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Title: Hydrothermal vent fauna and fossilisation
Author: Anderson, Louise Margaret.
ISNI:       0000 0001 3422 1387
Awarding Body: Royal Holloway, University of London
Current Institution: Royal Holloway, University of London
Date of Award: 2003
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Hydrothermal vents and their associated fauna were first discovered in 1977. An unusual, diverse fauna thrives around these vents. The dynamic and unpredictable nature of volcanism, fluid chemistry and temperature around vents mean these faunal habitats remain for a maximum of -20 years. This study examines fossilisation of vent fauna from five localities of varying tectonic setting and age: the Mothra Vent Field, Endeavour Segment, Juan de Fuca Ridge; 'Feather Duster' vent site, 11oN East Pacific Rise; 'MESO' zone, Central Indian Ridge; Roman Ruins vent site, PACMANUS, eastern Manus Basin; and the Kambia massive sulphide deposit, Troodos ophiolite, Cyprus. No shelly fauna (i.e. gastropods or bivalves) were found. The majority of the fossils found were vestimentiferan tubeworm tubes. Diagnostic features for these include at least one of the following: surface striations/longitudinal ridges; internal septa and lateral flange structures. Extensive SEM and mineral mapping have highlighted specific mineral patterns on fossil worm tube surfaces for both early and late stage fossilised material. An order of mineralisation is presented for early-mineralised material. Several new and unique fmds are reported here. A specimen of a predatory (?) ammonite preserved in pyrite from a late Cretaceous vent deposit provides evidence of an additional trophic group to fossil vent communities and introduces a new, challenging palaeoenvironment for ammonites. Delicate internal septa from the interiors of fossil tubeworm tubes (preserved in silica), suggest the tubeworm Ridgeia piscesae secretes basal clumps to support its body within the tube. Previously unreported fossilised soft body parts infer either bacterial inducement of mineralisation of worm body surfaces, or protection of those surfaces by bacteria. Stable isotopes of carbon, nitrogen and sulphur were used as an additional tool for the study of both animal tissues, fossilised worm tubes and sulphide samples. Results for Ol3C and olsN of animal tissues agreed with previous work. Ol3C and Ol~ for fossilised material suggest a bacterially fractionated worm signature. 034S values for sulphides suggest a volcanic source for sulphur, with little evidence for bacterial fractionation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available