HULHULE-MALE’ BRIDGE PROJECT

EIA for the proposed Hulhule-Male’ Bridge Project
4.3 Topography, Geology and Soils
4.3.1 Geology
4.3.1.1 Geology of Male’ Region
Recent findings on the geological history of Maldivian Atolls, including Male’ Atoll, indicate
that it differs from the traditionally believed subsidence model proposed by Darwin. Instead, it is
believed to have been formed through carbonate accumulation of over 3000 m throughout the
Tertiary period (66 million to 2.58 million years ago), through various phases of aggradation and
progradation associated with sea level variations (Aubert and Droxler, 1992; Purdy and Bertram,
1993; Belopolsky and Droxler, 2003). During the Quaternary Period (2.6 million years to present
day), reef growth was dominated by vertical growth associated with sea level fluctuations. The
present morphology of Maldives is the result of vertical growth during the Holocene Period over
the last 10,000 years (Kench et al., 2009). The thickness of the Holocene growth was measured
between 12 to 14 m (Gischler et al., 2008; Kench et al., 2009). The modern islands themselves
are known to have been formed between 5,500 - 4000 years across the infilled lagoon, and
stabilised around 3,500 years ago (Kench et al., 2005).
The Male’ Island geology was studied to a limited extend by Dr. André Droxler (Flury, 2009). In
this study, based on borehole studies undertaken in the past, he established that Male’ Island is
built upon the Holocene reef formation developments on top of a Pleistocene platform. Two
Pleistocene edifices were identified: a wide section on southern half of Male’ and a narrow
section on the northern half. The southern section is about 10-13 m deep but the northern section
was identified as 22-27 m deep. Radio-carbon dating and borehole surveys by Riyaz et al.,
(2008) confirmed these findings (See Figure 4.2). The Halocene growth usually contained
unconsolidated sediments while the Pleistocene layers contained karstified limestone. As found
in other studies (for example Gischler et al., 2008; Kench et al., 2009) the lower layers contained
sediments about 11,000 to 8000 years old and the upper layers contained sediments about 6500
years old.
Male’ Island is a heavily modified island with numerous man made developments. The reef
system has been reclaimed up to 45-50% of its original size. Shore protection has been
constructed all around the island. All the remaining shallow reef areas have been dredged to
create harbours. It is also described as the most densely populated city in the world with over
50,000 per sq km. At least 60% of the island now comprises of buildings ranging between 1 to
15 floors.
The reef system of Male’ is moderate, covering over 231 Ha within the shallow reef. The length
of the reef system is 2.02 km and width at its width point is 1.4 km. The reef system and the
island are oriented in an East-west direction. The outer reef line extends a further 80 m towards
Prepared by: CDE Consulting & China Shipping Environment Technology
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