Achilles Point (Te Pane o Horoiwi – The head of Horoiwi) is a rocky point on the headland at the eastern end of the small sandy beach named Ladies Bay, Auckland, New Zealand. The name 'Te Pane o Horoiwi' can also sometimes refer to the whole headland between St Heliers and Tamaki River estuary. Achilles Point is named after a ship called HMNZS Achilles (70) which defeated the German pocket battleship Admiral Graf Spee in 1939. The headland, from the point round to the Tamaki heads, was previously known as Te Pane o Horoiwi, named after Horoiwi who arrived in New Zealand on the Tainui canoe (waka).
Looking east from St Heliers Bay towards the headland which juts out towards Rangitoto. Ladies Bay, a small sandy beach just 150 meters long, is just out of view around the 'Te Wharau' point. Achilles Point, is at the eastern end of Ladies Bay. A volcanic crater extends inland from the water tower in the south (right of picture) to the cliff edge in the north (left of picture) with volcanic rock falling down to the beach below just east of Ladies Bay.View from the lookout, looking east over Gentleman's Bay towards Tamaki point, the entrance to the Tamaki River estuary, then on the horizon Musick Point
Ladies Bay is a secluded beach, below steep cliffs, on the headland west of the lookout over Achilles point. Both Ladies Bay and further to the east, the more secluded Gentleman's Bay beach are unofficially places where nudists can often be found enjoying the sun and sand however the fine for indecent exposure is $200.[1] The secluded bays are also popular with the male gay community.
Glover Park is an ancient volcanic crater which erupted more than 45,000 years ago.[2]: 233 The volcanic tuff ring crater is also known in Māori language as Whakahumu or geologically as the 'St Heliers explosion crater'. It is found in the center of the headland between West Tamaki Head and the eastern end of St Heliers Bay beach. It was filled in during the 1950s to form a public sports field. Before that it formed a seasonal shallow lake or swamp.
High above Gentleman's Bay, an abandoned building site with crumbling cliffs
The seaward side of the tuff crater is falling away down the coastal cliffs to 'Gentleman's Bay' far below. The tuff ring is made from ash and ejected material. The cliffs were there before the volcano erupted so the volcanic rock draped over the clay hill that once existed before sea levels rose and began eroding it away to become the steep cliffs we see today. Some volcanic rocks can be found on the beach below – some fragments ejected from deep in the earth, or blocks of tuff ring that were once perched on top of the cliff. Rangitoto Island is directly to the north, however Rangitoto is a recent eruption (600 to 550 years ago)[3] and was not always there to shelter the cliffs from powerful wave action. There is an old concrete water tower built on the tuff ring formed around the edge of the crater opposite the seaward side.
Looking north from Karaka Bay towards Tamaki Point (1 km from Achilles Point)
Going east, past Ladies Bay and Gentleman's Bay, we round the West Tamaki Head into the Tamaki Estuary. It is here we find an excellent example of the grey coloured 'Parnell Grit' accessible from Karaka Bay. 'Parnell Grit', is a brittle sedimentary rock containing fragments of scoria, andesite, and pumice.
At low tide there is an interesting walk from Ladies Bay along the base of the cliffs to St Helier's Bay. The rocky shoreline overlooks the Waitemata Harbour which itself occupies a drowned valley system cut in marine sediments of Miocene Age (15–25 million years ago). Generally, around Auckland these soft Miocene sediments are alternating Waitemata series sandstone and mudstone with more massive beds of sandstone sometimes with minor occurrences of limestone.[4] The concretions that can be easily seen, are formed by the action of ground water with dissolved minerals (mainly calcium carbonate of which limestone is made) percolating through the layers. Calcium carbonate is an important component of concrete and fills in the pore spaces between grains of sediment thereby cementing the grains together and making them more durable against erosion.
Glover Park volcano formed from a phreatomagmatic eruption leaving a basalticmonogenetic volcanic crater up to 300 m (980 ft) in maximum diameter, surrounded except to the north-east by tuff deposits that extend about 500 m (1,600 ft) to the east and south.[2]: 231–3 The presence of overlying Rotoehu tephra on a drill ore means the volcano last erupted more than 45,000 years ago, but the age is unclear within a wide range. The cliff retreat with raising sealevels of Achilles Point has meant, as already mentioned, that the tuff deposits 30 m (98 ft) up the cliffs,[2]: 233 as they erode, fall onto the sea rock platform (see photos below). This has resulted in the discovery that a distinctive lithic clast in the tuff that contained shell fragments was strong evidence that the erupted magma traversed the eastern border of the ophioliticDun Mountain-Maitai Terrane.[2]: 238
Referencesedit
^MacIntyre, Jenny (10 February 2008). "'Dirty blokes' ruining bare-all bay". The New Zealand Herald. Retrieved 15 September 2011.
^ abcdSpörli, K. B.; Black, P. M.; Lindsay, J. M. (2015). "Excavation of buried Dun Mountain–Maitai terrane ophiolite by volcanoes of the Auckland Volcanic field, New Zealand". New Zealand Journal of Geology and Geophysics. 28 (3): 229–243. doi:10.1080/00288306.2015.1035285.
^Devora (2020). Rangitoto: Odd one out. The story of Auckland's largest volcano. Devora Fact Sheet 03."DEVORA Fact Sheet 3 - Rangitoto: Odd One Out". Retrieved 9 December 2023.
Cross-section of concretion snapped off at cliff wall.
Concretions all line up in the cliff wall.
1859 map showing the volcanoes and lava flows. Glover Park volcano is to the upper right on the shores of the Waitematā Harbour.
The rocks between the point and St Heliers Bay. Layers of sedimentary rock strata.
The rocks between the point and St Heliers Bay. White siltstone layer.
The rocks between the point and St Heliers Bay. The concretions are scattered and looking like fossilised logs, long after the supporting sandstone has been eroded away by the waves.
The projections are known as concretions and are all on the same horizontal layer. Sometimes they might snap off. More often, the softer stone erodes away completely, leaving them resting on the surface a few meters lower.
Close up of sandstone and mudstone layers
Achilles Point from the viewing platform - looks like the bow of a ship.
Ladies Bay
Glover Park crater with housing and water tower on the tuff ring
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Achilles Point Te Pane o Horoiwi The head of Horoiwi is a rocky point on the headland at the eastern end of the small sandy beach named Ladies Bay Auckland New Zealand The name Te Pane o Horoiwi can also sometimes refer to the whole headland between St Heliers and Tamaki River estuary Achilles Point is named after a ship called HMNZS Achilles 70 which defeated the German pocket battleship Admiral Graf Spee in 1939 The headland from the point round to the Tamaki heads was previously known as Te Pane o Horoiwi named after Horoiwi who arrived in New Zealand on the Tainui canoe waka Looking east from St Heliers Bay towards the headland which juts out towards Rangitoto Ladies Bay a small sandy beach just 150 meters long is just out of view around the Te Wharau point Achilles Point is at the eastern end of Ladies Bay A volcanic crater extends inland from the water tower in the south right of picture to the cliff edge in the north left of picture with volcanic rock falling down to the beach below just east of Ladies Bay View from the lookout looking east over Gentleman s Bay towards Tamaki point the entrance to the Tamaki River estuary then on the horizon Musick Point Ladies Bay is a secluded beach below steep cliffs on the headland west of the lookout over Achilles point Both Ladies Bay and further to the east the more secluded Gentleman s Bay beach are unofficially places where nudists can often be found enjoying the sun and sand however the fine for indecent exposure is 200 1 The secluded bays are also popular with the male gay community Glover Park is an ancient volcanic crater which erupted more than 45 000 years ago 2 233 The volcanic tuff ring crater is also known in Maori language as Whakahumu or geologically as the St Heliers explosion crater It is found in the center of the headland between West Tamaki Head and the eastern end of St Heliers Bay beach It was filled in during the 1950s to form a public sports field Before that it formed a seasonal shallow lake or swamp High above Gentleman s Bay an abandoned building site with crumbling cliffs The seaward side of the tuff crater is falling away down the coastal cliffs to Gentleman s Bay far below The tuff ring is made from ash and ejected material The cliffs were there before the volcano erupted so the volcanic rock draped over the clay hill that once existed before sea levels rose and began eroding it away to become the steep cliffs we see today Some volcanic rocks can be found on the beach below some fragments ejected from deep in the earth or blocks of tuff ring that were once perched on top of the cliff Rangitoto Island is directly to the north however Rangitoto is a recent eruption 600 to 550 years ago 3 and was not always there to shelter the cliffs from powerful wave action There is an old concrete water tower built on the tuff ring formed around the edge of the crater opposite the seaward side Contents 1 Geology 2 References 3 External links 4 GalleryGeology edit nbsp Looking north from Karaka Bay towards Tamaki Point 1 km from Achilles Point Going east past Ladies Bay and Gentleman s Bay we round the West Tamaki Head into the Tamaki Estuary It is here we find an excellent example of the grey coloured Parnell Grit accessible from Karaka Bay Parnell Grit is a brittle sedimentary rock containing fragments of scoria andesite and pumice At low tide there is an interesting walk from Ladies Bay along the base of the cliffs to St Helier s Bay The rocky shoreline overlooks the Waitemata Harbour which itself occupies a drowned valley system cut in marine sediments of Miocene Age 15 25 million years ago Generally around Auckland these soft Miocene sediments are alternating Waitemata series sandstone and mudstone with more massive beds of sandstone sometimes with minor occurrences of limestone 4 The concretions that can be easily seen are formed by the action of ground water with dissolved minerals mainly calcium carbonate of which limestone is made percolating through the layers Calcium carbonate is an important component of concrete and fills in the pore spaces between grains of sediment thereby cementing the grains together and making them more durable against erosion Glover Park volcano formed from a phreatomagmatic eruption leaving a basaltic monogenetic volcanic crater up to 300 m 980 ft in maximum diameter surrounded except to the north east by tuff deposits that extend about 500 m 1 600 ft to the east and south 2 231 3 The presence of overlying Rotoehu tephra on a drill ore means the volcano last erupted more than 45 000 years ago but the age is unclear within a wide range The cliff retreat with raising sealevels of Achilles Point has meant as already mentioned that the tuff deposits 30 m 98 ft up the cliffs 2 233 as they erode fall onto the sea rock platform see photos below This has resulted in the discovery that a distinctive lithic clast in the tuff that contained shell fragments was strong evidence that the erupted magma traversed the eastern border of the ophiolitic Dun Mountain Maitai Terrane 2 238 References edit MacIntyre Jenny 10 February 2008 Dirty blokes ruining bare all bay The New Zealand Herald Retrieved 15 September 2011 a b c d Sporli K B Black P M Lindsay J M 2015 Excavation of buried Dun Mountain Maitai terrane ophiolite by volcanoes of the Auckland Volcanic field New Zealand New Zealand Journal of Geology and Geophysics 28 3 229 243 doi 10 1080 00288306 2015 1035285 Devora 2020 Rangitoto Odd one out The story of Auckland s largest volcano Devora Fact Sheet 03 DEVORA Fact Sheet 3 Rangitoto Odd One Out Retrieved 9 December 2023 Geological Map of New Zealand Volcanoes of Auckland A Field Guide Hayward B W Auckland University Press 2019 335 pp ISBN 0 582 71784 1 External links editArchaeology and History of St Heliers Auckland Geology of the headland Point to point walkway ARC St Heliers to Churchill park through the crater at Glover Park Explanation of concretions Point to Point walkway The full point to point walk is approximately 7 5km long starting at the popular St Heliers Bay and finishing at Point England Allow three to four hours Gallery editGeological features between Ladies Bay and St Heliers Bay nbsp Sandstone and mudstone layers nbsp Close up of white siltstone in cliff nbsp White rock broken away nbsp Discoloration of crumbling white siltstone layer nbsp Cross section of concretion snapped off at cliff wall nbsp Concretions all line up in the cliff wall nbsp 1859 map showing the volcanoes and lava flows Glover Park volcano is to the upper right on the shores of the Waitemata Harbour nbsp The rocks between the point and St Heliers Bay Layers of sedimentary rock strata nbsp The rocks between the point and St Heliers Bay White siltstone layer nbsp The rocks between the point and St Heliers Bay The concretions are scattered and looking like fossilised logs long after the supporting sandstone has been eroded away by the waves nbsp The projections are known as concretions and are all on the same horizontal layer Sometimes they might snap off More often the softer stone erodes away completely leaving them resting on the surface a few meters lower nbsp Close up of sandstone and mudstone layers nbsp Achilles Point from the viewing platform looks like the bow of a ship nbsp Ladies Bay nbsp Glover Park crater with housing and water tower on the tuff ring 36 50 36 S 174 51 50 E 36 843390 S 174 863800 E 36 843390 174 863800 Retrieved from https en wikipedia org w index php title Achilles Point amp oldid 1218521164, wikipedia, wiki, book, books, library,
