Planet Earth - The Cryogenian Period or Snowball Earth

Apologies for the delay in rebooting the Whatlington and Vinehall Street Archive,this posting describes a period when the planet's surface was covered in snow and ice is written at the same time the village has entered a period when the snow and ice has covered much of the Whatlington and Vinehall Street. 

The Cryogenian period combines the two Greek words for both "ice" and "birth" and it suggests that this period that ran from 850 to 630 million years ago. Within these 220 million years, the Earth had to deal with two glacial periods - the Sturtian and the Marinoan - where the glacial work extended to the the equator.

It is possible to record the work of erosion by ice (glacial erosion) by studying the palaeo-landscape and the debris left by the glacial retreat (the warmer climate melts the ice). These deposits have been found in Australia, China, Congo, Ireland, North America, Norway, the Sahara desert and Scotland.

The Sturtian glacial period is estimated to have run from 750 to 700 million years ago, whereas the Marinoan (also known as the Varanger - named after the Norwegian fjord where tillite (glacial deposit) was found by Reusch in 1891) ended in ??

There are several mdoels or hypotheses that suggest the potential process or cause for the initial conditions for the model of Snowball Earth (they can be found here of which I have summarised below):

Williams (1975) proposed that the angle of the Earth's orbit was greater than the present angle; if the angle were greater than 54 degrees, the energy from the sun would heat the polar regions more than the equator and potentially allow glaciers to form around the equator. The Milankovitch cycle, named after a Serbian civil engineer and mathematician, suggests that a global wobble of a few degrees over a period of tens of thousands, but not tens of degrees. A study of stromatolites (remember those?) in the 1980's suggest that the angle of the Earth to the sun was within its present limits.

Another model suggested that the sun's heat was less than today due to the maturation of the sun, this may have led to the planet more susceptible to global freezing and despite an early glacial period, the Huronian glaciation in the Siderian Period, it does not suggest why more glacial periods did not occur previously.

There are more three more theories that range from a change in the sea levels that affected the global energy budget; the global location of the continents around the equatorial region that led to a change in the carbon dioxide levels in the atmosphere; even the break up of the supercontinent Rodinia may have led to Snowball Earth.

Equally, there are a similar number of theories that led to the melting of the two glacial periods and these can be found here.

Planet Earth - The Neoproterozoic Era - The Tonian Period

The Neoproterozoic Era (1,000 to 542 million years ago) is the third era that makes up the Proterozoic Eon and this era is made up of three periods - the Tonian, Cryogenian (I bet this one is a bit cold) and the Ediacaran. It should be said that little is known about this era, although scientists are starting to find more about it, especially the third period of it (the Ediacaran). 

For this posting, I shall focus on the Tonian period (the period of 1,000 to 850 million years ago). Despite his presence in the early 21st Century politics, this period was not named after Tony Blair; the word derives from the Greek word "tonas" meaning "stretch". 

During this period, it is thought that the supercontinent, Rodinia, started to break up

I haven't mentioned this before, and it should be a good idea to mention them despite the fact they have been around since 3,200 million years ago. The acritarchs are small organic fossils (normally if the fossil is not formed from a form of an acid soluble compound or a carbonate or siliceous compound but is still organic, it is classed as an acritarch) and the diversity or the paucity of these species recorded in sedimentary rocks reflects the state of the planet with reference to the past ecological events (palaeoenvironment). The acritarch, as you may find out, can represent the remains of the three aforementioned life domains (remember LUCA) of archaea, bacteria and the eukaryote. The presence of the acritarchs found within the Tonian period tend to be chlorophyta (green algae) and fungi ( a form of eukaryotic life that forms a large group of great importance still to life today). Where would Whatlington and Vinehall Street be without beer and bread (both need yeast)?

Next time - the Cryogenian Period

The Christmas Quiz with answers

As promised and slightly late. As it is traditional with Christmas, please find a Christmas quiz, the answers will follow on another post but, of course, the answers are within the blog.

Lucky you - the answers are given here with links to the articles.

1) Who allowed the choir of Whatlington Church out early to get conkers from the church yard?

Mr. Ken Crouch

2) What did the term "plough" imply on an entry in the Domesday Book?

The term "plough" implies eight oxen with the plough, Whatlington had land for six ploughs.

3) What food and drink have the two villages produced? 

The villages have produced barley, beef, lamb, potatoes, raspberries, strawberries, wheat and wine (both red and white).

4) What is the name of the village group that follows the Sussex Fire and Firework Festivals?

The Whatlington Renegades

5) What are the compounds in leaves that provide the orange, red and yellow colourations in autumn?

Carotenes (orange), red (anthocyanins) and yellow (xanthophylls) in the falling leaves.

6) What was the name of the lady who was in charge of the village hall in the seventies who lived in Park Lane?

Miss Pratt

7) What was the first name on the list from the Great War on the War Memorial in Whatlington Church?

Gillachrist Moore

8) What was the first natural force that separated after the Big Bang event?

Gravity

9) What is the age of the Planet Earth when compared to the age of the Universe?

A third

A History of Whatlington and Vinehall Street - A Christmas Quiz

As it is traditional with Christmas, please find a Christmas quiz, the answers will follow on another post but, of course, the answers are within the blog.

1) Who allowed the choir of Whatlington Church out early to get conkers from the church yard?

2) What did the term "plough" imply on an entry in the Domesday Book?

3) What food and drink have the two villages produced?

4) What is the name of the village group that follows the Sussex Fire and Firework Festivals?

5) What are the compounds in leaves that provide the orange, red and yellow colourations in autumn?

6) What was the name of the lady who was in charge of the village hall in the seventies who lived in Park Lane?

7) What was the first name on the list from the Great War on the War Memorial in Whatlington Church?

8) What was the first natural force that separated after the Big Bang event?

9) What is the age of the Planet Earth when compared to the age of the Universe?

Happy Christmas 

Christmas Reading - Have a break from the history of the Planet Earth

It is Christmas Time and often book are given as gifts. 

If you are bored of me talking about the history of the Planet Earth, can I suggest you read from a few of these books:

Bill Bryson A Short History of Nearly Everything - It can be found as an illustrated version here or it can be found as a pdf here.

Richard Dawkins - The Magic of Reality - It can be found here as an illustrated copy.

Later today - a Christmas quiz on the early days of the Whatlington and Vinehall Street Archive, answers will be revealed on Boxing Day and then the history of both Whatlington and Vinehall Street will continue. 

Happy Christmas to all our readers across the globe.

Planet Earth - The Stenian Period - The jigsaw on Boxing Day

The Stenian Period ran from 1,200 to 1,000 million years ago and was the last period of the Mesoproterozoic Era. The name derives from the Greek word for narrow polymetamorphic (many rocks that are changed by heat and pressure) bands created within the rock.

The Rodinian supercontinent starts its main construction time of this supercontinent spanned from 1,100 to 780 million years despite some of the material having been already established in the last period, Ectasian. The name Rodinia comes from the Russian for "birth". The evidence for this supercontinent is found within the orogenies of the time (Dalslandian in Europe, the previously mentioned Grenville in North America and the Uralian in Siberia). With geological evidence, it is thought that Rodinia was centred south of the equator. Rodinia is thought to have comprised of the Amazonian Craton, Australia, the Congo Craton, Eastern Antarctica,  the Eastern European Craton, India, the Kalahari Craton, the North American Craton, the Rio de la Plata and Sao Francisco Craton, the West African Craton. So, basically a supercontinent made up of jigsaw parts of huge cratons. 

After the break up of the continent around 780 to 750 million years ago, the fragments became part of the supercontinent Pangaea.

Next time - The Neoproterozoic Era and the Tonian Period

Planet Earth - The Ectasian Period - Caution contains first record of sexual reproduction

The Ectasian period that dated from 1,400 to 1,200 million years ago is the second of three periods that make up the Mesoproterozoic Era. So why the picture above - read on and you'll find out why.

The term Ectasian comes from the Greek word for "Extension" and relates to the continuing expansion of the continents by the progression of sedimentary and volcanic deposits that continue, during this period, to cover the craton (the older and more stable part of the craton). This extension helped to form the basis of the  supercontinent Rodinia, which lasted from 1,100 million years to 780 million years ago, through the break up of the previous supercontinent, Columbia, and through accretion. A mountain range building event, known as the Grenville orogeny, that ran from the Labrador coast to Mexico on the North American continent was also formed over a series of events; it should be noted that part of Scotland has evidence of this orogeny.

It should be noted that this period is potentially the first recorded time that sexual reproduction had been recorded. A form of red algae (Bangiomorpha pubescens - a form of eukaryote) left its microfilaments as a fossil in the Hunting Formation on Somerset Island in Canada and is dated around 1,200 million years old. The microfilaments are evidence for complex multicellularity - multicellular organisms contain cells that perform specialised functions. Sexual reproduction has to solve the problem of generating an organism from germ cells (a biological cell that produces gametes of a sexually reproducing organism and a gamete is a cell that joins with another cell during fertilisation).

Previously asexual reproduction, the direct copying of cells without the fusion of gametes into an organism, meant that multicellularity could not exist. So, therefore, it stands to reason that both multicellularity and sexual reproduction and fossilised records of the former are all geological markers within our history of both Whatlington and Vinehall Street 

There is an interesting article about the chemical properties of early life that can be found here.

Next time - The Stenian Period