Wednesday 29 September 2010

Free British Regional Geology Survey 1948 books

GreenSpirit Books & Schumacher Book Service of Warminster have 18 issues of the British Regional Geology Survey 1948 for disposal, gratis. The areas covered are:
Pennines & Adjacent Areas
Welsh Borderland
South-West England
Midland Valley, Scotland
Central England District
Scotland Tertiary Volcanic Districts
East Anglia
East Yorks & Lincs
North Wales
South of Scotland
Wealden District
Bristol & Gloucester
Scotland: Northern Highlands
Grampian Highlands
Hampshire Basin
London & Thames Valley
Northern England
South Wales.
Contact details are on the website

Monday 27 September 2010

Sad news

Ron Pickford died peacefully in his sleep on the 18th of September. He was almost 90.
Among his many achievements, Ron was largely responsible for saving the BRLSI collections. Click here for some background.
The photo shows Ron with Bev Halstead. Ron was the first recipient of the Halstead Medal from the Geologists' Association.

Sunday 26 September 2010

New Guide - Vale of Wardour - October 9th

On Saturday October 9th at 2pm there is going to be a field excursion to celebrate the publication of the Wiltshire Geology Group's latest Earth Heritage Guide: Explore the Geology and Landscape of the Vale of Wardour.
Meet at 2.00 p.m. Tisbury Tithe Barn (Grid ref. ST 952 292), DPAS car park. Walk along footpaths for about 3/4 mile to Chicksgrove Quarry to see newly exposed top Portland/early Purbeck algal 'reefs', with huge bivalves & fossil wood.
We will then go to Fovant to look at the Upper Greensand both in buildings and in situ.
Arrive Fir Hill about 4.45pm; walk up to viewpoint at the top of the Greensand (park at entrance to wood) look at shell bed at top of building stone then walk through Fovant looking at Greensand & Chilmark stone buildings.
Further details from WWG website.

Friday 24 September 2010

Kirtlington Quarry - October 3rd

Public Open Afternoon at Kirtlington Quarry from 1 – 5pm.
Situated down Mill Lane opposite Kirtlington village green & pond. GR SP 494198.
Many fossils have been found here including bones & teeth from dinosaurs, flying reptiles (pterosaurs), sharks & crocodiles. However, the site is world famous for its Middle Jurassic mammal fossils.There is plenty of opportunity to find some of your own Jurassic fossils at Kirtlington as many of the loose rocks at the quarry faces contain lots of fossil shells and fragments of shells.
OGT executive members & young volunteers from the Wychwood V-project will be on hand to explain the geology and industrial history of this important site.Volunteers from the local conservation society, KWACS, will be leading wildlife trails around the quarry. No need to book. We will have a small stand at the event & will be providing hot refreshments.
Further details from Oxford Geology Trust

Tuesday 21 September 2010

Biblical parting of the Red Sea could have happened

One of the most dramatic episodes in the Old Testament, the parting of the Red Sea, may have happened. Click here for more details. A new computer modelling study suggests a powerful wind could have divided the waters just as depicted in the Book of Exodus.

Wednesday 15 September 2010

September events in Oxfordshire

Events organised by the Oxfordshire Geology Trust.
Saturday, 18th September ­ Fossil Hunting trip to Northcot Brickworks near Blockley in Gloucestershire. This quarry is well-known for its abundant fossils, so do consider coming along.
Saturday, 25th September ­ Practical clearance session at Kirtlington Quarry in Oxfordshire in preparation for the public open afternoon we are running on Sunday, 3rd October. This quarry is famous for its mammal, reptile, fish and amphibian fossils. 'Hands-on' sessions are always good fun.
Further details and booking on the website.

Thursday 9 September 2010

Conservation of the Geological Display area at Bradford on Avon

Sunday October 3rd at 10am
Meet at the tea shop by the lock on the Kennet & Avon Canal at Bradford on Avon.
Please bring gloves and hand tools, including brooms.
All volunteers welcome.

Monday 6 September 2010

A plea for rock thin-section makers

Is there anyone out there who is actively making thin sections or using them regularly? I am an amateur with a 1.5 decades field tripping background, who collected rocks and began making sections some five years ago. I have collected parts of Leitz and Vickers Pol microscopes to build my own for observation and photography and have all the Atlases but I don't have any contacts in the West Country who are into any of this.
I believe that declining interest in amateur petrology has seen not only the end of the Association of Thin Section Makers but UK suppliers of decent machines within the reach of amateurs. I'm lucky to have found post war UK kit and have updated it to work well.
If there is anyone with a matching interest, please contact me, either by email or by posting a comment on this blog.

Yellowstone Hot Spot shreds ancient Pacific Ocean

If you thought the geysers and overblown threat of a supervolcanic eruption in Yellowstone National Park were dramatic, read on: deep beneath Earth's surface, the hot spot that feeds the park has torn an entire tectonic plate in half.
The revelation comes from a new study in the journal Geophysical Research Letters that peered into the mantle beneath the Pacific Northwest to see what happens when ancient ocean crust from the Pacific Ocean runs headlong into a churning plume of ultra-hot mantle material.
Geologically speaking, the Pacific Northwest is a peculiar place. Hot spots usually sit way out on their own in the middle of a tectonic plate (think Hawaii or the Galapagos). Not Yellowstone -- it pokes its way to the surface just a few hundred miles from the edge of the North America plate, where a giant trench sends the Juan de Fuca tectonic plate sliding underneath Washington, Oregon, and northern California. Peering into the middle of this tectonic traffic jam is a tricky business. So scientists, led by Mathias Obrebski of the University of California, Berkeley, had to build an image from seismic waves bouncing around inside the mantle. What they found was a subterranean world filled with violence.
The original data figures are a little hard to look at, but the team built a cartoon representation of what they think is going on down there. Around 19 million years ago, the Yellowstone hot spot first ascended from deep within the mantle. As it neared the surface, it ran into the subducting Juan de Fuca plate. But the Juan de Fuca plate was itself young at the time (there's a mid-ocean ridge just off the coast of Oregon that forms brand new crust to this day), so it hadn't had the chance to fully harden yet. When the crust and hot spot met, the hot mantle plume found a weakness in the plate -- perhaps a pre-existing fracture -- and punched a giant hole through it.
So, who cares? The encounter has had several amazing consequences:-
First, and most obvious, it resurfaced much of northern Nevada, Idaho, and Wyoming over the last several million years in basalt through a series of massive volcanic eruptions. Then there were the tremendous supervolcanic explosions, which coated much of the western U.S. in thick blankets of ash and made the Yellowstone park region what it is today.
Second, the team points out that the rise of the Yellowstone plume also coincided with a large change in the rate at which the crust of the Pacific Ocean dives beneath North America. It's possible that the shattered underlying plate simply didn't pull as much weight anymore, and the subduction zone slowed down.
It's a new chapter in what we know about Yellowstone's legendary power to change the landscape. Not only did its massive eruptions coat North America in ash from Idaho to the Mississippi River, and south almost to the Gulf of Mexico, but its deep plume sent a ripple effect through the very roots of the continent and the Pacific Ocean that fundamentally altered the coastline of the Pacific Northwest.
Thanks to Bernard for this interesting article.