One's personality is both a composition and reflection, but if I have to choose one of them, I will choose reflection as the "self" is more important to me than "me". One's composition may change, walking across the cultural landscapes and climbing the social ladder but one's self is tied to one's reflections. The fun part is that reflections are not bound to "Time-Space" barriers ( it is not time-space) and respective mental constructs, which have grown so thick over ages, that they had reduced the image of humans to Sisyphus, rolling different sizes of boulders on hills of different heights.… As the name of this Blog indicates, knols are my perspectives on topics of interests, sweet/bitter experiences or just doodling :)

Monday, January 2, 2012

Interesting Times; The divorce between Capitalism and Democracy

The rise of China as an economic power with a single party government have put BIG question marks to a wide range of systems. Some of former Soviet Union administrators had frequently expressed their regrets (Please watch the video provided at the end of this Knol for one of expressions) that the decisions were made in hurry without investing much thinking in it. China has not only escaped a collapse but instead soar in global arena. It an open secret that the rise of China was not because of changes in political system but was rather achieved by economic reforms. This is a very clear demonstration that economy is more crucial in stability than politics. Soviet Union tried to solve an economic problem by a political reforms/transitions and the results were disastrous not only for Russia and other central Asian states but also on South Asia, Middle East and on West equally. After more than a decade of terrorism and "counter-terrorism" wars and global economic melt down people have just realized that Soviet Union was actually a shield of stability.

By expressing regrets nothing change but it seems that world is not ready to learn from past experiences. What is happening in the Middle East is the repetition of the same mistake. So called "Arab Spring" started because of deepening economic disparity in the Arab World, especially in North Africa but the solutions are coming as political. Does political changes have the capacity to solve the economic problems? The Soviet and Chinese models are providing a very clear answer to the question.

Of course, the opposite is also true. If there is a genuine political problem like a cultural group wanting self-determination then economic solutions might work for short time period but on long, political problems are only solved by political solutions. This is what happening in Bahrain, Saudi Arabia, Syria and Iraq for example.

I think, European Union is also learning from China. Europe in general like to present herself as capitalist democracy but the economic crises have pushed Europe to make exceptions/undermine democratic values and to go for tough austerity measures. People have to bear the costs of economic experiments.

The Occupy Wall Street movements in USA and the police responses to them do not make much sense in a democratic country. This is not a movement against state or system but a collision between people and corporations. People think that their rights have been undermined by corporations' undemocratic influences over state.

Until now, it was believed that one of the biggest causes of Persian, Turk, Mongol and Arab empires to collapse was the absence of corporations. The absence of corporations not only made the economic successes short lived but with no big impacts on society in general. So despite of having oldest and long periods, the people of these empires had not benefited from them and are now counted as third world countries. I agree with this point of view. On other hand we are also witnessing that corporations on long run do not allow democracy to function properly.

In short, democracy have been undermined by economic systems whether it was by one party system or by corporations. The Success of Chinese model and undermining of democracy by corporations have soured the relationship of capitalism and democracy. Slavoj Zizek terms it as a divorce between capitalism and democracy and of course it is interesting to see how this relationship will go....

Following is Slavoj Zizek' interview with Aljzeera. It looked interesting to me, you might also like it as we all need fresh eyes to look at what are happening around us...

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Sunday, January 1, 2012

Geographical origins of ancient civilizations

(This is an unfinished knol)

Background:
- The first human civilizations originated at Tropic of Cancer.
- Most land area in tropic of cancer is desert or semi-desert area.
- There are three main types of plate boundaries, convergent, divergent and transform fault. It is interesting to note that,
+ Masopotamia originated along Euphrates-Tigris rivers flowing from mountain chains, created as a result of transform plate boundary.
+ Indus Civilizations originated along Indus-Ganges rivers, flowing from mountain chains, created as a result of convergent plate boundary.
+ Ancient Egyptian Civilization originated along Nile river, flowing from mountain chains as a result of divergent plate boundary.

Tropic of Cancer:
It is an imaginary line, runs around the globe at 23.5 degree of equator in northern hemisphere. In tropic of cancer, the sun is directly overhead at noon, on 21st June and 21 August. It is the hot and arid zone. The seasonal changes is slight year around. Why tropic of cancer is hot and dry with less seasonal change. Just a glance on the atmospheric currents makes clear everything.


Diagram Source: http://mynasadata.larc.nasa.gov/images/AtmosphCirc2.png
If you look at diagram above, the winds take the humdity of the tropics and carry them to northern temperate regions and middle equatorial regions and so cause raining in those regions. In simple words the winds from temperate and equatorial regions steal humidity of tropics and turn these regions into desert or semi-arid regions.

Geography of ancient civilizations:

It is not accidental that earliest human civilizations, Mesopotamia, Indus valley civilization and Egyptian Civilizations were emerged on the Tropic of Cancer. In the second phase the next two major civilizations, Chinese and earliest Greek ones appeared in the vicinity of Tropic of Cancer further north. In third phase, human spread southward towards equator but still kept distance from equator. Certainly there is a deep correlations with increasing abilities of human and choosing areas to inhabit.

Image Source:
https://qed.princeton.edu/getfile.php?f=Ancient_Civilizations_of_the_Old_World_3500_to_after_600_BCE.jpg

Image Source:http://blue.utb.edu/paullgj/geog3320/lectures/map_of_ancient_civilizations.gif

How Plate tectonics influenced origin of earliest human civilizations?
The current positions of continents, landscapes, water bodies on the continents and oceans are the result of the plate tectonic activities over 4.5 billion years. It is interesting to note how plate tectonics have influenced the evolution of human civilizations. If we look to tectonics of areas where earlies human civilizations emerged, we see a close correlation between rivers flowing out from moutain chains and direct sun in arid areas, with less precipitation or with seasonal precipitations. The Collision of Indian Plante with Eurasian Plate created Himalayan mountain chian which is the source of Indus river and river valley civilization. Similarly, the Collision of Arabian Plate with Eurasian Plate created the Zagros mountain chain, Makran Mountain Chains and also Eastern Anatolian transform fault. The Eastern Anatolian Transform fault is the source of Three river systems, Aras, Euphrates and Tigris. The south flowing Tigris and Euphrates river created Euphrates valley which is the cradle of human civilization. It is not only collisions that create large mountain chains and rivers to support human civilization but divergent of plates also create valleys and river systems to support human civilization. One classic example is that of Ancient Egyptian Civilization. East African Rift has created largest lake of African continent (Lake Victoria) and longest river system on the earth, the Nile river.

East Anatolian Transform Fault (Between Arabian Plate and Anatolian Block)

Image Source:http://neic.usgs.gov/neis/eq_depot/2003/eq_030501/neic_tgac_anaflt.gif

Image Source: http://neic.usgs.gov/neis/gifs/iran_plates.gif

Image Source: http://pubs.usgs.gov/gip/dynamic/graphics/FigS8-2.gif
Northward drift of Indian Plate and Collision of with Eurasian Plate created Himalayan mountain chians.

Image Source:
http://itac.glp.net/uganda_ptc/sst/unit%209/images/The%20Eastern%20Africa%20Rift%20Valley.gif

The East African Rift is a divergent Plate boundary which is dividing the African Plate and also creating a new ocean (Along Red Sea: Red Sea is expanding and Persian Gulf is closing). East African Rift is creating several Lakes, most notably is the largest lake of African continent (Lake Victoria) and the most important river system, Nile River.

China’s geographical location: challenges and opportunities

Almost all ancient civilizations died one way or another except Chinese civilization. Archeologists search ancient Egyptian civilization in pyramids, Babylon in ruins of Babylon, Indus civilization in ruins of Mohenjo-Daro, Mehrgarh, Harappa, Lothal, ancient Persian Empire in Persepolis, and ancient Rome in ruins of Colosseum (Coliseum) and so on. Archeologists search them in ruins to reveal more details about them. The ancient civilizations have died long ago, and we need to learn about them from what left of them in the form of ruins. On the other hand, Chinese civilization is a living fossil. Chinese dynasties came and gone, form of governments changed but Chinese civilization remained intact. How was it possible? It is the miracle of Chinese geographical location.

Image source:http://www.chinapage.com/map/map.html

China’s geographical location was always attracted geographers, political and economical scientists (and also paleontologists to hunt Dinosaurs). If until modern times the Southern China Sea, the Western Mountain chains of Himalayas and North western Altai Mountain Chains and Northern Gobi deserts were protecting this civilization from foreign invaders, in modern times, each one of this geographical barrier turned into a new door of wealth and opportunities.

It is a historical agreement that China has a very favorable geography which makes it both sea power (South China Sea, Pacific Ocean, and Indian Ocean) and Land power, (Central Asia and Middle East (Through Pakistan, its key friend). China has 18000 Km long and temperate coastline, which stretches from South China Sea to Yellow Sea, Korea Bay and East China Sea. South China Sea is the largest manufacturing hub of world. China itself along with Japan, Korea, Taiwan, Malaysia, and Singapore are manufacturing giants of world. Indian Ocean is the home and main route of fossil. Indian Ocean is called the arc of fossil fuel and Muslim world stretching from North Africa, Middle East to Central Asia. Being in center of manufacturing and energy homes and routes has turned the coastal areas of China as a source of commerce for the China. The challenge in South China Sea is that of frequent straits. You can easily find some of these
straits like,

- Korea Strait
- Taiwan Strait
- Malacca Strait
- Makassar Strait

China’s Southwest neighbors are home of most populous but poor areas of world including Nepal, Bhutan, Myanmar (Burma), Laos and Vietnam. These neighbors are also turning into great asset for China’s commerce and over time the value of this asset is increasing. As China’s economy is improving so is the labor cost. China is successfully competing in free market because of cheap labor. Currently Chinese factories are shifting more towards villages in search of cheap labor. However there is a limit for cheap labor. As there is pressure on relating the value of Yuan with global economy, so these poor and populous neighbors will provide cheap labor to China and make her able to compete and dominate the global economy.

Mekong River is connecting China a very cheap transport to not only cheap labor but also vast markets. We can say that Mekong River has a strategic economic importance and will play a vital role in rise of Chinese economic empire. Mekong River is 4,350 Km long and connect six countries starts from China, Myanmar (Burma), Laos, Thailand, Cambodia and Vietnam. Changing weathers and water falls make navigation difficult in this river however, these constraints are not things that could not overcome once the labor value become key in economic competitions.
Map of Mekong River
Image Source:
http://sebrinaandjustin.andalib.com/wp-content/uploads/2006/06/Mekong%20(Medium).jpg

When it comes to neighbors on land, China faces both challenges and opportunities. Western neighbors are Tajikistan, Afghanistan, Pakistan, and India. All these western neighbors are the source of security problems for China. The instability in Afghanistan, Pakistan and Tajikistan making Chinese concerned as these instabilities may spread to China especially to Muslim Province of Xinjiang. India is also the source of big trouble for China. There are territorial disputes between India and China. India is also expanding its military might especially in Indian Ocean which is a source of fossil fuel supply to China.

Image Source: http://www.atimes.com/atimes/Central_Asia/images/pipemap161209.gif

Though, Western neighbors are sources of concern from security perspective, however they are great sources of economical development for China. Pakistan as main ally of China is connecting China by land to Iran and Middle East. China is building the strategic, Gwadar port in Southern Province of Baluchistan to secure fossil fuel supply, in case of trouble in Indian Ocean or South China Sea. The same is true for Afghanistan and Tajikistan. Though, India is used and projected by West to balance Chinese influence in region however, the large population of India is a promising large market for Chinese goods, so China try to have a good economic relations with India.

The most important Northwestern neighbors are two Central Asian nations of Kazakhstan, Kirgizstan. Kazakhstan is fossil fuel giant of Central Asia and Kirgizstan is connecting China to the vast gas and Oil fields of another fossil fuel giant, Turkmenistan. China is really hungry for mineral and fossil fuel and its expanding economy demands for more fossil and minerals. Central Asian nations vast reserves of minerals and fossil fuel make sure continue supply of these resources. The Kazakhstan-China oil pipeline and Turkmenistan-China gas pipeline is example of fossil fuel supply lines.

On the north China is bordered with Mongolia and Russia. Vast Plains of Mongolia and Russia with their harsh weathers are devoid of population however, vast plains of Mongolia are promising for massive cultivation and agricultural products. It just needed investment in times, demands become high to invest in vast but harsh plains. Russia is a world power that has vast energy reserves but do not enjoy the temperate coast that China possesses. These two powers rely and will rely heavily in future. Russia need access to South China Sea’s economic growths and China needs fossil fuels that Russia has.

Over time, China has taught the world some lessons including but not limiting to,

- China taught new and emerging nations that initial closer to outside world in order to build and strengthen institutions and local technologies, skills and knowledge and businesses is a success key once opened to ruthless competition of globalization.

- Both China and Russia left socialist economy to adopt a free market economy. China slow and careful transformations while keeping nation intact under central government proved more successful and fruitful. On contrast Russia’s sudden transformation along with freeing, nations part of Soviet Union proved disastrous economically, socially and in terms of security as a whole.
- There were two kinds of amphi-powers; those were ocean empires and holding posts on lands like, Pheonicia, Venice, Portuguese and Dutch and those who were land empires with controlled Sea lanes like, Athens, Rome, Muslim, Spanish, British and US empires. China’s favorable location makes it both.

- Usually the concept of globalization is of westernization. This is true for a short period of time, however on long run it is the countries with large populations like China, India, South Asian, South China Sea and South American nations that will develop the global culture and will influence global life style and standards.

- Usually people look to globalization as a world of Post Soviet period. To some extent it is true; however, it is the digitization of technologies, businesses, education and cultural exchanges that have shifted the world to a global world. It is an inevitable process.
Conclusion: China’s geographical location parallels in importance to that of her economic gains and its impacts on world.

Central Asia's changing perspectives

Background:

Central Asia is the largest landlocked region on earth and is the heart of Asia. By lying in between Russia, China, Iran, Afghanistan and Pakistan it is the cradle of power, economy and security. Due Soviet occupation of the area and reliance on marine routes for trade and projection of power Central Asia lived in shadows. The emergence of new states created not only change the geopolitical situation but also geo-economical situation. The vast deposits of gas, Copper and Uranium make this area an attractive region for energy hunger Europe and China. From one side emerging economy of the largest republic in the region, Kazakhstan indicate the fast growth capacity of this region however the emergence of new ethnic and ideological conflicts in Uzbekistan, Tajikistan, Kirgizstan which stretch beyond the border of Central Asia into Afghanistan and Pakistan also show the instability of the region. It is called Central Asia because it lies in the center of Asia bordering on East to East Asia, On South to South Asia and somewhat West Asia, West to East Europe and Caspian Sea and on north to North Asia. Central Asia is mainly composed of five main countries of Uzbekistan, Tajikistan, Kirgizstan, Turkmenistan and Kazakhstan.



Image Source: http://www.sairamtour.com/centralasia/CentralAsiaMap.gif

Water and ethnicity

Central Asia is not only home to landlocked countries but also to landlocked sea like Caspian Sea and Aral Sea. Adding to these two seas is the world’s Twelfth
largest lake, Lake Balkhash. This Amu Darya and Hari River is two largest rivers of this region which connect this region to Afghanistan and Iran. These two rivers and along with Syr Darya is the bloodline of this arid and semiarid region. The Fergana valley is most fertile area of this region which is irrigated by two rivers Kara and Naryn Darya which join to create Syr River. The fertility of this valley attracted Uzbeks, Tajiks and Kirgiz, three out ethnicities of the region to the valley. This ethnic diversity is one of the major sources of conflict in the region and today this valley is divided into three republics of Uzbekistan, Tajikistan and Kirgizstan. Beside the ethnicity, the ideological and irrigating rivers are also the source of the conflicts. The effects of these conflicts can be sensed beyond Fergana valley into Afghanistan, Northwestern Part of Pakistan and also Xinjiang Province of China. In Soviet Period it was tried to solve the problem by changing the traditional multi-crop culture of into a single cash crop of the cotton and also by dividing the valley based on the ethnicities. This experiment failed and after Soviet era the valley is shifting to traditional multi-crop culture that is more sustainable. Though the geography and economy of the valley is linked however the fear of unrest makes Uzbekistan to close the border and divide the valley.

History:

Though this region is conquered by Alexander and then Han Chinese but the fame and Power of this region came through Islamic civilizations and Descendant of Genghis Khan who have adapted Islam as their religion. The famous cities of Samarkand and Bukhara were the cradle of Islamic Civilization. During Islamic Period the Turks from this region spread to neighboring areas to spread Islam. The most phenomenons are conquering India and Byzantine Empire. The Timor Lang headed his army to South and Southwest to conquer India and found the Mogul Empire in India. Also Turks from this region headed south to collapse Byzantine Empire and make it the home of Turks that is modern Turkey. Due to Turko-Mongolian and Islamic military expeditions and also geographical ties we cannot separate the Central Asia from Iran, Pakistan, Afghanistan, Mongolia and Xinjiang province of China and so it is not wrong to include them in Central Asia. The Russian and Subsequent Soviet occupation of the region separated it from Afghanistan, Pakistan, Mongolia, Iran and Xinjiang Province and pushed this region into dark shadows of isolation.

Playground of Big Powers;

Central Asia is resuming its history of playground for big powers. Currently it is the test ground for power projections and conflicts of interests between, Russia, China, USA and possibly EU. It is not only big powers but medium powers of region like, India, Pakistan, Iran and Turkey is also trying to expand their interests and increase their influence in the region. Before 1990, the world was much safer, as West and Soviet Union was balancing each other's power. However, the world, after 1990's are going to be increasingly more politically unstable, more insecure and economically declining. The Central Asia is suffering the worst of all. Which power is going to get greater share of the influence in the region depends on the share of the power in the security, political stability and economic cooperation in the region.

Changed Perspectives of Central Asia:

Once Genghis Khan grieved by poverty of his people due to isolation and harsh weather were looking to China, Persia, India and Middle East as sources of grains, cottons, people and gold as sources of power that were scarce on the plains of Central Asia. Silk Road which were connecting these settled areas were the source of his hope to change the fate of his people. He tried to do trade with neighboring Persia and China but settled people of these areas were not ready to do trade and share their riches with poor people of Steppe, so he was forced to use his last option and that is occupy.

Since that time a lot have changed. Industrialization has changed the nature of hunger. Grains and cotton have declined in importance as energy and minderal resources got importance. This time it is not Central Asian People looking to settled areas but the settled aread looking into Central Asia for more power. Energy and mineral hungry China, Europe, Russia, India, Pakistan, Turkey, South Korea and USA is looking to vast resources of these region.

Growth Capacity;

From nature to human societies, everything has a capacity in specified time. Sure time changes the capacity as I mentioned in the previous paragraph. It is of no wonder that US, Europe and Middle East's economies are on decline. They have consumed their capacities. Unless they do not create a new space as digital technologies created immense space for growth, this decline will be there. Central Asia on the other hand remained unexploited. Its natural, geographical and human resources promise a lot of growth in this region. I can see how the focus of great players is going to increase in this region and it will bring both opportunities and conflicts in this region.
External Sources;

1. Central Asia Water conflict and Solution;
http://blogs.ei.columbia.edu/water/2010/06/10/understanding-water-conflict-in-central-asia-and-solutions/
2. Central Asia on verge of conflict on water
http://en.ng.ru/energy/2008-04-08/1_water.html
3. Power Politics in Central Asia:
http://www.asiaquarterly.com/content/view/129/5/
4. Mineral Resources of Central Asia and Europe (USGS)
http://minerals.usgs.gov/minerals/pubs/country/europe.html

A response to Algeo-Scheckler’s “Terrestrial-marine teleconnections in the Devonian: Links between the evolution of land plants, weathering processes, and marine anoxic events”

A. Introduction

Before appearance of life on earth it was degassing from volcanisms, metamorphisms and weathering of silicate rocks that were regulating the carbon cycle. Volcanisms were supplying greenhouse gases like CO2 to atmosphere and weathering of Ca and Mg- Silicate rocks were drawing down CO2 from atmosphere to deposit them in form of carbonate rocks (Berner, 1983). The appearance of life on earth added biotic factor in global carbon cycle. One of the biggest events in geological history and also in evolution of Carbon cycle was the evolution of trees and seed plants which resulted in forestation and deep weathering of Silicate rocks (Beerbower et al. 1992). The forestation changed climate by working as a carbon sink and caused rapid drawdown of pCO2 that led to continental glaciations at the end of Devonian (Caputo 1985; Berner 1992, 1994). The rise of forests is correlated with widespread bottom water anoxia that was catastrophic for tropical benthos and coral reef communities (McGhee 1996). Sinking of organic matter and anoxia also resulted in deposition of Barite in Late Devonian Period (Paul, et al. 1994). The vegetative cover of land deeply affected the flow of water in terrestrial environments by strengthening of river banks, bars and changing the morphology of land. Meandering river system become more frequent as compared to prior vegetation cover of land when braided river system were dominating (Neil, et al. 2010). Prior to evolution of larger land plants in Silurian, virtually all river systems had a braided platform (Cotter 1978).

Thomas Algeo and Stephen Scheckler has recently (July, 2010) published a model to link all these events into a feedback system. Though this model covers beautifully most of the aspects of major impacts, tree evolution in a feedback system that changed both marine and terrestrial environments of Devonian Period however, this model is very brief with missing some important changes in feedback systems. There is no mention of forest fire though it was an important addition in Devonian ecosystem and perhaps climate. The rise of forests not only provided fuel but also oxygen level (more than 13%) for forest fire. A opposed to desertification, forestation was a main event that impacted the rate of evaporation and albedo. Eustatic sea level changes that many authors suggested a cause of mass extinctions in Late Devonian was totally ignored. The role of Arcadian orogeny is also totally ignored while Acadian orogeny may have played a vital role in accelerating silicate weathering of plants. All these events are important factors in marine-terrestrial teleconnections that was the main purpose of this flow chart model. Besides, Algeo-Scheckler model’s is showing that all subsequent events are related to Pedogenesis. Though Pedogenesis was an important outcome of arborescence and seed habit however we can’t overlook the roles of forestation and orogeny which were not only the main causes of Pedogenesis and silicate weathering but also had their independent role in marine-terrestrial teleconnections. For example, the landscape stabilization is shown as a result of intensified Pedogenesis while it is as a result of forestation and vegetative cover. Lastly it is needed to acknowledge the complications from parallel mechanisms for climate change and mass extinctions like orogeny, meteorite impacts and even orbital forcing of climate that is really difficult to link in distant geological time. Based on the above arguments I suggest for remodeling of this flow chart and I have redrawn it. Following is Algeo-Scheckler’s flow chart model and next to it, is my effort to amend this flow chart.

After Algeo et al, 2010

Above: Algeo-Scheckler’s flow chart model of marine-terrestrial teleconnections
Below: Redrawn flow chart model of Devonian marine-terrestrial-teleconnections


B. Discussion:

I. Physiological innovations and forestation:


During Early to middle Silurian bryophytic plants have started invading terrestrial environment. Although it was a big step in evolution of land plants however the reproductive and physiological limitations of the bryophytes kept them close to water bodies. Bryophytes are non-vascular, rootless, without stems and leafless thalloid plants that reproduce by spores (Beerbower et al. 1992). Lack of wood, kept them small and limited to wet environment so their invasion of terrestrial environments didn’t result in forestation and their role were limited in silicate weathering as product of their weathering were protosols. These physiological limitations of bryophytes limited their impacts on global carbon cycle, global climate and their role in marine-terrestrial teleconnections. It was Late Silurian and Early Devonian that vascular plants evolved and diversified (Gray, 1985). Though these land plants were small, shallowly rooted and limited to moist land areas but in Middle to Late Devonian Large trees with deep root systems like Archeopteride appeared that had colonized uplands. Algeo-Scheckler (Algeo et al, 2010) has presented artistically the evolution of vascular trees from early to late Devonian. The main innovation that led to differentiation of different plant systems (roots, branches, leaf) was appearance of wood. Raven (Raven, 2005) has pictured this phenomenon beautifully, “Scientists believe that once a lycophyte tree was stabilized by its shallow, forking, rootlike axes, it pushed rapidly skyward……”. By focusing more on impact of forestation of marine-terrestrial teleconnections, my focus will be on , a. environmental diversity of plants and on their size,

Early Devonian (Siegenian/Pragnian-Emsian) upland floodplain
After Algeo et al, 2010


Middle Devonian (Eifelian-Givetian) upland floodplain
After Algeo et al, 2010

Environmental diversity of land plants:

The range of environments that land plants have covered is key to understand the impact of their evolutionary innovations. Algeo-Scheckler’s reconstructions of environments of small, shallow rooted vascular plants in early Devonian and middle to large sized trees in Middle to Late Devonian show their environments as upland floodplains. Their reconstructions are supported by their own works on exposed beds of Franklinian Geosyncline that have exposures at High Arctic island of Canada and Famennian beds in Appalachian USA (Scheckler 1986a; Streel & Scheckler 1990). The flood plains that these trees have covered had diverse environments ranging from fluvial-deltaic to shore lines.

Scheckler (Scheckler et al, 1990) have compared the flora from meandering and braided river system and those of lowland and found that upland vegetation was similar to those of lowland but less diverse.

New York is famous for it’s in place tree stumps especially those of Gilboa village. In place tree stumps in New York regions are mostly found in Fluvial-deltaic, chiefly comprises of two formations of Plattekill and ManorKill formations which are successions of mudstone to sandstone that deposited in diverse range of environments. Bridge-Willis (Bridge et al, 1994) listed environments of Catskill formation from (i) Storm-wave-dominated muddy marine shelf with sandy shoals; (ii) sandy, tide influenced channels with wave- and tide-influenced mouth bars; (iii) sandy and muddy tidal flats, including channels, mouth bars, and washovers ; and (iv) muddy brackish bays, lakes and flood plains.


Late Devonian (Famennian) upland plain
After Algeo et al, 2010

2. Tree sizes (stem and roots)

Along with diversity of environment the size of trees and their rooting systems is another measure of impacts of evolutionary innovations. The large trunk sizes play as large reservoirs of carbon sinks and extensive rooting systems play main key role in weathering of Silicate rocks.
We see a rapid increase in trunk sizes, rooting systems and differentiation of different plant organs from simplest vascular plant of Early Devonian plants like Rhyniophytes to giant trees with extensive rooting like of Archeopterids of Late Devonian. Following I provide some representative plant assemblage of Devonian Period and also representative sizes just to show, how small plants turned into huge trees. This increase of size was a response to terrestrial environment.

i. Early Devonian assemblage:

Early Devonian plant assemblage includes Rhyniophytes, Trimerophytes and Zosterophylls. Rhyniophytes is thought to be oldest vascular plants and it is the simplest of all known vascular plants (Taylor, 1993). Rhyniophytes were small plants and they could reach the height of 30 cm (Renalia) though most of them were much shorter. Zosterophylls that are believed to be the ancestor of Lycopods could attain a height up to 50 cm (Gosslingia breconensis). Trimerophytes which were more complex than Rhyniophytes and Zosterophylls and their size could exceeds than a meter in height. Hence the plant assemblage of early Devonian was leafless with dichotomous braches ranging from few cm to a meter tall.

ii. Middle Devonian assemblage:

The Middle Devonian plant assemblage included Cladoxylalean ferns, Aneurophytes progymnosperms and Drepanophycales lycopods. Lycopods have originated from zosterophylls, had small leafs known as microphylls and most species were herbaceous. The diameter of their stem could reach 6.5 cm and leaves up to 4 cm long and they could reach to height of 50 cm tall. Cladoxylales are fern-like group of small trees; some of them (Pseudosporochnus) could reach 3 meters of height with a trunk that bore large roots and atleast three order of branches. Aneurophytes are the most primitive group (order) within progymnosperms, had three dimensional branching and their trunks from Gilboa, NY (Eospermatopteris), and is believed to 9 to 12 m tall.

iii. Late Devonian assemblage:

The Late Devonian plant assemblage included Zygopterid ferns, Archeopterids progymnosperms, Sphenophyll vines and Tree Lycopods. The elaborately frond bearing Zygopterid ferns were almost tree size as Austroclepsis from Lower Carboniferous of Australia had a trunk of 30 cm in diameter, consisting of numerous leaf bearing stems and intertwined roots. Archeopterids were large trees with extensive root system. Some specimen (Callixylon) had a woody of stem of up to 150 cm and a height exceeding 10 meters. Sphenophyll vines were small trees less than a meter and formed the understory of forests in Devonian and Carboniferous forests.

II. Forest Fire and marine-terrestrial teleconnections:

The most important point that is missing in Algeo-Schekler’s model is forest fire. Forest fire is an important event for Geology, Ecology, Climate and Paleobotany. Forest Fires could be traced by fossilized charcoal known as Fusian. Fusian are dominantly characoalified secondary wood but it may include other plant parts like leaves and seed (Scott et al, 1991) and hence they are important for Paleobotanists as they provide valuable information about the Plants that were constituted forest. Fusian is very important for paleoclimatologists because, forest fire is only possible when atmospheric oxygen level exceeds 13% and it charcoal will not form if atmospheric oxygen content exceeds that of 35% as it burn out the whole woods (Scott et al, 1991). The Fusian along with spores and megafossil may also tell the succession of trees.
Forest fire is important in marine-terrestrial teleconnections of Devonian period to explain the episodic erosional surfaces of black of Devonian. Schieber (Schieber et al al, 2004) identified four regional erosional surfaces in Chattanooga Shale. Algeo-Scheckler’s model linked the black shale to intensified Pedogenesis during Devonian Period. Though intensified Pedogenesis must have played a key role in deposition of black shale however it can’t explain the erosional surfaces of black shale because Pedogenesis was an increasingly intensifying event with evolution of trees. Erosional surfaces could be better explained by transgressive-regressive cycle, orogeny and perhaps also forest fires which are episodic and occur more frequent in hor and climate or during freuquent volcanisms. Pedogenesis, Arcadian orogeny, eustatic sea-level changes and forest fire combined provide a plausible explanation for episodic black shale deposits. Black shale basin of Late Devonian used to measure the rate of Arcadian orogeny (Ettensohn et al 1987). Black shale was deposited in foreland basin and the rate of Arcadian orogeny was exceeding 7 cm/year, so we would expect high terrigenous influx which is adding complicate linear explanation of events.

III. Forestation cover, Fluvial systems, Pedogenesis and Silicate weathering:

Though forestation was not the only big event in Devonian Period but it was the single only event that caused a series of big events of Devonian Period that were related to it like, landscape stabilization, decrease of desertification, intensified Pedogenesis, forest fire and increased O2/CO2. Appearance of root system and their rapid lateral and downward growth and anchorage not only helped in enlargement of plants to tree size but also intensification of the Pedogenesis.

Change in Fluvial Systems:

One of the most obvious impacts of forestation was the landscape stabilization. Big differences in alluvial and fluvial sedimentation and fluvial system have been reported. Davies-Gibling (Davis-Gibling et al, 2010) have compiled the case studies and made a database of subject from Cambrian to Devonian. They constructed a flow chart of feedback system showing inter-relationship of fluvial systems prior evolution of root system of terrestrial plants. It make easy to understand major changes in alluvial system and sediment characteristics after the evolution of root systems. Pre-Devonian fluvial succession characterized by lack of fine grained sediments, were dominated by bedload-dominated transport, unstable banks and flashy discharges showing braided river system characters (Schumm, 1968, Eriksson et al., 2006). Cotter reviewed (Cotter, 1978) 39 published studies on fluvial system from Precambrian to Devonian and found only two reports of pre-Silurian meandering system. Though some authors like Bridge (Bridge, 2006, p.156) has criticized this approach by Cotter however, Vandenberghe (2001, 2003) has provided more evidence on impact of vegetation on fluvial system from preglacial river systems. Whether a system adopts a meandering system or braided systems depends on patchiness of vegetation.

Flow chart of feedback loops of alluvial system prior to vegetation.
After Davies and Gibling et al, 2010

Root systems and vegetation cover of the trees and plants of forest, stabilized river banks and helped to change the dominant braided river system to increasing meandering river system.

2. Silicate Weathering and Pedogenesis:

Algeo-Scheckler (Algeo et al, 2010) have illustrated it beautifully, showing that soil penetration was shallow in Middle Devonian by less 20 cm which increased by Late Devonian to more 80 cm. Vascular plants affect silicate weathering by multiple processes, (i) acidification of soil by organic acids, (ii) increasing residence of water (iii) Increasing the depth of weathering by deep penetration of root systems.

After Algeo-Scheckler et al, 2010

The evidence for intensification of chemical weathering of silicate rocks comes from difference of sedimentation prior vegetation and after the vegetation cover. Prior to vegetation and in absence of K-chelation, K-feldspar have been more stable in terrigenous sediments (Ranganathan, 1983) and hence arkosic and to subarkosic sandstone were more common in fluvial sandstone (Hiscott et al., 1984).


IV. Eutrophication, Glaciation, Sea level variation and Mass extinction:

Due to opposing reports and disagreements among researchers about causes of Late Devonian eustatic sea-level changes and mass extinctions it is not easy to establish an acceptable mechanism for Anoxia and sea level changes and extinctions. However, the coincidence of certain events makes us able to have a general explanation. There were two extinction events in Late Devonian, the first one between Frasnian-Famennian (F-F) and second one between Devonian-Carboniferous (D-C) boundary (Sepkoski, 1996). F-F mass extinction is one of the big fives of mass extinctions (MaGhee,1996). One important aspect of this mass extinction is that most of its victims were shallow, warm-water taxa, reef taxa and pelagic taxa (Hallam and Wignall, 1997) however deep and cold water taxa survived mass extinction (McGhee, 1996).

The episodic mass extinctions as well as survival of cold, deep-water taxa make it difficult to explain the mass extinction as a result of eutrophication from increased nutrient flow as a result of Pedogenesis alone. However, eutrophication becomes a likely factor when it coincides with other processes to accelerate the process of mass killings. Some authors like Newell (Newell, 1967) and Johnson (Johnson, 1974) suggested a rapid regression was the cause of F-F mass extinction, however extinction process was started during high sea level and continued to regression during F-F mass extinction event. There are reports of two regressive-transgressive cycles during mass extinction event. Based on these two cycles Buggisch (Buggisch, 1991) provided an attractive mechanism to link eustatic sea-level changes with marine-terrestrial events to F-F mass extinction.

After Hallam-Wignall et al., 1999

The event begins with transgression which starts two simultaneous processes. Firstly, transgression floods the shelf area and makes a deep and anoxic environment which results in mass killings of benthos. Secondly, transgression bury large amount of organic carbon which initiate global cooling that triggers glaciations. Glaciations cause the sea level drops and expose the organic carbon for oxidation. The oxidation of organic carbon increase CO2 level in atmosphere which in turn results in warming and melting of ice and hence another transgression. Though this mechanism seems explains well the rapid icehouse and greenhouse cycles during F-F mass extinction however, evidences from Morocco and Poland do not show evidences for transgression and regression cycles as you can see in figure of eustatic sea level curves of the period and it is only North America and South China that support the suggested mechanism.

V. Conclusion:

Despite of somewhat contradicting evidences and explanations, the evidences for two stages mass extinctions, two cycles of eustatic sea level changes at least in large part of globe if not all the whole globe, black shale deposits, sulfide and sulfate {Barite deposits (Jewell et al., 1994)} deposits, increased Pedogenesis and change in characteristics fluvial sediments and fluvial systems show unusual conditions in Late Devonian that could be link to rise of forests. Having said that it is noteworthy that all these events were not linear and solely as a result of rise forestation but forestation played a major role to accelerate these events. Hence it is more logical to not overlook other processes during Devonian when constructing a model for marine-terrestrial teleconnections.

References:

Andrew C. Scott & Timothy P. Jones, “Fossil charcoal: a plant-fossil record preserved by fire”, 214/Geology Today, November-December 1991.
2. A.Hallam, P.B. Wignall, “Mass extinctions and sea-level changes”, Earth-Science Reviews 48_1999.217–250.

3. Bickle, M. J., 2002, "Impact of the Himalayan Orogeny on Global Climate", American Geophysical Union, Fall Meeting 2002, abstract #GC61A-04 Time Table of Devonian Period

4. Berner, R. A., Lasaga, A. C. & Garrels R. M. (1983) Am. J. Sci. 283, 641-683.

5. Beerbower, R., Boy, J. A., DiMichele, W. A., Gastaldo, R. A., Hook, R., Hotton, N. III, Phillips, T. L., Scheckler, S. E. & Shear, W. A. 1992 Paleozoic terrestrial ecosystems. In Terrestrial ecosystems through time (ed. A. K. Behrensmeyer, J. D. Damuth,W. A. DiMichele, R. Potts, H.-D. Sues & S. L.Wing), pp. 205^325. University of Chicago Press.

6. Bridge, J.S., 2006. Fluvial facies models: recent developments. In: Posamentier, H.W., Walker, R.G. (Eds.), Facies Models Revisted SEPM: Society for Sedimentary Geology, pp. 85–170.

7. Buggisch, W., 1991. The global Frasnian–Famennian ‘Kellwasser event’. Geol. Rundsch. 80, 49–72.

8. Cotter, E., 1978. The evolution of fluvial style, with special reference to the central Appalachian Paleozoic. In: Miall, A.D. (Ed.), Fluvial Sedimentology: Canadian Society of Petroleum Geologists Memoir, vol. 5, pp. 361–383.

9. Eriksson, P.G., Bumby, A.J., BrĂ¼mer, J.J., van der Neut, M., 2006. Precambrian fluvial deposits: enigmatic palaeohydrological data from the c. 2–1.9 Ga Waterberg Group, South Africa. Sedimentary Geology 190, 25–46.

10. Frank R. Ettensohn, “Rates of Relative Plate Motion during the Acadian Orogeny Based on the Spatial Distributionof Black Shales”, The Journal of Geology, Vol. 95, No. 4 (Jul., 1987), pp. 572-582.

11. Gray, J. 1985 The microfossil record of early land plants: advances in understanding of early terrestrialization, 1970^ 1984. Phil.Trans. R. Soc. Lond. B 309, 167^195.

12. Hallam, A., Wignall, P.B., 1997. Mass Extinctions and Their Aftermath. Oxford Univ. Press, Oxford.

13. Hiscott, R.N., James, N.P., Pemberton, S.G., 1984. Sedimentology and ichnology of the Lower Cambrian Bradore Formation, coastal Labrador: fluvial to shallow-marine transgressive sequence. Bulletin of Canadian Petroleum Geology 32, 11–26.

14. J.S. Bridge, B.J. Willis, “Marine transgressions and regressions recorded in Middle Devonian shore-zone deposits of Catskill clastic wedge”, Geological Society of America Bulletin, v. 106, p. 1440-1458, November 1994.

15. McGhee, G.R., Jr., 1996. The Late Devonian Mass Extinction. Columbia Univ. Press, New York.

16. Neil S. Davies, Martin R. Gibling, “Cambrian to Devonian evolution of alluvial systems: The sedimentological impact of the earliest land plants”, Earth-Science Reviews 98 (2010) 171–200.

17. Paul W. Jewell, “Paleoredox conditions and origin of bedded barites along the Late Devonian North American continent margin”, The Journal of Geology, 1994, volume 102, p. 151-164.

18. Peter H. Raven, Ray F. Evert, Susan E. Eichhorn, “Biology of Plants”, Seventh Edition, W. H. Freeman and Company Publishers, 375.

19. Ranganathan, V., 1983. The significance of abundant K-feldspar in potassium-rich Cambrian shales of the Appalachian basin. Southeastern Geology 24, 139–146.

20. Sepkoski, J.J., 1996. Patterns of Phanerozoic extinction: a per-spective from global data bases. In: Walliser, O.H. _Ed..,Global Events and Event Stratigraphy. Springer-Verlag, Berlin, pp. 35–52.

21.Schumm, S.A., 1968. Speculations concerning paleohydraulic controls of terrestrial sedimentation. Geological Society of America Bulletin 79, 1573–1588.

22. Thomas J. Algeo and Stephen E. Scheckler, “Terrestrial±marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events”, Phil.Trans. R. Soc. Lond. B (1998) 353, 113^130.

23.Thomas N. Taylor, Edith L. Taylor, 1993. “The Biology and Evolution of Fossil Plants”. Prentice Hall, Englewood Cliffs, New Jersey, pp. 201, 208, 221, 235- 239, 352, 451-452, 380, 444, 307.

24. Vandenberghe, J., 2001. A typology of Pleistocene cold-based rivers. Quaternary International 79, 111–121.Vandenberghe, J., 2003. Climate forcing of fluvial system development: an evolution of ideas. Quaternary Science Reviews 22, 2053–2060.