BLUFF HEAD FORMATION -Db (CEDD)
The oldest stratum in Hong Kong, as proven
by existing fossil evidence, is a bed of Devonian sedimentary rock. It is
mainly outcropped on both sides of Tolo Channel. Sedimentary pyroclastic rocks
found around Pak Sha Tau and Wong Chuk Kok Tsui on the northern shore are
called Wong Chuk Kok Tsui Formation. They are primarily sandstone, pebbly
sandstone and conglomerate. The best outcropped areas of this formation can be
found around Wong Chuk Kok Tsui at the northern tip of the channel. Influenced
by the folding and staggering action of geological movements, the beddings are
almost vertical. It is a breathtaking sight.
The rich Devonian fossils found in Tolo
Channel provide a strong basis for determining geological age and sequence
stratigraphy. They also help us understand how Hong Kong's natural environment
evolved during that time. (HK GLOBAL GEOLOGY PARK)
Ping Chau, or Tung Ping Chau to
differentiate from Peng Chau, sits in Mirs Bay of the northeastern waters. It
is the easternmost outlying island of Hong Kong. This crescent-shaped island,
measuring 600 metres long and 200 metres wide, is renowned for strange rock
formations. Unlike most other rock types across the territory, the island is
made up of sedimentary rock including siltstone, dolomitic siltstone, mudstone
and chert. This sedimentary rock strata is known as Ping Chau Formation.
Many
extremely well preserved fossils have been found within the formation. Fossil studies,
investigations of rock properties and regional geophysics, as well as research
in climatic changes during ancient times have confirmed that this formation is
the product of sedimentation which took place in Early Tertiary. Layer upon
layer of rock form a bewildering structure. The strata looks just like a huge
book, guarding great mysteries of geological history within its numerous pages.
Since no sediments after Early Tertiary have successfully solidified into
enduring rock, Ping Chau Formation is the youngest rock in Hong Kong's
geological history. Tung Ping Chau is a popular holiday destination. Its many
fascinating attractions, such as wave erosion landscape, the shale that
resembles a layered sponge cake and the unusually flat lay of the island
itself, have drawn thousands of visitors to the island.
