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Reptile Fossils from an Unexplored Valley.

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The first barrier to accessing Mangahouanga Stream Three years ago I visited Mangahouanga Stream in Hawkes Bay  along with a group of GNS Scientists. This is the area where Joan Wiffen, New Zealand’s famous “Dragon Lady” found the only known bones of dinosaurs from New Zealand, as well as various marine reptiles, prior to her retirement from fieldwork about ten years ago. I described this visit in my blog at the time. What I didn’t mention in my blog was the existence of a remote valley that we believe might have only been visited once by a geologist prior to 2009.  The valley is a tributary of the Mangahouanga Stream. Pete Shaw with marine reptile bones from Wiffen Valley As well as being protected behind a large privately owned forestry block, this hidden valley is made particularly inaccessible by a high waterfall and densely forested ridge. Along with the forest manager Pete Shaw, I had managed to enter the valley via very steep and rugged bush in 2009. We spent several unforgettable hours travelling down the un-named stream (now called Wiffen Stream), finding several Cretaceous reptile bones in large concretions. The photo shows Pete in 2009 with the prize find of the day moments after he pulled it out of the stream. It is a cluster of several reptile vertebrae, subsequently identified as belonging to an elasmosaur. Although heavy, Pete managed to carry it out, whereas most of the fossils we found that day had to be left in place. Last week I returned to the area with a team of GNS palaeontologists along with Victoria University student Ben Hines. One of our aims was to explore the hidden Wiffen Valley to  have a closer look at its geology and fossils, This photo shows GNS palaeontologists James Crampton and John Simes in the upper section of Wiffen Stream. There were log jams, tree trunks and waterfalls to negotiate as we travelled down the stream. We took our time to throughly check out the boulders for fossils as we moved slowly along. The reptile bones are typically found in very hard concretions like this one. We were unable to identify this particular bone, or remove it from the concretion, so it was left in situ along with several others that we saw. In this photo  Marianna Terezow of GNS Science can be seen tackling the dense bush that must be traversed to access and return from the hidden valley.

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Moa Hunting

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Takaka limestone country Whilst on holiday in the Nelson area last week, I went for a look around the limestone plateau of Takaka Hill, not far from the huge natural shaft of Harwood’s Hole. I managed to persuade a couple of friends to come along for the adventure. The area is very rugged, covered with rock outcrops and tangled vegetation. There are many caves (see my earlier blog post from January 2010) and my particular interest was to look for small vertical shafts that might have acted as lethal traps to the moa that once roamed the area. The delights of moa hunting With some careful searching, it did not take long to find some cave entrances. Some of the shafts are very deep and obviously care is needed in this environment to avoid the fate of becoming entombed and fossilised just like the moa that we were hoping to discover. As you can see, some of these caves are very small. With a bit of wiggling and squirming, we were able to push down into them. Moa bones lie scattered at the bottom of a cave Sure enough, a couple of them contained parts of moa skeletons lying at the bottom. In this image you can see a variety of bones, including leg bones and a pelvis. The number of different bones that we saw in this cave indicated that at least three or four moa individuals had been caught there. Moa pelvis  This is a close up of the pelvic bones of a moa Moa bones in narrow fissure At the very bottom of this cave, there were more bones visible, but the fissure was too tight to get close to. We were very satisfied with our discoveries, and happy to leave the bones in place for future rediscovery and study.

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Groundwater dating around Lake Rotorua

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“If you want to have an insight into a society, just look at the water in the streams and rivers” Uwe Morgenstern, GNS Science’s specialist in groundwater and ice dating, runs a laboratory that is the most accurate water dating facility in the world. His methods are so precise, that they are four times more accurate than the next best lab, out of a total of about 70 such laboratories worldwide. In a nutshell, groundwater dating works like this: Cosmic rays from outer space interact with our atmosphere and form very small amounts of tritium, a radioactive hydrogen isotope with a half life of 12.3 years. This cosmogenic tritium eventually becomes part of the atmospheric water, with one normal hydrogen atom replaced by a tritium atom. As this water (or snow) precipitates and becomes incorporated into groundwater, it is no longer interacting with the atmospheric tritium, and its tritium concentration starts to deplete due to radioactive decay. Measurement of tritium concentrations in groundwater allows the time since it fell from the sky to be calculated, back to a maximum age of about 100 years. Over the last few days I have been out in the field with Uwe and Mike Toews (a groundwater modeller at GNS Science) sampling the streams and springs around Lake Rotorua. The water quality in Lake Rotorua, and the many other smaller lakes in the area, is very important to the local community, for drinking, agriculture, recreation and tourism, including world famous trout fishing. Farming, especially dairy, beef and sheep farming, is also a very important activity around the region. Farm effluent and fertilisers cause nutrients, particularly nitrates, to enter the groundwater and eventually get transported into the lake. As a result the chemical balance changes, with potential negative impacts such as the growth of toxic algal blooms and other ecological changes such as impacts on fish. To understand the effects of land use on the water quality in the ground, in streams, rivers, and lakes, you need to not only  monitor the concentration of pollutants in the water, but also measure the age of the groundwater. For this reason, Uwe has been studying the groundwater around Lake Rotorua for a number of years. With such large groundwater systems, it can take many years or decades for polluted water (for example nitrate from farms) to reappear back on the surface in streams and lakes. Because of this time lag, large groundwater systems can silently become contaminated until the contaminated water reaches the spring discharge. Then it will also take the same long time to flush the contaminated water out of the groundwater system. The data Uwe is coming up with shows a range of time spans for the input of  lake water, from very quick (months) to over a hundred years in the case of Hamurana Spring. The map shows coloured dots representing the springs and streams that were on our list for resampling. For a news article about the findings of this research have a look here. Here is a video, describing the research and the findings so far:

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“Drop, cover and hold on” is the best advice…

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How to Respond to an Earthquake in New Zealand This article has been compiled by Karen Hayes at GNS Science with the help of experts including Julia Becker and David Johnston from the Joint Centre for Disaster Research at Massey University, and Adrian Prowse from the Ministry of Civil Defence and Emergency Management (now the National Emergency Management Authority). All photos are by Julian Thomson.  Information about the ‘Triangle of Life’ has been disseminated via a chain e-mail that has been in circulation since the 1990’s. The claims regarding the “Triangle of Life” earthquake response are widely discounted. The “Triangle of Life” is not an advocated approach to responding to earthquakes and has been internationally dispelled as being unsound practice. In modern countries such as New Zealand, most buildings are constructed well and you are more at risk of getting hurt from objects flying around rooms. Therefore people should “drop, cover and hold on” in an earthquake. The New Zealand Ministry of Civil Defence and Emergency Management includes the recommended “drop, cover and hold on” advice on their webpage that you can download:  I recommend you print the fact sheet and stick it on your fridge to remind yourself and your family of how best to respond in an earthquake.    Let’s just take a quick moment to consider one of the claims in the “Triangle of Life” chain e-mail. It states that children have been killed in past earthquakes because they were under their school desks and these were flattened when the building collapsed. It states that they would have been safe had they been lying beside the desk, instead of under it, where a supposed ‘void space’ should be. Realistically speaking, if the desk was not substantial enough to protect the child under it and was flattened by the collapse of a building, then any void space wouldn’t have been large enough to protect the child lying on the floor next to it either. A child is better off getting under the desk to prevent them from being struck by falling items. In the Christchurch earthquake on 22 February 2011, when children did “drop, cover and hold on” under desks, there were no significant injuries reported from any school in the Christchurch area. Building codes designed to reduce earthquake risk will ensure that buildings are unlikely to collapse in the first place. Why Rescuers and Experts Recommend Drop, Cover, and Hold On (the following is taken directly from the earthquakecountry website) Trying to move during shaking puts you at risk: Earthquakes occur without warning and may be so violent that you cannot run or crawl; you therefore will most likely be knocked to the ground where you happen to be. On that basis, it is best to drop before the earthquake drops you, and find nearby shelter or use your arms and hands to protect your head and neck. “Drop, cover, and hold on” gives you the best overall chance of quickly protecting yourself during an earthquake… even during quakes that cause furniture to move about rooms and even in buildings that might ultimately collapse. The greatest danger is from falling and flying objects: Studies of injuries and deaths caused by earthquakes over the last several decades show that you are much more likely to be injured by falling or flying objects (TVs, lamps, glass, bookcases, falling masonry, etc) than to die in a collapsed building. “Drop, cover, and hold on” (as described above) will protect you from most of these injuries. If there is no furniture nearby, you can still reduce the chance of injury from falling objects by getting down next to an interior wall and covering your head and neck with your arms (exterior walls are more likely to collapse and have windows that may break). If you are in bed, the best thing is to stay there and cover your head with a pillow. Studies of injuries in earthquakes show that people who moved from their beds would not have been injured had they remained in bed. You can also reduce your chance of injury or damage to your belongings by securing them in the first place. Secure top heavy furniture to walls with flexible straps. Use earthquake putty or velcro fasteners for objects on tables, shelves, or other furniture. Install safety latches on cabinets to keep them closed.   Building collapse is less of a danger: While images of collapsed structures in earthquakes around the world are frightening and get the most media attention, most buildings do not collapse at all and few collapse completely. In earthquake-prone areas of New Zealand, as in many other countries, strict building codes have worked to greatly reduce the potential of structure collapse. However, there is the possibility of structural failure in certain building types, especially unreinforced masonry (brick buildings) and in certain structures constructed before the latest building codes. Rescue professionals are trained to understand how these structures collapse in order to identify potential locations of survivors within “survivable void spaces”. The main goal of “drop, cover, and hold on” is to protect you from falling and flying debris and other non-structural hazards, and to increase the chance of your ending up in a “survivable void space” if the building actually collapses. The space under a sturdy table or desk is likely to remain even if the building collapses – pictures from around the world show tables and desks standing with rubble all around them and even holding up floors that have collapsed. Experienced rescuers agree that successfully predicting other safe locations in advance is nearly impossible as where these voids will be depends on the direction of the shaking and many other factors. If you receive the email in future…If you receive the “Triangle of Life” email, you should reply to the sender and let them know the advice is wrong, and point them in the direction of correct information about how and why to “drop cover and hold on”! Summary:     Do: • Identify safe places at home and

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Te Mata Peak

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Last week, following my visit to Castlepoint I also headed further north to Hawkes Bay. State Highway 2 runs parallel to the central North Island mountain ranges, which had just received fresh snow from a recent southerly blast, to provide a classic New Zealand pastoral scene… Te Mata Peak near Havelock North is a popular spot for runners, hikers and paragliders. On a clear day there are  spectacular views across the landscape from the coast all the way to the volcanic peaks of Ruapehu in the centre of the North Island. The buttresses of Te Mata Peak are made of Awapapa Limestone. This formation, which is about three and a half million years old, is also found to underly other nearby coastal hills in the Hawkes Bay area. It was formed along a string of offshore shallow water shoals and tidal banks. At that time the coastline was about 40 kilometres to the west, along the present edge of the central mountain ranges. In between, the sediments of the same age are mudstones that represent much deeper water than the Awapapa limestone. Armed with my Kiwi Fossil Hunter’s Guide, I located a way to climb down on the eastern side of the peak to have a close up look at the cliff section just north of a radio mast, a few hundred metres down from the summit car park.  Although there isn’t a wide variety of fossils in these rocks, there were some vary well preserved specimens such as these examples of a scallop called Phialopecten marwicki, as well as barnacles, oysters, brachiopods (lamp shells) and coral-like bryozoans. In places, thinly bedded layers of shell fragments show that water currents were strong, indicating shallow water conditions when the limestone was deposited. Careful research by scientists has found that the alternating bands of hard, strongly cemented grey limestone and softer, orange sandy layers represent cycles of sea level change during the Pliocene Epoch. The harder layers formed because at shallower depths there were more water currents, which allowed more calcium carbonate rich water to flow through the sediments. This would have been during the ice ages, when huge amounts of sea water were locked up in polar ice caps, thus lowering the sea level. The warm period (interglacial) deposits have less carbonate cement to strengthen them and are therefore etched out more easily by erosion. These deeper water sediments are now underneath overhangs of the harder layers. The example here had clusters of large oyster shells scattered within it.

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Castlepoint and the Kiwi Fossil Hunter’s Handbook

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James Crampton and Marianna Terezow’s The Kiwi Fossil Hunter’s Handbook won the LIANZA Elsie Locke Award in the  non fiction category. With James away from town, Marianna attended the awards ceremony last night to accept the prize. Here you can see clearly that Marianna was one of the people behind the book! Armed with the fossil hunter’s guide, I recently went to visit a couple of the localities described within it. The first was Castlepoint, a popular spot on the Wairarapa coast of the North Island. It is a dramatic rocky promontary, enclosing a lagoon and extending out to sea. Just to the south is a steep track leading up to the top of high cliffs overlooking the bay. The spectacular coastline is a favourite spot for fishing and hiking as well as exploring for fossils. The Castlepoint Reef is jam packed with fossil fragments, indicating that it was created under the sea and has since been uplifted. The fossils have been dated at about 2.4 million years old. Because of fault lines on either side of the reef, nearby older and softer strata have been uplifted even more, and then eroded away, leaving the hard limestone of the reef to stand proud of the surroundings. The seaward side of the reef is a dramatic cliff, that would be easy to fall off if you weren’t careful. From studying structures such as slumped (buckled) beds and mixed rock fragments within the reef, geologists think that it represents the debris that accumulated in a steep sided canyon. Material occasionally avalanched down into the depths from above, mixing up fossil fragments and rocks into the sedimentary sequence. Here you can see an example of these disturbed beds, with a scattering of white fossil shells included. In this photo you can see that much of the reef is made up of densely packed shell fragments ( in this case clams and barnacles) that are piled up on top of each other. This univalve is similar to some that are found today on many New Zealand beaches. Both cold water and warm water fossil shell species can be found in the Castlepoint reef . It is thought that at least two ice age cycles are represented in the rocks, each lasting about 40 000 years. The fossils assemblages at Castlepoint show a mixture of deeper water species that would have lived several tens of metres below the surface in the bottom of the canyon, and shallower types that were washed down from the sea floor alongside. These brachiopods called Neothyris campbellica are about 5 cms long. They were filter feeders that attached themselves to the sea floor with a stalk. An early morning view of Castlepoint lighthouse with the Castle in the distance across Deliverance Cove.

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Where was that earthquake and how big was it?

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We have a new GNS Science video today that explains how scientists locate the source of an earthquake and then calculate the magnitude. John Ristau, from GNS Science’s GeoNet programme talks through the steps of the process… And in case you missed this earlier video, here is Matt Gerstenberger, describing how earthquake forecasts are made using statistics derived from global aftershock sequences:

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Christchurch Quake Q&As

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Kelvin Berryman (Image: Stuff.co.nz) The following questions were posted by a Christchurch resident on our GNS Science Facebook page. I think they are good questions which will be of interest to many people in the quake affected area.  I have re- posted them here, along with answers provided by Kelvin Berryman, a leading earthquake scientist at GNS Science, and manager of the Natural Hazards Research Platform. Kelvin was awarded the Queen’s Service Order in the 2011 Queen’s Birthday Honours recently for his services to science.  Request on behalf of everyone who lives in Christchurch, we are all so afraid and re-thinking our futures – it would be good if some questions could be answered in plain English for us: 1. Are you aware of ALL the major fault lines in Canterbury – Yes I think the research community knows where the MAJOR faults are. However, the current Canterbury earthquakes are being generated by some quite moderate-sized faults – they are buried beneath many 100’s of metres of gravels or the several million year old volcanic rocks of Banks Pensinsula. We cannot see all of this size of fault. Liquefaction volcanoes dot the beach, June 2011  2. Which faults are the biggest risk for large earthquakes? The faults that are being strained the hardest have the highest chance of producing large earthquakes. In the South Island these are the Alpine, Hope (through Hanmer to Kaikoura), Porters Pass (look to the right the next time you drive over Porter’s Pass toward the West Coast to see the fault line crossing the hillsides), and further north into Marlborough. Unfortunately all faults that are being strained have to break some time, and this is what is happening around Christchurch at present. These are very rare events for Canterbury, although I realise completely this scientific understanding provides no solace for the people who have lost so much.  Ready to topple… Port Hills boulder 3. What are the future implications, area by area e.g. which are the safest areas to live in? In Canterbury the safest areas are probably those farthest from current earthquake activity, and to the west away from the liquefaction susceptible areas are better. In New Zealand areas north and west of New Plymouth and Hamilton have a lot fewer earthquakes than other parts of the country. But remember that other natural hazards like floods, and tsunami have different likelihoods in different parts of New Zealand. 4. What % risk is there of a tsunami – I do understand that there are many faults on our coast line, how sure are you that there is no tsunami risk, vertical or horizontal, and why?  Rockfall at Redcliffs RSA Canterbury does have a risk of tsunami but the principal source is huge earthquakes occurring in South America, and it takes roughly 12 hours for the tsunami to arrive, so there is plenty of time to be safe. The fault lines offshore of Canterbury are small and not capable of producing a major tsunami, but if you are on the beach when you feel a big earthquake and the shaking goes on for 20 seconds or more then it is important to get several metres above the beach. Go quickly walking, perhaps drive if practical, but watch out for being stuck in a traffic jam at low elevation when simply walking or running for 50-100m is all you need to do. If you live near the coast join a local group, obtain readily available information on self evacuation planning, and make a community plan. The local civil defence officer will help you.  Extreme Shaking 5. Are you – (scientists/geologists in Christchurch) afraid when an aftershock hits, if you shared exactly your feelings thoughts on this issue it could give us all some peace on the subject. To be honest I think the residents of Canterbury have now have more experience of earthquakes than most earthquake scientists.  I think most people whether they are scientists or not are apprehensive when an earthquake starts and will often be afraid too. Perhaps we have the advantage of trying to remember our scientific training when in those few seconds we are thinking about how big will it be. I am sure now that with your experience you know that the really big and damaging earthquakes hit so hard that you are thrown down or find it difficult to move. Fortunately these ones are much less common than the smaller but nevertheless worrying ones.                                 ~          ~          ~          ~ For more geoscientist’s answers about the Christchurch Earthquakes, have a look at the ‘Ask an Expert’ page published earlier this week in the Christchurch Press.

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The White Terraces Reappear after 125 years

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On 10th June 1886, exactly 125 years ago today, Mount Tarawera erupted briefly and violently, resulting in the disappearance of the Pink and White Terraces of Rotomahana, and devastation of the landscape. The former lake disappeared and was slowly replaced by the much larger and deeper lake which remains to this day. This 1880 Charles Spencer image is  courtesy of Te Papa Museum Last January, in a GNS Science led international expedition, Cornel de Ronde and his team rediscovered the Pink Terraces at the bottom of the  modern lake, which had been so drastically altered and deepened by the eruption. The Pink Terraces were first spotted in images from a side-scan sonar that was mounted in an autonomous underwater vehicle (AUV) used to survey the lake. Today Cornel de Ronde announced that the White Terraces have also been found using data retrieved on the last day of the expedition, that had not been analysed until recently. When the Pink Terrace side-scans were first seen, they were nothing like anything that had been observed by the team before. An underwater camera was used to confirm that they did indeed represent the Pink Terraces. (For details of the Pink Terrace discovery watch this video). Similar looking side scan images have now been found in the location where the White Terraces are expected to have once existed. A horizontal segment of the formations over 150 metres across may be the remains of the silica terraces along the former shoreline of the lake, now tens of metres below water level. It is not yet known whether more of the terraces lie hidden beneath volcanic mud, or whether the rest of them were forever destroyed in 1886. Future exploration may settle this question. Ron Keam of Auckland University is an expert on the history of the Tarawera Eruption and the Rotomahana landscape. He compiled this map of the former Lake Rotomahana as accurately as possible by detailed study of  pre 1886 photographs. The Pink Terraces can be seen on the left (west) side of the lake, with the White Terraces at the top (northern) end, about a kilometre northeast of the Pinks. The image to the right is the compiled side scan of the part of the modern lake under which the remains of the terraces lie.  The long straight lines show the path of the AUV as it progressed up and down the lake area.  The red circles show the locations of the two sets of terraces, about 1 kilometre apart. Lower left are the Pinks and upper right are the newly refound parts of White Terraces. This close up of the side scan image  shows the curved overlapping terrace formation on the lower half below the blank, unscanned area. These features are very similar in general appearance to the photographically verified scans of the Pink Terraces found last summer. (All sidescan images courtesy of our US project partners at the Woods Hole Oceanographic Institution) For more details have a look at our media release, and watch the video of Cornel de Ronde describing how the discovery unfolded step by step, including the crucial hook shaped landform that first led to the location of the Pink Terraces, followed now by the Whites:

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