by Bill Dailey
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We were lucky enough to take a
once-in-a-lifetime family trip to New
Zealand for about two weeks in October 2004. During that time I was
able to spend a day searching and collecting material at several of the
classic Oamaru diatomite localities. Oamaru diatomite was laid down
during the Late Eocene period about 35 million years ago, and contains
the most exotic marine forms of any in the world. I used the 1961
articles by Doig published in the journal The Microscope, and the 1991
monograph "The Oamaru Diatomite" edited by Edwards and published by the
New Zealand Geological Society as Paleontological Bulletin 64 to guide
the search. I was also lucky enough to get some great help and advice
from a couple local landowners, Bob Allan and Ross Mitchell. Here's a map
showing the locations of some
historic diatomite sites ,
taken from the Doig article. I was able
to visit a number of the localities listed on the map, and most are
last updated 6/9/11
Located on the farm of Nancy and Bob Allan, this deposit is located in the center of a sheep field about a 3 minute walk from the house. The diatomite is off-white and soft. Cleaned material has a wide variety of forms in a good state of preservation. However the yield of cleaned material is low (maybe 2%) compared to the amount of starting diatomite. The sheep have been chewing on the diatomite!
Here's a picture of the Dailey women with Nancy and Bob Allan. We had a great lunch!
This is a steep hillside located on east side of Springhill Road. It is used as a cow pasture. The diatomite occurs through most of the hillside but the top of the hill is capped with 20 feet of limestone. The deposit starts on the right side of the picture and runs another 100 meters or more past the left side of the picture. The picture is a panorama stitched together from three separate pictures. The hillside is much steeper than it appears in this picture. Click on the picture to get a BIG one. The two figures are my daughters dutifully hunting for diatomite for their father.
Here's a picture of me collecting on the hillside about one third of the way down the hill. Notice how steep it is. You can just see Williams Bluff in the distance. The diatomite is located on most of the hillside.
Here's a couple pictures of the diatomite that was collected from the hill. This is Jackson #3 and Jackson #4 samples.
This location is a long ride from the main road in a four wheel drive vehicle. It's part of an extensive sheep grazing field complex. The hill is pretty steep but not as steep as Jackson's Paddock. Doig reports two bands of diatomite (his a--a and b bands) while Edwards reports 3 layers. Doig reports that the Forrester's Upper material is the best of the Oamaru diatomites, while Edwards reports that Forrester's Lower is in a better state of preservation.
In the ground, the diatomite looks like parts of the Jackson's Paddock material. Here's a picture of the "Forrester's Lower" material collected from the hill
This is a dangerous place to collect because it is so steep and rocky. I was honestly concerned that I would slip down the face of the cliff! I can understand why so few samples from this location are found in the literature. This is a picture of Williams Bluff taken from the top of Jackson's Paddock. We collected samples at the point near the top of the cliff.
Here are pictures looking up and then down the slope of William's Bluff from one of the collecting sites. It's a long way to the bottom!
Here's an image looking up from the road. We collected samples to the right of the fence line and just above the main group of trees.
And here's a picture of one of the collecting sites (Williams Boulder) along with Ross Mitchell. Ross very kindly took me to several of the diatomite locations.
Here's a closeup of the diatomite under the boulder.
Here's a view from the top of William's Bluff looking southeast. The Pacific Ocean is in the distance.
This location is accessed by four wheel drive vehicle. We were not able to locate the material mentioned by Doig and the Paleontological Bulletin. However there had been a new road cut with a bulldozer just across the gully, and diatomite was found here. However this material is difficult to clean and the forms are mostly broken and not well preserved. Troublesome gully is located straight ahead over the hill and across the gully.
This location is more overgrown with conifers than 40 years ago, but is still substantially the same as described by Doig and Edwards. I did not manage to visit this location because of time constraints but Lionel Chew and his wife April did collect material for me here in 2003. He took a couple pictures of the area to illustrate.
Here is location #2 according to Edwards
Here is location #3 (disregard the black arrow pointing to the stone fence).
Very close to Bain's and
in the middle of a field under a large boulder lies a collecting site
known as Totara. Bruce Comfort and his wife Joyce were able to collect
material for me from this site in 2010. The material is similar, but
slightly different, to that of Bains.
Here's a picture of Bruce in front of Totara.
Cormack's was located in the banks of the rail line situated in front of the old Taylor Limeworks. Unfortunately about 10 years ago the railroad track and timbers were removed and the area bulldozed to smooth it out even with the main road. This removed or covered the diatomite, and there are no longer any outcrops visible. This is really unfortunate since this was excellent diatomite. It was easily gathered since the outcrop was very obvious and close to the main road. I suspect that if one digs here they could locate some of the diatomite again. However we did not have time for such fun.
While I didn't get a chance to visit this locality, the Hastings are mining the diatomite and selling it as Kitty Litter. This diatomite is the hardest of all the Oamaru samples, almost like rock.