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

 

Scoop Business: Alex Swney Pleads Guilty To $2.5M Fraud Charge

Alex Swney, former chief executive of the Auckland city centre business association Heart of the City, has pleaded guilty to dishonestly using documents to obtain $2.5 million. More>>

ALSO:

Petrol Burns Prices: Second Consecutive Quarterly Fall For CPI

The consumers price index (CPI) fell 0.3 percent in the March 2015 quarter, following a 0.2 percent fall in the December 2014 quarter, Statistics New Zealand said today. The last time the CPI showed two consecutive quarterly falls was in the December 1998 and March 1999 quarters. More>>

ALSO:

Scoop Business: NZ Broadcasters Launch Battle Against Global Mode ISPs

New Zealand broadcasters have confirmed they’ve launched legal proceedings against internet service providers who give customers’ access to “global mode”, which allows customers access to offshore online content, claiming it breaches the local content providers’ copyright. More>>

ALSO:

Sanford: Closure Of Christchurch Mussel Processing Plant Confirmed

The decision comes after a period of consultation with the 232 staff employed at the Riccarton site, who were told on 9 April that Sanford was considering the future of mussel processing in Christchurch. Recent weather patterns had impacted on natural spat (offspring) supply... More>>

ALSO:

Price Of Cheese: Dairy Product Prices Fall To The Lowest This Year

Dairy product prices fell in the latest GlobalDairyTrade auction, hitting the lowest level in the 2015 auctions so far, as prices for milk powder and butter slid amid concern about the outlook for commodities. More>>

ALSO:

Houston, We Have An Air Route: Air New Zealand To Fly Direct To The Heart Of Texas

Air New Zealand will fly its completely refitted Boeing 777-200 aircraft between Auckland and Houston up to five times a week opening up the state of Texas as well as popular nearby tourist states such as Louisiana and Florida. More>>

ALSO:

Scoop Business: Reserve Bank’s Spencer Calls On Govt To Rethink Housing Tax

The Reserve Bank has urged the government to take another look at a capital gains tax on investment in housing, allow increased high-density development and cut red tape for planning consents to address an over-heated Auckland property market. More>>

ALSO:

Get More From Scoop

 
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news