcott quarry. These localities continue to yield new organisms faster than they can be studied.

Stephen Jay Gould's book Wonderful Life, published in 1989, brought the Burgess Shale fossils to the public's attention. Gould suggests that the extraordinary diversity of the fossils indicates that life forms at the time were much more disparate in body form than those that survive today, and that many of the unique lineages were evolutionary experiments that became extinct. Gould's interpretation of the diversity of Cambrian fauna relied heavily on Simon Conway Morris's reinterpretation of Charles Walcott's original publications. However, Conway Morris strongly disagreed with Gould's conclusions, arguing that almost all the Cambrian fauna could be classified into modern day phyla.
The Burgess Shale has attracted the interest of paleoclimatologists who want to study and predict long-term future changes in Earth's climate. According to Peter Ward and Donald Brownlee in the 2003 book The Life and Death of Planet Earth, climatologists study the fossil records in the Burgess Shale to understand the climate of the Cambrian explosion, and use it to predict what Earth's climate would look like 500 million years in the future when a warming and expanding Sun combined with declining CO2 and oxygen levels eventually heat the Earth toward temperatures not seen since the Archean Eon 3 billion years ago, before the first plants and animals appeared, and therefore understand how and when the last living things will die out.
After the Burgess Shale site was registered as a World Heritage Site in 1980, it was included in the Canadian Rocky Mountain Parks WHS designation in 1984.
In February 2014, the discovery was announced of another Burgess Shale outcrop in Kootenay National Park to the south. In just 15 days of field collecting in 2013, 50 animal species were unearthed at the new site. 

  

quinta-feira, junho 20, 2024

O paleontólogo Harry B. Whittington morreu há catorze anos...

(imagem daqui)
       
Harry Blackmore Whittington (24 de março de 1916 - 20 de junho de 2010) foi um paleontólogo britânico, professor no Departamento de Ciências da Terra, Cambridge, membro do Colégio Sidney Sussex. Estudou na Handsworth Grammar School, em Birmingham, fazendo depois uma licenciatura e doutoramento, em Geologia, na Universidade de Cambridge, onde foi professor de 1966 a 1983 (continuando a publicar, mesmo depois de reformado). Durante a sua carreira paleontológica, que abrange mais de sessenta anos, o Dr. Whittington conseguiu brilhantes resultados no estudo de fósseis de artrópodes do inicio da Era Paleozoica, com um foco particular nas trilobites. Entre as principais realizações do Dr. Whittington estão:
Entre os seus muitos prémios, são de salientar o International Prize for Biology  e a Medalha Wollaston, ambos ganhos em 2001.
    
 
Opabinia - género estudado por Whittington

 Anomalocaris canadensis - espécie estudada por Whittington
          

domingo, março 31, 2024

Charles Doolittle Walcott, paleontólogo que descobriu os Xistos de Burgess, nasceu há 174 anos

       
Charles Doolittle Walcott (New York Mills, Condado de Oneida, Nova Iorque, 31 de março de 1850 - Washington, DC, 9 de fevereiro de 1927) foi um paleontólogo dos Estados Unidos, especialista em invertebrados.
É sobretudo conhecido pela descoberta dos Xistos de Burgess, uma formação geológica na Colúmbia Britânica, Canadá, considerada uma das principais jazidas de fósseis do mundo, que contém grande número de fósseis do período Câmbrico médio extraordinariamente bem preservados, incluindo vários tipos de invertebrados e também os animais dos quais evoluíram os cordados, como o Pikaia, advindo daí a sua extrema importância na paleontologia.
Foi laureado com a medalha Wollaston pela Sociedade Geológica de Londres, em 1918.
     
Opabinia, um dos estranhos animais encontrados nos Xistos de Burgess
  
in Wikipédia

Walcott Quarry
     
Os Xistos de Burgess são uma formação geológica na Colúmbia Britânica, Canadá, considerada uma das principais jazidas de fósseis do mundo. Contém grande número de fósseis do período Câmbrico médio extraordinariamente preservados, incluindo vários tipos de invertebrados e também os animais dos quais evoluíram os cordados, como o Pikaia, advindo daí a sua extrema importância na paleontologia.
 

domingo, março 24, 2024

O paleontólogo Harry Whittington nasceu há 108 anos...

(imagem daqui)

      
Harry Blackmore Whittington (Birmingham, 24 de março de 1916 - Cambridge, 20 de junho de 2010) foi um paleontólogo britânico.
Professor no Departamento de Ciências da Terra, Cambridge, membro do Colégio Sidney Sussex. Frequentou a Escola Handsworth Grammar em Birmingham, seguido por sua licenciatura e doutoramento em Geologia na Universidade de Cambridge, onde foi professor de 1966 a 1983 (continuando a publicar mesmo depois de reformado). Durante a sua carreira paleontológica, que abrange mais de sessenta anos, o Dr. Whittington conseguiu brilhantes resultados no estudo de fósseis de artrópodes do início da Era Paleozóica, com foco particular nas trilobites. Entre as suas principais realizações estão:
Entre os seus muitos prémios, recebeu o International Prize for Biology de 2001 e a Medalha Wollaston, também em 2001.
 
 Anomalocaris canadensis - espécie estudada por Whittington
 
   
Opabinia - género estudado por Whittington
       

quarta-feira, agosto 30, 2023

Os Xistos de Burgess foram descobertos há 114 anos...!


O Folhelho Burgess ou Xistos de Burgess é um sítio fossilífero das Rochosas localizado em Colúmbia Britânica, Canadá, e é considerado uma das principais jazidas de fósseis do mundo. Contém grande número de fósseis do Câmbrico médio extraordinariamente bem preservados, incluindo vários tipos de invertebrados e também os animais dos quais evoluíram os cordados, como o Pikaia, advindo daí a sua extrema importância na paleontologia.
Xistos de Burgess foi o termo informal que Charles Walcott usou para se referir a unidade fossilífera, que mais tarde passou a ser aplicada mais amplamente para descrever o tipo de agrupamento de fósseis que é encontrado na pedreira de Walcott. O sítio fossilífero pertence a formação Stephen, que possui uma parte "fina" e outra "espessa", alguns pesquisadores consideram que a parte "fina" deva ser separada como a formação dos Xistos de Burgess.

 

Ottoia, a soft-bodied worm, abundant in the Burgess Shale

The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At 508 million years old (middle Cambrian), it is one of the earliest fossil beds containing soft-part imprints.
The rock unit is a black shale and crops out at a number of localities near the town of Field in Yoho National Park and the Kicking Horse Pass. Another outcrop is in Kootenay National Park 42 km to the south.
   
The first complete Anomalocaris fossil found

  

History and significance
The Burgess Shale was discovered by palaeontologist Charles Walcott on 30 August 1909, towards the end of the season's fieldwork. He returned in 1910 with his sons, daughter, and wife, establishing a quarry on the flanks of Fossil Ridge. The significance of soft-bodied preservation, and the range of organisms he recognised as new to science, led him to return to the quarry almost every year until 1924. At that point, aged 74, he had amassed over 65,000 specimens. Describing the fossils was a vast task, pursued by Walcott until his death in 1927. Walcott, led by scientific opinion at the time, attempted to categorise all fossils into living taxa, and as a result, the fossils were regarded as little more than curiosities at the time. It was not until 1962 that a first-hand reinvestigation of the fossils was attempted, by Alberto Simonetta. This led scientists to recognise that Walcott had barely scratched the surface of information available in the Burgess Shale, and also made it clear that the organisms did not fit comfortably into modern groups.
Excavations were resumed at the Walcott Quarry by the Geological Survey of Canada under the persuasion of trilobite expert Harry Blackmore Whittington, and a new quarry, the Raymond, was established about 20 metres higher up Fossil Ridge. Whittington, with the help of research students Derek Briggs and Simon Conway Morris of the University of Cambridge, began a thorough reassessment of the Burgess Shale, and revealed that the fauna represented were much more diverse and unusual than Walcott had recognized. Indeed, many of the animals present had bizarre anatomical features and only the slightest resemblance to other known animals. Examples include Opabinia, with five eyes and a snout like a vacuum cleaner hose and Hallucigenia, which was originally reconstructed upside down, walking on bilaterally symmetrical spines.

With Parks Canada and UNESCO recognising the significance of the Burgess Shale, collecting fossils became politically more difficult from the mid-1970s. Collections continued to be made by the Royal Ontario Museum. The curator of invertebrate palaeontology, Desmond Collins, identified a number of additional outcrops, stratigraphically both higher and lower than the original Walcott quarry. These localities continue to yield new organisms faster than they can be studied.

Stephen Jay Gould's book Wonderful Life, published in 1989, brought the Burgess Shale fossils to the public's attention. Gould suggests that the extraordinary diversity of the fossils indicates that life forms at the time were much more disparate in body form than those that survive today, and that many of the unique lineages were evolutionary experiments that became extinct. Gould's interpretation of the diversity of Cambrian fauna relied heavily on Simon Conway Morris's reinterpretation of Charles Walcott's original publications. However, Conway Morris strongly disagreed with Gould's conclusions, arguing that almost all the Cambrian fauna could be classified into modern day phyla.
The Burgess Shale has attracted the interest of paleoclimatologists who want to study and predict long-term future changes in Earth's climate. According to Peter Ward and Donald Brownlee in the 2003 book The Life and Death of Planet Earth, climatologists study the fossil records in the Burgess Shale to understand the climate of the Cambrian explosion, and use it to predict what Earth's climate would look like 500 million years in the future when a warming and expanding Sun combined with declining CO2 and oxygen levels eventually heat the Earth toward temperatures not seen since the Archean Eon 3 billion years ago, before the first plants and animals appeared, and therefore understand how and when the last living things will die out.
After the Burgess Shale site was registered as a World Heritage Site in 1980, it was included in the Canadian Rocky Mountain Parks WHS designation in 1984.
In February 2014, the discovery was announced of another Burgess Shale outcrop in Kootenay National Park to the south. In just 15 days of field collecting in 2013, 50 animal species were unearthed at the new site. 

  

terça-feira, junho 20, 2023

O paleontólogo Harry B. Whittington morreu há treze anos...

(imagem daqui)
       
Harry Blackmore Whittington (24 de março de 1916 - 20 de junho de 2010) foi um paleontólogo britânico, professor no Departamento de Ciências da Terra, Cambridge, membro do Colégio Sidney Sussex. Estudou na Handsworth Grammar School, em Birmingham, fazendo depois uma licenciatura e doutoramento, em Geologia, na Universidade de Cambridge, onde foi professor de 1966 a 1983 (continuando a publicar, mesmo depois de reformado). Durante a sua carreira paleontológica, que abrange mais de sessenta anos, o Dr. Whittington conseguiu brilhantes resultados no estudo de fósseis de artrópodes do inicio da Era Paleozoica, com um foco particular nas trilobites. Entre as principais realizações do Dr. Whittington estão:
Entre os seus muitos prémios, são de salientar o International Prize for Biology  e a Medalha Wollaston, ambos ganhos em 2001.
    
 
Opabinia - género estudado por Whittington

 Anomalocaris canadensis - espécie estudada por Whittington
          

sexta-feira, março 31, 2023

Charles Doolittle Walcott, o paleontólogo que descobriu os Xistos de Burgess, nasceu há 173 anos

       
Charles Doolittle Walcott (New York Mills, Condado de Oneida, Nova Iorque, 31 de março de 1850 - Washington, DC, 9 de fevereiro de 1927) foi um paleontólogo dos Estados Unidos, especialista em invertebrados.
É sobretudo conhecido pela descoberta dos Xistos de Burgess, uma formação geológica na Colúmbia Britânica, Canadá, considerada uma das principais jazidas de fósseis do mundo, que contém grande número de fósseis do período Câmbrico médio extraordinariamente preservados, incluindo vários tipos de invertebrados e também os animais dos quais evoluíram os cordados, como o Pikaia, advindo daí a sua extrema importância na paleontologia.
Foi laureado com a medalha Wollaston pela Sociedade Geológica de Londres, em 1918.
     
Opabinia, um dos estranhos animais encontrados nos Xistos de Burgess
  
in Wikipédia

Walcott Quarry
     
Os Xistos de Burgess são uma formação geológica na Colúmbia Britânica, Canadá, considerada uma das principais jazidas de fósseis do mundo. Contém grande número de fósseis do período Câmbrico médio extraordinariamente preservados, incluindo vários tipos de invertebrados e também os animais dos quais evoluíram os cordados, como o Pikaia, advindo daí a sua extrema importância na paleontologia.
 

sexta-feira, março 24, 2023

O paleontólogo Harry Whittington nasceu há 107 anos

(imagem daqui)

      
Harry Blackmore Whittington (Birmingham, 24 de março de 1916 - Cambridge, 20 de junho de 2010) foi um paleontólogo britânico.
Professor no Departamento de Ciências da Terra, Cambridge, membro do Colégio Sidney Sussex. Frequentou a Escola Handsworth Grammar em Birmingham, seguido por sua licenciatura e doutoramento em Geologia na Universidade de Cambridge, onde foi professor de 1966 a 1983 (continuando a publicar mesmo depois de reformado). Durante a sua carreira paleontológica, que abrange mais de sessenta anos, o Dr. Whittington conseguiu brilhantes resultados no estudo de fósseis de artrópodes do início da Era Paleozóica, com foco particular nas trilobites. Entre as suas principais realizações estão:
Entre os seus muitos prémios, recebeu o International Prize for Biology de 2001 e a Medalha Wollaston, também em 2001.
   
Opabinia - género estudado por Whittington
       

terça-feira, agosto 30, 2022

Os Xistos de Burgess foram descobertos há 113 anos...!


O Folhelho Burgess ou Xistos de Burgess é um sítio fossilífero das Rochosas localizado em Colúmbia Britânica, Canadá, e é considerado uma das principais jazidas de fósseis do mundo. Contém grande número de fósseis do período Câmbrico médio extraordinariamente bem preservados, incluindo vários tipos de invertebrados e também os animais dos quais evoluíram os cordados, como o Pikaia, advindo daí a sua extrema importância na paleontologia.
Xistos de Burgess foi o termo informal que Charles Walcott usou para se referir a unidade fossilífera, que mais tarde passou a ser aplicada mais amplamente para descrever o tipo de agrupamento de fósseis que é encontrado na pedreira de Walcott. O sítio fossilífero pertence a formação Stephen, que possui uma parte "fina" e outra "grossa", alguns pesquisadores consideram que a parte "fina" deva ser separada como formação dos Xistos de Burgess.

 

Ottoia, a soft-bodied worm, abundant in the Burgess Shale

The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At 508 million years old (middle Cambrian), it is one of the earliest fossil beds containing soft-part imprints.
The rock unit is a black shale and crops out at a number of localities near the town of Field in Yoho National Park and the Kicking Horse Pass. Another outcrop is in Kootenay National Park 42 km to the south.
   
The first complete Anomalocaris fossil found

  

History and significance
The Burgess Shale was discovered by palaeontologist Charles Walcott on 30 August 1909, towards the end of the season's fieldwork. He returned in 1910 with his sons, daughter, and wife, establishing a quarry on the flanks of Fossil Ridge. The significance of soft-bodied preservation, and the range of organisms he recognised as new to science, led him to return to the quarry almost every year until 1924. At that point, aged 74, he had amassed over 65,000 specimens. Describing the fossils was a vast task, pursued by Walcott until his death in 1927. Walcott, led by scientific opinion at the time, attempted to categorise all fossils into living taxa, and as a result, the fossils were regarded as little more than curiosities at the time. It was not until 1962 that a first-hand reinvestigation of the fossils was attempted, by Alberto Simonetta. This led scientists to recognise that Walcott had barely scratched the surface of information available in the Burgess Shale, and also made it clear that the organisms did not fit comfortably into modern groups.
Excavations were resumed at the Walcott Quarry by the Geological Survey of Canada under the persuasion of trilobite expert Harry Blackmore Whittington, and a new quarry, the Raymond, was established about 20 metres higher up Fossil Ridge. Whittington, with the help of research students Derek Briggs and Simon Conway Morris of the University of Cambridge, began a thorough reassessment of the Burgess Shale, and revealed that the fauna represented were much more diverse and unusual than Walcott had recognized. Indeed, many of the animals present had bizarre anatomical features and only the slightest resemblance to other known animals. Examples include Opabinia, with five eyes and a snout like a vacuum cleaner hose and Hallucigenia, which was originally reconstructed upside down, walking on bilaterally symmetrical spines.

With Parks Canada and UNESCO recognising the significance of the Burgess Shale, collecting fossils became politically more difficult from the mid-1970s. Collections continued to be made by the Royal Ontario Museum. The curator of invertebrate palaeontology, Desmond Collins, identified a number of additional outcrops, stratigraphically both higher and lower than the original Walcott quarry. These localities continue to yield new organisms faster than they can be studied.

Stephen Jay Gould's book Wonderful Life, published in 1989, brought the Burgess Shale fossils to the public's attention. Gould suggests that the extraordinary diversity of the fossils indicates that life forms at the time were much more disparate in body form than those that survive today, and that many of the unique lineages were evolutionary experiments that became extinct. Gould's interpretation of the diversity of Cambrian fauna relied heavily on Simon Conway Morris's reinterpretation of Charles Walcott's original publications. However, Conway Morris strongly disagreed with Gould's conclusions, arguing that almost all the Cambrian fauna could be classified into modern day phyla.
The Burgess Shale has attracted the interest of paleoclimatologists who want to study and predict long-term future changes in Earth's climate. According to Peter Ward and Donald Brownlee in the 2003 book The Life and Death of Planet Earth, climatologists study the fossil records in the Burgess Shale to understand the climate of the Cambrian explosion, and use it to predict what Earth's climate would look like 500 million years in the future when a warming and expanding Sun combined with declining CO2 and oxygen levels eventually heat the Earth toward temperatures not seen since the Archean Eon 3 billion years ago, before the first plants and animals appeared, and therefore understand how and when the last living things will die out. See also Future of the Earth.
After the Burgess Shale site was registered as a World Heritage Site in 1980, it was included in the Canadian Rocky Mountain Parks WHS designation in 1984.
In February 2014, the discovery was announced of another Burgess Shale outcrop in Kootenay National Park to the south. In just 15 days of field collecting in 2013, 50 animal species were unearthed at the new site. 

  

segunda-feira, junho 20, 2022

O paleontólogo Harry B. Whittington morreu há doze anos

(imagem daqui)
       
Harry Blackmore Whittington (24 de março de 1916 - 20 de junho de 2010) foi um paleontólogo britânico, professor no Departamento de Ciências da Terra, Cambridge, membro do Colégio Sidney Sussex. Estudou na Handsworth Grammar School, em Birmingham, fazendo depois uma licenciatura e doutoramento, em Geologia, na Universidade de Cambridge, onde foi professor de 1966 a 1983 (continuando a publicar, mesmo depois de reformado). Durante a sua carreira paleontológica, que abrange mais de sessenta anos, o Dr. Whittington conseguiu brilhantes resultados no estudo de fósseis de artrópodes do inicio da Era Paleozoica, com um foco particular em trilobites. Entre as principais realizações do Dr. Whittington estão:
Entre os seus muitos prémios, são de salientar o International Prize for Biology  e a Medalha Wollaston, ambos ganhos em 2001.
    
 
Opabinia - género estudado por Whittington

 Anomalocaris canadensis - espécie estudada por Whittington
          

quinta-feira, março 31, 2022

Charles Doolittle Walcott, o paleontólogo que descobriu os Xistos de Burgess, nasceu há 172 anos

       
Charles Doolittle Walcott (New York Mills, Condado de Oneida, Nova Iorque, 31 de março de 1850 - Washington, DC, 9 de fevereiro de 1927) foi um paleontólogo dos Estados Unidos, especialista em invertebrados.
É sobretudo conhecido pela descoberta dos Xistos de Burgess, uma formação geológica na Colúmbia Britânica, Canadá, considerada uma das principais jazidas de fósseis do mundo, que contém grande número de fósseis do período Câmbrico médio extraordinariamente preservados, incluindo vários tipos de invertebrados e também os animais dos quais evoluíram os cordados, como o Pikaia, advindo daí a sua extrema importância na paleontologia.
Foi laureado com a medalha Wollaston pela Sociedade Geológica de Londres, em 1918.
     
Opabinia, um dos estranhos animais encontrados nos Xistos de Burgess
  
in Wikipédia

Walcott Quarry
     
Os Xistos de Burgess são uma formação geológica na Colúmbia Britânica, Canadá, considerada uma das principais jazidas de fósseis do mundo. Contém grande número de fósseis do período Câmbrico médio extraordinariamente preservados, incluindo vários tipos de invertebrados e também os animais dos quais evoluíram os cordados, como o Pikaia, advindo daí a sua extrema importância na paleontologia.
 

quinta-feira, março 24, 2022

O paleontólogo Harry Whittington nasceu há 106 anos


(imagem daqui)
      
Harry Blackmore Whittington (Birmingham, 24 de março de 1916 - Cambridge, 20 de junho de 2010) foi um paleontólogo britânico.
Professor no Departamento de Ciências da Terra, Cambridge, membro do Colégio Sidney Sussex. Frequentou a Escola Handsworth Grammar em Birmingham, seguido por sua licenciatura e doutoramento em Geologia na Universidade de Cambridge, onde foi professor de 1966 a 1983 (continuando a publicar mesmo depois de reformado). Durante a sua carreira paleontológica, que abrange mais de sessenta anos, o Dr. Whittington conseguiu brilhantes resultados no estudo de fósseis de artrópodes do início da Era Paleozóica, com foco particular nas trilobites. Entre as suas principais realizações estão:
Entre os seus muitos prémios, recebeu o International Prize for Biology de 2001 e a Medalha Wollaston, também em 2001.
   
Opabinia - género estudado por Whittington
       

segunda-feira, agosto 30, 2021

Os Xistos de Burgess foram descobertos há 112 anos...!


O Folhelho Burgess ou Xistos de Burgess é um sítio fossilífero das Rochosas localizado em Colúmbia Britânica, Canadá, e é considerado uma das principais jazidas de fósseis do mundo. Contém grande número de fósseis do período Câmbrico médio extraordinariamente bem preservados, incluindo vários tipos de invertebrados e também os animais dos quais evoluíram os cordados, como o Pikaia, advindo daí a sua extrema importância na paleontologia.
Xistos de Burgess foi o termo informal que Charles Walcott usou para se referir a unidade fossilífera, que mais tarde passou a ser aplicada mais amplamente para descrever o tipo de agrupamento de fósseis que é encontrado na pedreira de Walcott. O sítio fossilífero pertence a formação Stephen, que possui uma parte "fina" e outra "grossa", alguns pesquisadores consideram que a parte "fina" deva ser separada como formação dos Xistos de Burgess.

 

Ottoia, a soft-bodied worm, abundant in the Burgess Shale. (From Smith et al. 2015)

The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At 508 million years old (middle Cambrian), it is one of the earliest fossil beds containing soft-part imprints.
The rock unit is a black shale and crops out at a number of localities near the town of Field in Yoho National Park and the Kicking Horse Pass. Another outcrop is in Kootenay National Park 42 km to the south.
   
The first complete Anomalocaris fossil found

  

History and significance
The Burgess Shale was discovered by palaeontologist Charles Walcott on 30 August 1909, towards the end of the season's fieldwork. He returned in 1910 with his sons, daughter, and wife, establishing a quarry on the flanks of Fossil Ridge. The significance of soft-bodied preservation, and the range of organisms he recognised as new to science, led him to return to the quarry almost every year until 1924. At that point, aged 74, he had amassed over 65,000 specimens. Describing the fossils was a vast task, pursued by Walcott until his death in 1927. Walcott, led by scientific opinion at the time, attempted to categorise all fossils into living taxa, and as a result, the fossils were regarded as little more than curiosities at the time. It was not until 1962 that a first-hand reinvestigation of the fossils was attempted, by Alberto Simonetta. This led scientists to recognise that Walcott had barely scratched the surface of information available in the Burgess Shale, and also made it clear that the organisms did not fit comfortably into modern groups.
Excavations were resumed at the Walcott Quarry by the Geological Survey of Canada under the persuasion of trilobite expert Harry Blackmore Whittington, and a new quarry, the Raymond, was established about 20 metres higher up Fossil Ridge. Whittington, with the help of research students Derek Briggs and Simon Conway Morris of the University of Cambridge, began a thorough reassessment of the Burgess Shale, and revealed that the fauna represented were much more diverse and unusual than Walcott had recognized. Indeed, many of the animals present had bizarre anatomical features and only the slightest resemblance to other known animals. Examples include Opabinia, with five eyes and a snout like a vacuum cleaner hose and Hallucigenia, which was originally reconstructed upside down, walking on bilaterally symmetrical spines.

With Parks Canada and UNESCO recognising the significance of the Burgess Shale, collecting fossils became politically more difficult from the mid-1970s. Collections continued to be made by the Royal Ontario Museum. The curator of invertebrate palaeontology, Desmond Collins, identified a number of additional outcrops, stratigraphically both higher and lower than the original Walcott quarry. These localities continue to yield new organisms faster than they can be studied.

Stephen Jay Gould's book Wonderful Life, published in 1989, brought the Burgess Shale fossils to the public's attention. Gould suggests that the extraordinary diversity of the fossils indicates that life forms at the time were much more disparate in body form than those that survive today, and that many of the unique lineages were evolutionary experiments that became extinct. Gould's interpretation of the diversity of Cambrian fauna relied heavily on Simon Conway Morris's reinterpretation of Charles Walcott's original publications. However, Conway Morris strongly disagreed with Gould's conclusions, arguing that almost all the Cambrian fauna could be classified into modern day phyla.
The Burgess Shale has attracted the interest of paleoclimatologists who want to study and predict long-term future changes in Earth's climate. According to Peter Ward and Donald Brownlee in the 2003 book The Life and Death of Planet Earth, climatologists study the fossil records in the Burgess Shale to understand the climate of the Cambrian explosion, and use it to predict what Earth's climate would look like 500 million years in the future when a warming and expanding Sun combined with declining CO2 and oxygen levels eventually heat the Earth toward temperatures not seen since the Archean Eon 3 billion years ago, before the first plants and animals appeared, and therefore understand how and when the last living things will die out. See also Future of the Earth.
After the Burgess Shale site was registered as a World Heritage Site in 1980, it was included in the Canadian Rocky Mountain Parks WHS designation in 1984.
In February 2014, the discovery was announced of another Burgess Shale outcrop in Kootenay National Park to the south. In just 15 days of field collecting in 2013, 50 animal species were unearthed at the new site.