Uranium-series dating and growth characteristics of the deep-sea scleractinian coral: Enallopsammia rostrata from the Equatorial Pacific Fanny Houlbre `que a,b, * , Malcolm McCulloch c,d , Brendan Roark e , Tom Guilderson f , Anders Meibom g , Justine Kimball a , Graham Mortimer c , Jean-Pierre Cuif h , Robert Dunbar a a Geological and Environmental Sciences, Stanford University, Stanford, CA 95064, USA b International Atomic Energy Agency, Marine Environment Laboratories, MC 98012 Monaco, Monaco c Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia d School of Earth and Environment and ARC Centre of Excellence in Coral Reef Studies, University of Western Australia, Crawley, Western Australia 6009, Australia e Texas A&M University, Department of Geography, Ocean Drilling & Sustainable Earth Science, College Station, TX 77843, USA f Center for Accelerator Mass Spectrometry, LLNL, L-397 7000 East Avenue, Livermore, CA 94551, USA g UMR 8148, Interactions et Dynamique des Environnement de Surface, Universite ´ Paris XI, Orsay, France h Laboratoire d’E ´ tude de la Matie `re Extraterrestre USM 0205, Muse ´um National d’Histoire Naturelle, Paris, France Received 20 January 2009; accepted in revised form 13 January 2010; available online 20 January 2010 Abstract The deep-sea coral, Enallopsammia rostrata, a member of the Dendrophylliidae family, is a major structure-forming species that creates massive dendroid colonies, up to 1 m wide and 0.5 m tall. Living colonies of E. rostrata have been collected using the PISCES submersibles from three locations from 480 to 788 m water depth in the Line Islands (160°W) in the Equatorial Pacific. We have applied to these colonies a high sensitivity, low blank technique to determine U-series ages in small quantities (70 ± 15 mg) of modern and near modern calcareous skeletons using MC-ICP-MS (Multi-collector Inductively Coupled Plas- ma Mass Spectrometer). The application of this method to living slow-growing colonies from a range of sites as well as the observations of axial growth patterns in thin sections of their skeletons offer the first expanded and well constrained data on longevity, growth pattern and mean growth rates in E. rostrata. Absolute dated specimens indicate life spans of colonies rang- ing from 209 ± 8 yrs to 605 ± 7 yrs with radial growth rates from 0.012 to 0.072 mm yr 1 and vertical extension rates from 0.6 to 1.9 mm yr 1 . The linear growth rates reported here are lower than those reported for other deep-sea scleractinian corals (Lophelia pertusa and Madrepora oculata). The U-series dating indicates that the growth ring patterns of E. rostrata are not consistent with annual periodicity emphasizing the importance of absolute radiometric dating methods to constrain growth rates. Slow accretion and extreme longevity make this species and its habitat especially vulnerable to disturbances and impacts from human activities. This dating method combined with observation of growth patterns opens up new perspec- tives in the field of deep-sea corals since it can provide quantitative estimates of growth rates and longevity of deep-sea corals in general. Ó 2010 Elsevier Ltd. All rights reserved. 1. INTRODUCTION Deep-water corals have been known by fishermen and benthic specialists for centuries (Zibrowius, 1980). However, 0016-7037/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.gca.2010.01.017 * Corresponding author. Address: Geological and Environmental Sciences, Stanford University, Stanford, CA 95064, USA. Tel.: +1 377 97 97 72 58. E-mail address: F.Houlbreque@iaea.org (F. Houlbre `que). www.elsevier.com/locate/gca Available online at www.sciencedirect.com Geochimica et Cosmochimica Acta 74 (2010) 2380–2395