Monday, 23 January 2017

Set in stone

Fossilised Sunspots



The Economist reports on a study looking at tree rings in Permian fossilised trees and finding evidence of sunspot activity.

Articles on the Economist web site tend to disappear with time (unlike petrified tree rings) so I have uploaded it to the blog and you can read it below.


An ancient forest reveals the sun’s behaviour 290m years ago


The sunspot cycle was little different then from what it is now



EVERY 11 years or so, a new sunspot cycle begins. Sunspots are apparent blemishes in the sun’s photosphere, the layer which emits its light. Though still hot (about 3,500°C), they are cooler than their surroundings (about 5,500°C) and thus appear dark by contrast. A cycle starts with spots appearing at mid-latitudes in both northern and southern hemispheres. Over time, the spot-generating areas migrate towards the equator. As they do so, the amount of light and other radiation the sun emits first increases to a maximum and then decreases to a minimum, until the spots vanish and the cycle renews.

On Earth, the increased illumination of solar maxima drives photosynthesis, and thus plant growth. That permits botanists to use trees’ annual growth rings to work out what sunspot activity was like hundreds, and occasionally thousands, of years ago. Determining solar activity millions of years ago, though, has not been so easy. But it is of interest to solar physicists, who wonder how far back into the past the oscillations of the sun’s magnetic field that drive the cycle go, and how they might have changed over the course of time.

Now, Ludwig Luthardt and Ronny Rössler of the Natural History Museum of Chemnitz, in Germany, have cracked the problem. They have been able to apply the tree-ring method to petrified trunks from a nearby fossil forest. This forest (imagined in an artist’s impression above) was buried by a volcanic eruption 290m years ago, during the Permian period. And, as they report in Geology, Mr Luthardt and Dr Rössler have found that the sunspot cycle was little different then from what it is now.
The Chemnitz fossil trees, mostly conifers and ferns, are particularly well preserved. Volcanic minerals seeped into them soon after the eruption and petrified them before bacteria and fungi could rot their tissues away. Mr Luthardt and Dr Rössler selected 43 of the largest specimens and looked at their growth rings.

They found 1,917 rings which were in a good enough state to be measured under a microscope. They knew that the trees had died simultaneously, giving them a baseline to work from, and so were able to compare the rings from different plants. They were stunned by how clearly they could see the cycles.

About three-quarters of their specimens showed synchronous growth peaks like those caused by modern sunspot activity. In total, the rings they measured let them study 79 years of forest growth before the eruption. During this period, the solar cycle averaged 10.6 years. That compares with 11.2 years in the modern era, although this figure conceals wide variation in the lengths of individual cycles. Within statistical limits, then, it seems that the sunspot cycle was the same in the early Permian as it is now, suggesting that the sun’s magnetic oscillations were the same then as they are at present. Whether that is a coincidence has yet to be determined, but there is no reason why the method Mr Luthardt and Dr Rössler have developed should not be applied to other petrified forests, from different periods, to find out.

Assynt Geology

A North-West Highlands Geology Video


Bruce Buswell has brought THIS video to my attention. Its rather good! It promotes the North West Highlands Geopark.

Saturday, 21 January 2017

Next Week Monday 23rd to Sunday 29th January

NEXT WEEKS EVENTS

23rd January to 29th January 2017


The following is an extract from Bristol Geology CalendarMore details can be found in the Calendar and on the web sites of the relevant Society or organisation.



Monday



Tuesday



Wednesday

19:30
 Bristol Nats Geology AGM
WhenWed, 25 January, 19:30 – 21:00
WhereS H Reynolds lecture Theatre, Wills Memorial Building, University of Bristol, BS8 1RJ (map)
DescriptionThe Geology Section’s Annual General meeting will consider the report on Section activities during 2016 and appoint the officers and committee to serve for 2017. It will be followed by presentations or short talks by members of the Section. It is hoped that this will include an account of the findings from the recent excavation at Welton Hill near Paulton.

Thursday

19:30
 Dave Green's microscope course
WhenThu, 26 January, 19:30 – 21:30
WhereThe Chantry, Thornbury. (map)
DescriptionRocks and Minerals under the Microscope.  This 10 week course aims to introduce you to the identification and description of rocks and their component minerals under the petrological microscope. This is a practical course, each participant will be provided with a microscope and a set of thin sections of rocks, and will work through a course at their own pace. Held at The Chantry, Thornbury. First meeting 7.30 – 9.30, Thurs 12th January until March 23rd (not Thurs 16th Feb) in the Buckingham Room. Max. numbers 20, “first come, first served” due to number of slide sets. Cost £75

Friday



Saturday



Sunday

O.U. Geol Soc South West Branch Geoweekend and AGM - Field Trip
WhenSunday, 29 Jan 2017
WhereField-trip – location to be confirmed (map)
DescriptionField-trip – location to be confirmed, but plans are afoot to have a leader from Exeter University, Tremough Campus. (In case of bad weather, the field-trip may be shortened or cancelled) For more information contact Trevor by email: trevorlockwood25@gmail.com

Non Uniformitarianism in Geology and Politics

How Geology Won the Election for Trump


HERE is a very interesting YouTube video showing how geology gave the recent election to Donald Trump. And he gives a good account of various aspects of geology too! His YouTube channel looks quite interesting too!

I have a personal interest in this video because a picture he uses is MINE!!! At about 4 minutes 36 seconds is a picture of mine which has, with my permission, got onto Wikipaedia and which he makes good use of.

Banded Iron Formation, in Dales Gorge, Karajini National Park, Western Australia

Saturday, 14 January 2017

Next Week Monday 16th to Sunday 22nd January

NEXT WEEKS EVENTS

16th January to 22nd January 2017

The following is an extract from Bristol Geology Calendar

More details can be found in the Calendar and on the web sites of the relevant Society or organisation.

Monday

Teme Valley Geol Soc - Lecture
WhenMonday, 16 Jan 2017
WhereMartley Memorial Hall B4197 by Sports Ground (map)
DescriptionThe Anthropocene with Professor Ian Fairchild Contact Janet 01886 821061 Mem £1 Non £3

Tuesday

18:30
 Geological Society - Western Region
WhenTue, 17 January, 18:30 – 19:30
WhereTBC (map)
DescriptionRedcliffe Caves Tour

Wednesday



Thursday

19:30
 Dave Green's microscope course
WhenThu, 19 January, 19:30 – 21:30
WhereThe Chantry, Thornbury. (map)
DescriptionRocks and Minerals under the Microscope.  This 10 week course aims to introduce you to the identification and description of rocks and their component minerals under the petrological microscope. This is a practical course, each participant will be provided with a microscope and a set of thin sections of rocks, and will work through a course at their own pace. Held at The Chantry, Thornbury. First meeting 7.30 – 9.30, Thurs 12th January until March 23rd (not Thurs 16th Feb) in the Buckingham Room. Max. numbers 20, “first come, first served” due to number of slide sets. Cost £75


19:30
 Bath Geol Soc AGM
WhenThu, 19 January, 19:30 – 20:30
Where16 Queen Square, Bath (map)
DescriptionAnnual General Meeting 2017


19:30
 Thornbury Geology Group meeting
WhenThu, 19 January, 19:30 – 20:30
Description Thornbury Geology Group, The Chantry, Thornbury, 7.30pm, contact 01454 416882 The group is is an offshoot of Thornbury and District Museum and we welcome new members. Previous geological knowledge can be helpful but is not necessary as members are very willing to share their own knowledge with anyone keen to learn more about Earth Science. The group is loosely following a pre-recorded lecture series which is supplemented by use of other material and geological specimens. On occasions a guest speaker will talk on their specialist topic. Costs are met from attending members' monthly contributions and the group does not have membership subscriptions or a committee

Friday



Saturday

11:00
 South Wales Geologists' Association
WhenSat, 21 January, 11:00 – 12:00
WhereLectures at University of Wales Swansea are held in the department of Geography in the Wallace building. We meet on the landing area inside the main entrance to the building for refreshments with lectures in the main lecture theatre. (map)
DescriptionSaturday 21st January: (Swansea) Volcanic ash and rapid climate change, piecing together the past. Professor Siwan Davies (Swansea)

Sunday

Thursday, 12 January 2017

Early Scottish Fossil

Tetrapod Evolution

An informed source has told me of a very interesting, and well written, article in the Guardian about fossil finds in Scotland. You can find it HERE.


Aytonerpeton microps, also known as “Tiny”. A fossil from the Early Carboniferous of Scotland. The rock was CT scanned and the head printed at twice "life" size. It is still in the rock!

Tuesday, 10 January 2017

Courses by Dave Green

Dave Green's Programme


It can be a little difficult to navigate Dave's website so the following slipped my notice until it was brought to my attention. The original can be found HERE.

Contact details for Dave are:-
Email Dave Green, dave@geostudies.freeserve.co.uk 

Rocks and Minerals under the Microscope. 

This 10 week course aims to introduce you to the identification and description of rocks and their component minerals under the petrological microscope. This is a practical course, each participant will be provided with a microscope and a set of thin sections of rocks, and will work through a course at their own pace. Held at The Chantry, Thornbury. First meeting 7.30 – 9.30, Thurs 12th January until March 23rd (not Thurs 16th Feb) in the Buckingham Room. Max. numbers 20, “first come, first served” due to number of slide sets. Cost £75


Tuesday evenings in the summer: Field Course: Tues 6th June - Tues 18th July June 2017 Geology and Landscape in Gloucestershire (evening field course Tuesdays 7-9 First meeting point:- Haresfield Beacon: Meet at the roadside pull-in just before the steep descent towards Haresfield village GR SO 824 090 . Further sessions on website, separate leaflet, and/or by contacting Dave Green.


Field Course February 2017 : probably a bit late for this but.... 
The Geology of Northern Sardinia Dates will be for a week to 10 days trip around a period from Fri 10th to Monday 20th . The two terranes making up Sardinia were separate parts of Gondwana during most of the Palaeozoic. They participated in the continental collisions at the start and end of the Carboniferous to produce the Variscan Orogenic Belt, across which it provides a classic cross-section showing different styles of folding and faulting, and different grades of metamorphism, together with the intrusion of vast volumes of granite. Following a long period of erosion it became a carbonate shelf environment during the Jurassic and Cretaceous. During the Tertiary and Quaternary, subduction of Tethys oceanic crust produced extensive volcanic activity. LET ME KNOW BEFORE CHRISTMAS IF YOU WANT TO COME to take advantage of cheaper air fares 

The Geology of the Oceans past and present (including plate tectonics, environments, and current/developing ideas on oceanography and marine geology). Often termed the last frontier to be explored on Earth, there have been great advances in our understanding of the oceanic realm over the past half century. This course aims to study the main developments and what we might expect in the future, based on current research. Monday 24th April, for 10 weeks, until 10th July (not 1st nor 29th May). Held at Wynstones School, Stroud Road, Whaddon, Gloucester from 7.30-9.30pm on Mondays. Cost £70.