basement through the Cenozoic lithologies.
Background info:
The basement geology of New Zealand Port Waikato has settled on
Jurassic basement(Mesozoic) it contains sandstone and siltstone
with conglomerate and thin tuff beds and carbonaceous in places
it’s Terrestrial is about carbonaceous sandstone, conglomerate and
siltstone at top includes vegetation and coal seams. Several
lithologies that ranges from Jurassic (Mesozoic) rocks to recent
deposits can be discovered in the port Waikato region. The mainly
rock type of Jurassic basement rocks is Murihiku Terrane rocks
(greywacke) that are bordered to the north by the Waikato fault are
the Jurassic basement rocks.
（Paleogeography of Late Eocene AWHI
to earliest Miocene Te Kuiti Group, central-western North
Island）
Huriwai Group which is from upper Jurassic age overlays the
basement rocks. Materials from the tertiary period that belong to
the Te Kuiti Group overlay the Upper Jurassic basement rocks and
these sedimentary rocks are from the Oligocene age to the Lower
Miocene age. In addition, sedimentary rocks from the Lower Miocene
age that belong to the Waitemata Group overlays the Te Kuiti Group
(in terms of the cliff lines around Auckland and the east coast
base formation). Eventually, these rocks are then overlaid by the
quaternary sediments. It also between the Waitemata group and the
Pliocene deposits, there are also the sequences of Pliocene
deposits. The Port dunes is from the Late Quaternary sediments
which is in mobile and Modern fixed river dunes, there are locally
paleosols and peat, loose and poorly consolidated. The Jurassic
basement which is formed by the greywacke, also as known as the
Murihiku Terrane rocks, has a 15 kilometers thickness and these
significant basement deposits mainly contain the well stratified
volcanic-derived sandstones, mudstones and a few conglomerates.
They also form some large scale folding such as Waikato fault. The
Huriwai group which is from the late Jurassic age contains
siltstones, sandstones and conglomerates. The Jurassic is overlayed
by the tertiary deposited, they are deposit from Oligocene to Lower
Miocene sedimentary rocks which is from the Te Kuiti Group, the Te
Akatea Siltstone is the youngest sedimentary rock, and the Aotea
Formation is upon the Te Akatea Siltstone contains Waimai Limestone
Member crystalline limestones, the Whaingaroa Siltstone is above
and covered by Glen Massey Formation from early Oligocene 34~24
million years ago with Massive and bluff-forming sandstone and
elgood Limestone Member. Waitemata Group is overlies the Te Kuiti
Group from the early Miocene also the rock type dominated by
calcareous sandstone and mudstone they usually have significant
clay seams cause instability of landform and potential landslide.
After the Waitemata Group is followed by Pliocene Kaawa Formation
it’s the latest epoch in the Tertiary has slightly calcareous grey
sorted carbonaceous sandstone with well sorted, non-calcareous
yellow sands. Pliocene Kaawa Formation are overlayed by the Awhitu
Group in sequence from Late Pliocene(5.3 million to 2.6 million
years BP) to early Pleistocene contains Kaihu Sand from
dune-bedding also the Pumiceous ignimbrite, Kidnappers Tephra,
Brown-orange sands. On the top of all other sediments is Kaihu
Group from Quaternary(2.5 million years ago) Kaihu Group contains
Clayey pumiceous sands from Pleistocene also these fixed dune sand
from the Holocene.
- Detailed Descriptions Of Port Waikato Rock Types From Jurassic Basement Through The Cenozoic Lithologies Background In 1 (482.66 KiB) Viewed 416 times
landscape and lithology types (relating surface expression to
lithology). Use your understanding of lithology types to link to
landscape units identified at Sunset Station (and the Waikawau
Valley area). Refer to the slides contained in the Port Waikato
Rock Samples file.
Jurassic Murihiku Terrane rocks Rock type: Greywacke Dark grey, indurated, medium to coarse-grained sandstone.
Tertiary Glen Massey Formation Fine to medium-grained, light brown, massive sandstone. Contains abundance of glauconite.
Tertiary Glen Massey Formation Medium-to coarse-grained, grey, impure crystalline limestone.
Tertiary Te Akatea Siltstone Fine-grained, light grey, very calcareous siltstone. Contains fossils.
Te Kuiti Group Jurassic Slope Profile 100 PORT WAIKATO metres Pleistocene Te Akatea Fm 73/55° 70/43⁰ 90/78° D. Grass covered Pleistocene sands Grass covered siltstone 90 Aotea Fm - Aeotea 70/38° G. Sandy siltstone 80 siltstone Grass covered bench Blocky limestone 70 Aotea Fm - Waimai Massive Limestone m 55-10⁰ limestone 60 Whaingaroa sist 69 50 26⁰ B. Calcareous Sst Glen 40 Massey Rock unit ABCDEFG Grass covered bench Intact rock, on weathered Sst 10 10 5 18 8 12 10 strength R Weathering 9 9 5 9 9 9 9 Spacing of ints 30 21 18 30 21 21 18 Jnt orientation 16 14 14 14 14 14 16 Width of joints 5 5 5 6 6 6 6 Continuity of joints Outflow of groundwater Fm 81/80 A. Massive calcareous Sst 30 6 5 5 7 6 5 5 20 5 5 3 6 6 6 6 Boulder-strewn terracetted slope, grass-covered 10 Total rating 81 69 55 90 70 73 70 Smooth grassed slope with few irregularities 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 metres Fig. 3. A slope profile in sedimentary rocks from Port Waikato, New Zealand, showing the slope angles and mass strength rating for exposed rock units. From Selby (1980)