From the Mantle to Microbes: The Lost City Hydrothermal Field

Deborah Kelley

doi:10.5670/oceanog.2005.23

Abstract

From the Mantle to Microbes: The Lost City Hydrothermal Field

Highlights

F O R OVER T WO D EC AD E S, explorers of the deep ocean have been enthralled by volcanically driven black smoker hydrothermal systems hosting organisms that live under some of the most extreme conditions on Earth (e.g., Corliss et al, 1979; Jannasch and Mottle, 1985; Grassle, 1986; Delaney et al, 1992; Humphris et al, 1995; Humphris and Tive, 2000; Van Dover, 2000; German et al, 2004; Wilcock et al, 2004)
The Atlantis Massif is not formed by volcanic eruptions, but instead by extreme crustal extension and long-lived faulting and uplift
Long-lived faulting, extreme crustal extension, and exposure and alteration of shallow mantle material is characteristic of submarine mountains such as the Atlantis Massif, and the processes involved in their construction are probably critical to formation of Lost City-like systems

Summary

THE LOST CITY HYDROTHERMAL FIELD

F O R OVER T WO D EC AD E S , explorers of the deep ocean have been enthralled by volcanically driven black smoker hydrothermal systems hosting organisms that live under some of the most extreme conditions on Earth (e.g., Corliss et al, 1979; Jannasch and Mottle, 1985; Grassle, 1986; Delaney et al, 1992; Humphris et al, 1995; Humphris and Tive, 2000; Van Dover, 2000; German et al, 2004; Wilcock et al, 2004). MOUNTAINS OF THE DEEP The Lost City Hydrothermal Field (LCHF) is located 15 km west of the spreading axis of the Mid-Atlantic Ridge at 30°N, near the summit of the Atlantis Massif (Blackman et al, 2002; Kelley et al, 2001, 2005) The relief of this mountain is similar to that of Mt. Rainier, rising nearly 4000 m above the seafloor over a horizontal distance of ~20 km (Figure 1). Long-lived faulting, extreme crustal extension, and exposure and alteration of shallow mantle material is characteristic of submarine mountains such as the Atlantis Massif, and the processes involved in their construction are probably critical to formation of Lost City-like systems. This new venting system, called Lost City, is unlike any environment ever visited. These reactions are dominated by serpentinization reactions, which are driven by the instability of mantle-hosted olivine and

Fueled by cooling of submarine volcanoes

Volatile Compositions

Chimney Mineralogy

Findings

These Archaea show a surprisingly low