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

 

Warming: Warming Signs From State Of Climate Report

Climate data from air, land, sea and ice in 2013 'reflect trends of a warming planet' -- says the latest State of the Climate report, launched by U.S. and New Zealand scientists. More>>

ALSO:

Scoop Business: Embrace Falling Home Affordability, Says NZIER

Despair over the inability to afford a house is misplaced and should be embraced as an opportunity to invest in more wealth-creating activity, says the principal economist at the New Zealand Institute of Economic Research, Shamubeel Eaqub. More>>

Productivity Commission: NZ Regulation Not Keeping Pace

New Zealand regulators often have to work with out-of-date legislation, quality checks are under strain, and regulatory workers need better training and development. More>>

ALSO:

Callaghan Innovation: Investment To Help Deepen Innovation Reporting

Callaghan Innovation, the government’s high tech HQ for Kiwi business, is to help deepen New Zealand media coverage of the commercialisation of innovation through an arms-length partnership with independent business news service BusinessDesk. More>>

ALSO:

Tax Credits, Grants: Greens $1Bn R&D Plan

In the Party’s headline economic announcement, the Greens have launched their plan to build a smarter, more innovative economy which has as its centrepiece an additional $1 billion of government investment in research and development (R&D) above current spend, including tax breaks for business. More>>

ALSO:

Inflation: CPI Increases 0.3 Percent In June Quarter

The consumers price index (CPI) rose 0.3 percent in the June 2014 quarter, Statistics New Zealand said today. This follows rises of 0.3 percent the March quarter and 0.1 percent in the December 2013 quarter. More>>

ALSO:

Half Empty: Dairy Product Prices Drop To Lowest Since December 2012

Dairy product prices fell to the lowest level since December 2012 in the latest GlobalDairyTrade auction, paced by whole milk powder and anhydrous milk fat. More>>

ALSO:

Get More From Scoop

 
 
Computer Power Plus

Standards New Zealand

Standards New Zealand
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news