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Application of holocene geological data for siting coastal nuclear power plants: An example from Puerto Rico

  • Shlemon R. J. 
  • Capacete J. L. 
Section 13 Engineering Geology

Summary

Geological and geophysical investigations for a nuclear power plant (NORCO) on the north-central coast of Puerto Rico indicate that the proposed site is structurally suitable and free of late Quaternary faults. However, conflicting interpretation of erosional geomorphic features, primarily nips, terraces and caves cut in coastal eolianities and jointed Tertiary carbonates a few to 10 m above sea level, suggest the possibility of non-fault related epeirogeny as young as Holocene in age. Seven peat samples cored from Ciénaga Tiburones, a coastal marsh within the site area, and three wood samples from near-coast fluvial sediments at Arecibo and San Juan, yielded radiocarbon dates ranging in age from about 1,200 to 8,700 years BP. The age and depth associations of these dated sediments fall within or slightly below an envelope defining the maximum oscillatory points of 15 world-wide, Holocene sea level curves. The relationship of the Puerto Rico and world-wide curves suggests no measurable epeirogenic uplift of the north-central coast for at least the last 10,000 years. Coastal caves and terraces above present sea level thus owe their origin to pre-Holocene high stands, or to cave collapse, storm surge, and other modern processes capable of producing erosional features above present tidal range. The analysis of Holocene geological data for north-central Puerto Rico may be a useful technique applicable for siting coastal nuclear power plants elsewhere in the world.

Keywords

Holocene Nuclear Power Plant Coastal Marsh Geological Survey Professional Paper Insular Shelf 

Application Des Données Géologiques De L’holocene Au Choix Du Site De Centrales Nucléaires Cotieres: Un exemple De Porto Rico

Résumé

Les études géologiques et géophysiques effectuées dans le centre de la côte nord de l’íle de Porto-Rico, en vue de la construction d’une centrale nucléaire montrent que le site proposé a une structure convenable et qu’il n’est pas affecté par des failles quaternaires récentes. Cependant, une interprétation discutable de caractères morphologiques dus à l’érosion, principalement des étranglements, des terrasses et des cavernes, découpées dans des formations éoliennes côtières et dans des carbonates tertiaires fissurés, entre quelques mètres et dix mètres au-dessus du niveau de la mer, suggère la possibilité d’une épéirogénie sans faille aussi récente que l’Holocene. Sept échantillons de tourbe, carottés à Ciénaga Tiburones, un marais côtier situé dans le secteur étudié, et trois échantillons de bois provenant de sédiments fluviatiles proches de la côte, à Arecibo et à San Juan, ont donné des ãges au carbone 14 compris entre 1200 et 8700 ans BP environ. Pour ces sédiments datés, les points représentatifs de l’âge en fonction de la profondeur se situent dans une enveloppe définie par les points maximaux des courbes représentant les oscillations du niveau de la mer à l’Holocène en 15 sites répartis dans le monde entier, ou légèrement au-dessous de cette enveloppe. Les relations entre les courbes de Porto Rico et celles d’autres points du monde suggèrent qu’il n’y a pas eu de soulèvement épéirogénique mesurable dans le centre de la côte nord depuis au moins 10 000 ans. Aussi les cavernes et terrasses côtières au-dessus du niveau actuel de la mer doivent elles s’expliquer par des niveaux élevés atteints par la mer avant l’Holocène ou par des effondrements de cavernes, des vagues de tempête ou d’autres phénomènes récents pouvant produire des figures d’érosion au-dessus du niveau actuel des marées. L’analyse des données géologiques concernant l’Holocène du centre de la côte nord de Porto Rico peut constituer une méthode pratique applicable au choix du site d’une centrale nucléaire côtière en d’autres points du monde.

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Copyright information

© International Association of Engineering Geology 1976

Authors and Affiliations

  • Shlemon R. J. 
    • 1
  • Capacete J. L. 
    • 2
  1. 1.Newport BeachCaliforniaU.S.A.
  2. 2.SanturceU.S.A.

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