Chapter I Intro & Objectives - SPREP

PHOENIX ISLANDS PROTECTED AREA MANAGEMENT PLAN
Chapter III. Background, 1. Physical Setting of the Islands
Draft 1 March 2007
In 2002, seawater temperature loggers were deployed at Abariringa (Kanton) (3 sites); Orona
(2 sites); Nikumaroro (2 sites); Manra (1 site); Enderbury (1 site); Rawaki (Phoenix) (1 site)
(Obura and Stone 2003). No temperature loggers were deployed at Birnie.
C. BATHYMETRIC
In 1974, the Committee for Co-ordination of Joint Prospecting for marine resources in the
South Pacific (CCOP/SOPAC) noted that Nauru through the Phoenix Islands to the Line
Islands had the greatest potential for offshore phosphate at depths of 400 m (Teiwaki 1988).
It was recommended that surveys for the phosphate be initiated.
Tiffin (1981) summarized findings of KI-81(3) survey of Kiribati waters for manganese
nodules that were completed from 7 to 17 May 1981. Tiffin (1981) noted that Cruise No. 37
included an area east of the Phoenix Islands. For KI-81(3), four stations were surveyed.
However, based on the cruise track, none appeared to be within the EEZ of the Phoenix
Islands, even though the cruise was titled, “Kiribati Phoenix Islands manganese nodule
survey”.
Teiwaki (1988) noted that there have been several seabed surveys for manganese resources.
These have included surveys by CCOP/SOPAC, Minex, Japan, West German, and the U.S.A.
Teiwaki (1988) noted that only the CCOP/SOPA and Minex surveys were officially
recognized by the Government of Kiribati.
Aslanian et al (1988b) examined cumulative volcano amplitude (CVA) and CVA maxima
related to seamounts in the central Pacific, including the Phoenix Islands. There is a CVA
maximum underlined by flowlines from the Phoenix Islands. The Mid-Cretaceous ridges of
the Phoenix fracture zone intersect flowlines at the biggest and brightest CVA maxima in the
vicinity of Rarotonga and Rurutu. In addition, Phoenix Islands crustal flowlines appeared to
have a role in both the Mehetia and MacDonald CVA maxima, however, cannot be linked to
both hot-spots. Aslanian et al (1988b) concluded that hot-spotting was flawed by errors and
that its application was not age independent.
Cronan et al (1991) reported on manganese (Mn) nodules in the EEZ around the Phoenix
Islands (see also Cronan 1987; Kinoshita and Tiffin 1993; JICA et al 2005; see Figure III-
1.19). These were based on Japanese cruises (Glasby 2002). The highest abundance (>25
kg/m 2 ) was in a small area around 5 0 S, 170 0 W (Cronan et al 1991; on the southern Phoenix
Islands area according to Cronan and Hodkinson 1989 and 1991). On the northern area,
abundance was less than 5 kg/m 2 (Cronan 1987), but nickel (Ni) and copper (Cu) content was
high in the north and decreased towards the south (see also Cronan and Hodkinson 1989 and
1991). Cobalt (Co) grades were generally low overall. Average Co content was 0.83 percent
(Cronan and Hodkinson 1989 and 1991).
Figure III-1.19. The abundance of nodules in the EEZ around the Phoenix Islands
(Source: Cronan et al 1991 and Cronan and Hodkinson 1989 and 1991).
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