Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 


Clues to Auckland’s past uncovered at Buckland’s Beach


Click for big version.

Clues to Auckland’s past uncovered at Buckland’s Beach

“A small intertidal reef at the north end of Bucklands Beach, Pakuranga, holds important clues to what Auckland was like 5000 years ago,” says Auckland marine geologist Bruce Hayward of Geomarine Research. Together with local marine biologist Margaret Morley they have identified fossil shells in the rock as those that lived below low tide in the strong current-swept entrance of the Tamaki Estuary. They recently presented their results at the New Zealand Geoscience Society Conference in Hamilton.

A fossil dog-cockle, still in life position, has been radiocarbon dated at Waikato University at 5000 years old. “It tells us that sea level was at least 1.5 m higher then than it is today,” said Dr Hayward. “The flat land behind Bucklands Beach now covered in houses and shops built up at the back of the beach at that time.”

“The Bucklands Beach reef rock is largely composed of shells and basalt pebbles eroded from Browns Island. These would have been swept into the Tamaki Estuary by strong northerly storms and tides. Today, volcanic rock from Browns Island is not washing into the Tamaki, but 5000 years ago there was no Rangitoto as it did not erupt in the middle of the harbour until 600 years ago. With no Rangitoto present, the eastern bays from Mission Bay to Musick Pt would have been far more exposed and it may have been possible to surf at these beaches during big storms,” speculates Hayward.

“The north side of Browns Island was much more exposed prior to eruption of Rangitoto. Its soft volcanic ash cliffs eroded back rapidly at a rate of 1 m every 20 years and some of this eroded volcanic sand and pebbles ended up on the coast at St Heliers, Bucklands and Eastern beaches. The sandstone cliffs from Orakei to Eastern Beach would also have been eroding much faster prior to Rangitoto’s appearance. Today erosion has largely stopped where the Tamaki Drive has been built around their foot. Elsewhere, such as at Archilles and Musick points, erosion has slowed with these steep cliffs now partly stabilised by vegetation growth.”

“The intertidal reef at Bucklands Beach has been cemented together by the growth of cream crystals of a mineral called motukoreaite, described on Browns Island some 25 years ago by Auckland University scientists. This mineral is now recognised in marine deposits of volcanic sediment all around the world.”

ENDS

© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Wine: 20% Of Marlborough Storage Tanks Damaged By Quake

An estimated 20 percent of wine storage tanks in the Marlborough region, the country’s largest wine producing area, have been damaged by the impact of the recent Kaikoura earthquake. More>>

ALSO:

ACC: Levy Recommendations For 2017 – 2019 Period

• For car owners, a 13% reduction in the average Motor Vehicle levy • For businesses, a 10% reduction in the average Work levy, and changes to workplace safety incentive products • For employees, due to an increase in claims volumes and costs, a 3% increase in the Earners’ levy. More>>

Women's Affairs: Government Accepts Recommendations On Pay Equity

The Government will update the Equal Pay Act and amend the Employment Relations Act to implement recommendations of the Joint Working Group on Pay Equity. More>>

ALSO:

Immigration: Increase In Seasonal Workers For RSE

The current cap will be increased by 1,000 from 9,500 to 10,500 RSE workers for the 2016-17 season. Mr Woodhouse says the horticulture and viticulture industry is New Zealand’s fourth largest export industry, producing almost $5 billion in exports. More>>

ALSO:

Hurunui: Crown Irrigation Invests Up To $3.4m In North Canterbury

Crown Irrigation Investments will invest up to $3.4m in the Hurunui Water Project, an irrigation scheme that will be capable of irrigating up to 21,000 hectares on the south side of the Hurunui River in North Canterbury. More>>

ALSO:

Not So Great:Butterfly Eradication Success

The invasive pest great white butterfly has been eradicated from New Zealand in a world-first achievement, Primary Industries Minister Nathan Guy and Conservation Minister Maggie Barry say. More>>

Gordon Campbell: On The Government’s Tax Cuts Fixation

Long before the earthquake hit, the dodginess of the government tax cuts programnme was evident in the language of its packaging. It is being touted as a “tax cuts and family care” package... More>>

ALSO:

Get More From Scoop

 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news