冰川与地球分享 http://blog.sciencenet.cn/u/rock6783 求真、求实、识友

博文

The Effect of Biotic Evolution on Glacier

已有 5736 次阅读 2008-2-8 13:00 |个人分类:生活点滴|系统分类:科研笔记

  

The Effect of Biotic Evolution on Glacier

    Liao Yongyan

Fisheries college of Guangdong Ocean University, Zhanjiang, 524025, China

E-mail: rock6783@126.com

Abstract: By comparing and analysing the present data about paleo-biology, geology, geophysics, geochemistry, paleo-climatology and paleo-glaciology, it turns out that the glacier formation resulted from the photosynthesis of the plants consuming CO2, depositing mineral organic matter, causing the reduction of the greenhouse effect. The whole glaciers melting resulted from the degasification of the earth causing by volcanic eruption and earthquake, and the deduction of live-weight in glacial epoch. The glacial epoch of 3.5 billion years ago was formed by both the weathering effect and photo-synthesis effect that does not produce O2 together. The glacial epoch of 2.9~2.7, 2.4~2.3 billion years ago were formed by prokaryotic myxophytes. The glacial epoch of 0.8~0.9 to 0.57 billion years ago was formed by unicellular eucaryotic algae, and the appearance of phytophage animals took part in the ending of the glacial epoch. A lush growth of multicellular algae brought about glacial epoch in the end of the Ordovician period, and the appearance of animals living on these algae took part in the ending of this glacial epoch. The Carboniferous and Permian glacial epoch were formed by the lush growth of pteridophyte. When the pteridophyte died off heavily on account of being not able to adapt to the cold and dry conditions after glacier formation, this glacial epoch ended. Having not finished yet so far, the Quaternary glacial epoch were formed by the lush growths of gymnosperm and angiosperm. The Quaternary glacier evolved gradually with the effect of forest fire that owe to excessive O2 concentration in the atmosphere, and the gradual evolution of plants that aroused the glaciers together.

Key words: Glacier, Biotic evolution, CO2, O2, Greenhouse effect, Forest fire, H+ concentration. pH value.

 

Because of the existence of the Quaternary glacial Ages, glacier can still be seen now on the polar regions and high mountains of the earth[1]. As for the frequency of glacial age, there are different versions in the geologic history[2], some believe that there are only four[3], some divide the glacial age of the Proterozoic Period and before into 3~5[4].

There were many theories that illustrated and described the reasons of formation and melting of glaciers in the geologic history. Some scholar held that the formation of glacier resulted from the periodic slow change of the angle between the rotation axis of the earth and ecliptic plane[5]. And later explanation for the glacier formation came from “Dynamic inclined modal”[6]. Till 1990’s, based on the rich data and evidence about paleomagnetics, isotopy, geophysics including carbonate sediment, geochemistry and paleobiology, Kirschvink and other scholars put forward “Snowball Hypothesis”[7-8]. The “Snowball Hypothesis” modal described that glacier formation in the Neo-Proterozoic glacial Age resulted from reduction of effect of greenhouse effect of CO2. But the hypothesis has not explained the causes of glacier formation in other glacial age, so it is necessary to carry out a comprehensive study of the cause of glacier formation in the earth.

1  The theory of the equilibrium of H+ concentration of the earth and the sediment of organic Carbon

If pHCO2<pH<pHCO32-( pHCO2 is the pH value that all the HCO3- in the solution are counteracted by H+; pHCO32- is the pH value that all the HCO3- in the solution are counteracted by OH+), the pH value of the solution will be within the buffer range of carbonic system, and the carbon can flow ceaselessly among the atmosphere, biosphere, hydrosphere, and lithosphere. Finally, the organic matter that is produced by photosynthesis of plants, the CO2 in the atmosphere, the CO2, HCO3-, CO32- in the seawater (or all the water of the earth), and the carbonatite in the lithosphere can keep equilibrium as Fig.1[9]:

 

 

Fig.1 Chemical equilibrium of the carbonic system

 

Since the carbonic acid is dicarboxylic acid, the ionization of carbonic acid has two steps, then, there are the equations as follows:

K1=αH+×αHCO3-(T)/αH2co3(T)                                1

K2=αH+×αCO32-(T)/αHco3-(T)                                 2

The K1 and K2 are the thermodynamics constants. When the apparent ionization-coefficient, K/, is adopted, the equations are showed as follows:

K1/=CH+×CHCO3-(T)/CH2co3(T)                                    3

K2/=CH+×CCO32-(T)/CHco3-(T)                                     4

Taking logarithmic transformation for 3 and 4, the equations is show as follows:

pH=pK1/+logCHco3-(T)/CH2co3(T)                                 5

pH=pK2/+logCco32-(T)/CHco3-(T)                                 6

Also, the equations of (5) and (6) can be showed as follow:

pH=1/2(pK1/+ K2/-logCco2(T)/Cco32-(T))                           7

So, besides the effects of temperature, pressure and salinity, the pH value varies mainly with the ratio of concentration of CO2 and CO32-. Thus, when the pH value is high, the relative proportion of CO32- is high and the relative proportion of CO2 is low. Vice versa.

Same as the carbonic system, when pHSiO2<pH< pHSiO44- (pHSiO2 is the pH value that all the H3SiO4- in the solution are counteracted by H+; pHSiO44- is the pH value that all the HSiO43- in the solution are counteracted by OH+), the pH value of the solution will be within the buffer range of silicic system, and the silicon can flow ceaselessly among biosphere, hydrosphere, and lithosphere. Finally, the SiO44-, HSiO43-, H2SiO42-, H3SiO4- and H4SiO4 in the seawater (or all the water of the earth) and the sediment siliceous rock and the silicate rock in the lithosphere can keep equilibrium as Fig.2.

 

 

 

Fig.2 Chemical equilibrium of the silicic system

 

Same as the carbonic system, the pH value also influence the ionization of silicic acid. So, there is the equations as follows:

pH=pK1//+logCH3SiO4-(T)/CH4SiO4(T)                               8

pH=pK2//+logCH2SiO42-(T)/CH3SiO4-(T)                              9

 pH=pK3//+logCHSiO43-(T)/CH2SiO42-(T)                             10

 pH=pK4//+logCSiO44-(T)/C HSiO43-(T)                              11

(The K// are apparent ionization-coefficient)

The equations of (8), (9), (10) and (11) can be showed as follow:

pH=1/4(pK1//+pK2//+pK3//+pK4//-logCH4SiO4(T)/CSiO44-(T))                  (12)

So, besides the effects of temperature, pressure and salinity, the pH value varies mainly with the ratio of concentration of H4SiO2 and SiO44-. Thus, when the pH value is high, the relative proportion of SiO44- is high and the relative proportion of H4SiO4 is low. Vice versa.

If the silicic system and the carbonic system can keep equilibrium in seawater, the pH values of the silicic system and the carbonic system will are same. Then, there is the equation as follow:

 pH=1/2(pK1/+ K2/-logCco2(T)/Cco32-(T))

     =1/4(pK1//+pK2//+PK3//+pK4//-logCH4SiO4(T)/CSiO44-(T))      (13)

Thus, the pH value of seawater will be decided by ratios of Cco2(T)/Cco32-(T) and CH4SiO4(T)/CSiO44-(T) together.

The HCl and HF dissolve to the water, there are equations as follows:

 

 

                              

When a lot of HCl and HF that resulted from the degasification of volcanism and earthquake[10-15] dissolving to seawater (or all the water of the earth), the concentration of H+ in the seawater increased, and the pH value decreased. Same as the HCl and HF, when a lot of CO2 that resulted from the degasification of volcanism and earthquake dissolving to seawater(or all the water of the earth), the equilibriums of Fig.1 moved to right, the HCO3- and CO32- formed, and H+ was released into seawater(or all the water of the earth) and the pH value decreased, too. All the actions of HCl, HF, CO2, H2S, SO2 and other volatile gases together, made the concentration of H+ in seawater very high and pH value very low. When pH<pHCO2, the actions was made mainly by HCl and HF. When pHCO2<pH<pHCO32-, the action was made mainly by CO2, because the CO2 is the main gas of degasification of volcanism and earthquake.

When the concentration of H+ in the seawater increased, the equilibriums of Fig.2 moved to left, the SiO44- combined H+ to form the HSiO43-, H2SiO42-, H3SiO4- and H4SiO4. Thus the concentration of SiO44- decreased, and the concentration of H4SiO4 increased. Since there are the equations as follows:

K/spsiliceous =CH+(T)×CH3SiO4-(T)                                  16

     K/spsilicate=CCa2+, Mg2+, etc.(T)×CSiO44-(T)                            17

When the concentration of SiO44- decrease, if the K/spsilicate>CCa2+, Mg2+, etc. (T)×CSiO44-(T), the silicate rock will weather, until the K/spsilicate=CCa2+, Mg2+, etc. (T)×CSiO44-(T). And when the concentration of H3SiO4- increase, if the K/spsiliceous<CH+(T)×CH3SiO4-(T), the siliceous rock sediment will occurs, until the K/spsiliceous=CH+(T)×CH3SiO4-(T).

So, when the concentration of H+ in the seawater is high, the pH value is low, the action of silicate consuming H+ to weather is strong, and the action of CO2 dissolving to seawater to release H+ to form HCO3- and CO32- is faint, the carbonatite sediment do not occurs. When the concentration of H+ in the seawater is low, the pH value is high, the action of weathering is faint, and action of CO2 dissolving to seawater to release H+ to form HCO3- and CO32- is strong. When the K/spcarbonate<CCa2+( Mg2+)(T)×CCO32-(T), carbonatite sediment would occurs, until the K/spcarbonate=CCa2+( Mg2+)(T)×CCO32-(T).

So, the equilibrium of H+ in the seawater (or the pH value) results from the actions of silicic system and carbonic system together. In the process of the earth evolvement, while the CO2 of atmosphere dissolved to seawater to release the H+, finally, becoming the sediment carbonatite of lithosphere, the silicate rock weathering consumed the H+ becoming the sediment siliceous rock. Since 1 molecular CO2 becoming 1 molecular sediment carbonatite releases 2 molecular H+, while 1 molecular silicate rock becoming 1 molecular sediment siliceous rock consumes 4 molecular H+. If disregard the actions of HCl, HF and other volatile acid gases, when forming 6×107Gt(1Gt=109t) of sedimentary carbonatite in the earth[16], for keeping the equilibrium of concentration of H+, there will be 6×107Gt×60÷92.15÷2=1.95×107Gt sediment siliceous rock  to form in the earth (the molecular weight of SiO2 is 60, CaCO3s is 100, MgCO3s is 84.3; it is supposed that, CaCO3 and MgCO3 holding 50% respectively in the carbonatite; then the average molecular weight of carbonatite is 92.15). So, the carbonatite and the siliceous rock are the most main sediment rock in the earth. Besides the CO2, there are other volatile acid gases, such as the HCl and HF, in the degasification of volcanism and earthquake[10-15]. So, the quantity of sediment siliceous rock of the earth is more than 1.95×107Gt. So, the sediment siliceous rock is the sediment rock that only less than the carbonatite in the earth.

When the effect of silicic system equal the effect of carbonic system, the concentration of H+ in seawater is neither high nor low, and the pH value is neither low nor high. In this condition, the carbonatite sediment does not form, the siliceous rock sediment does not form, too, and the weathering is very faint.

Under the equilibrium that resulted from the effect of silicic system and carbonic system together, if the CO2 were taken in by the photosynthesis of plant, the equilibriums of fig.1 would moves to left. For keeping equilibrium, many H+ combine HCO3- to form CO2, to compensate the consumption of CO2 of photosynthesis of plant. Thus, the concentration of H+ decreases and the pH value increases. Since there is the equation of (7), with the concentration of CO2 decrease and the pH value increase, the concentration of CO32- increases. With the concentration of CO32- increase, when the K/spcarbonate<CCa2+( Mg2+)(T)×CCO32-(T), the carbonatite sediment occurs, until the K/spcarbonate=CCa2+( Mg2+)(T)×CCO32-(T). So, we can say that, with the help of weathering, the photosynthesis of plant gradually made the CO2 of the atmosphere becoming the carbonatite and was returned into the lithosphere.

If the silicic system and the carbonic system can keep the equilibrium of the concentration of H+ in the seawater, and if the concentration of HCO3- in the seawater is big enough, there would be the equation as follow:

 

                                 

The 1 molecular organic matter (CH2O) is formed by photosynthesis, the 1 molecular O2 is produced and the 1 molecular CO2 is fixed. Simply, formation of 1 molecular (CH2O) by photosynthesis of plants would fix 1 molecular CO2. According to formula (18), consumption of 1 molecular CO2 would form 1 molecular CaCO3 or MgCO3. That is to say, formation of 1 molecular (CH2O) by photosynthesis of plant, would lead to sediment of 1 molecular CaCO3 or MgCO3.

The molecular weight of organic matter (CH2O) is 30, the average molecular weight of carbonatite is 92.15. So, to form the 6×107Gt(1Gt=109t) of sedimentary carbonatite[16], the quantity of organic matter that the photosynthesis of plant will to produce is 6×107Gt×30÷92.15=1.95×107Gt. That is to say, when the silicic system and the carbonic system can keep the equilibrium of the concentration of H+ of the seawater, if the photosynthesis of plant synthesizing 1.95×107Gt organic matter, can form all the sediment carbonatite in the earth.

The 80-90% of the sedimentary organic matter, the mineral organic matter, is mainly the kerogen[18]. The kerogen has three kinds, the , and [19-21]. The kerogen evolved from the CH2O originally; finally, it maybe becomes the bitumen. The evolution process of kerogen is Ⅰ→Ⅱ →Ⅲ. The is close to CH2O, the   is close to bitumen. The H/C of CH2O is 2; the H/C of of kerogen is 1.25-1.75, the H/C of of kerogen is 0.65-1.25, the H/C of of kerogen is 0.46-0.93. So the kerogen evolution is the process of utilizing its structural oxygen to oxygenate its carbon and hydrogen, and releasing O and H in the form of CO2 and H2O [19, 22]. That is to say, the process that the CH2O become kerogen is the process of CH2O releasing O and H. The equation is as follow:

n(CH2O)= kerogen+xH2O+yCO2                                    (20)

The Kerogen has a non-stoichiometric and variable composition that depends on its degree of metamorphism. So, for calculating the numbers of how much H2O and CO2 run off from the CH2O when it become the kerogen, we take their average value of quality percentage of all kerogens as the value of kerogen’s C, H and O.

According to the elements analyses of 440 Kerogen samples all over the world, kerogen is consisted of C, H, O, S and N. Their average values of quality percentage are: C, 76.4%; H, 6.3% and O, 11.1%. The three elements make up 93.8% of kerogen. So the C, H, O are the main elements of kerogen[18]. The molecular weight of C, H and O are respectively 12, 1 and 16. Based on the average value of quality percentage of kerogen, the average molecular number of C in kerogen is 76.4÷12=6.37; the average molecular number of H in kerogen is 6.3÷1=6.3; the average molecular number of O in kerogen is 11.1÷16=0.69. So, the average molecular ratio of kerogen is C6.4H6.3O0.7. Making the coefficient of C6.4H6.3O0.7 into integer, the average molecular ratio of kerogen is C64H63O7. The simple equation of (20) is as follow

n(CH2O)= C64H63O7+xH2O+yCO2                                     (21)

In (CH2O), the left of the equation, for the atomic number, C=O2C=H. Since the equation is equal, the right of the equation, the C64H63O7+xH2O+yCO2, must has the C=O2C=H. So, here appear equations as follow:

64+y= 7+x+2y                                                      (22)

2×(64+y)=63+2x                                                   (23)

After solving, the result of the equations is

x=44.75, y=12.25, n=76.25. So equation (21) can be written as

76.25(CH2O)= C64H63O7+44.75H2O+12.25CO2                           (24)

The equation (24) show that the 76.25 mol of (CH2O) form 943 g of C64H63O7  and form 12.25 mol of CO2. The CO2 is inorganic carbon. Based on the equation (19), when having respiration, 1 molecular (CH20) is decomposed, 1 molecular CO2 is produced. So we believe that 12.25 mol of (CH2O) are decomposed into 12.25 mol of CO2 in the process that CH2O became kerogen. That is to say, to form 1 mol of kerogen, 76.25-12.25 mol =64 mol of organic matter would be consumed.

The molecular weight of (CH2O) is 30, so forming 1 mol of C64H63O7 would use up 64×30=1920 g of organic matter (CH2O). C64H63O7s molecular weight is 943. The C64H63O7 amounts to 93.8% of kerogen’s quality ratio. So 1g of kerogen is formed, 1920÷943×93.8%g=1.9g of organic matterCH2Owould be consumed.

The sedimentary carbonatite is 6×107Gt(1Gt=109t), the organic carbon sediment is 1.5×107Gt[16]. To forming the all kerogen in the earth, the actual consumption amount of organic matter that is produced by photosynthesis of plant is 1.9×1.5×107Gt=2.85×107Gt.

Based on the equation (18), to form all the sedimentary carbonatite in the earth, the quantity of organic matter that be synthetized by photosynthesis of plant at the some time is 1.95×107Gt. So, the photosynthesis of plant synthetizes 2.85×107Gt-1.95×107Gt=0.9×107Gt of organic matter, to decrease the concentration of CO2 in the atmosphere and to increase pH value in the seawater. In other words, with the help of the weathering, the photosynthesis of plant not only consumes CO2 to form sedimentary carbonatite, but also consumes CO2 to increase the pH value of the seawater.

 

2  The relationship between CO2-greenhouse effect and the glacier formation

With the further study of the global change, the academic circles have an acknowledgment of importance of the effect of greenhouse effect of CO2 on the global climate. A rise of CO2 concentration strengthens the greenhouse effect. Then, the air temperature increases and the glacier melts, vice versa. When temperature of the polar regions and high mountains below 0, the glacier form[7-8].

Generally, CO2 in the atmosphere is mainly produced by the degasification of the earth[23-24]. So CO2 on the earth increases with the passage of time. 2.35 billion years ago, the air consisted almost of CO2 and N2, and the other component belonged to microscale[25]. Between 2.2~2.75 billion years ago, CO2 concentration in atmosphere was about 100 times of today’s[26].

But, instead of increasing, in some periods, CO2 concentration decreases gradually and leads to the glacier formation finally from the Archaeozoic to the present[7-8,24,27]. And what’s the reason for this?

As above paragraphs show, there are two causes of CO2 decreasing: one is photosynthesis of the plant, turning CO2 into organic matter (CH2O) and release O2[17]:

Another is the CO2 becoming carbonatite and returned into the lithosphere. The sediment of carbonatite on the crust of the earth followed the appearance of the earliest green plant in the year of 3.5 billion years ago[28,29] or later[30]. It indicates that the carbonatite depositing is in company with the start of photosynthesis of green plants. That is to say, the photosynthesis brings about the carbonatite depositing directly or indirectly. With the condition of much CO2 and other acidic substances, there is low pH on the surface of the early earth, so it is impossible to produce the carbonatite sediment. Only, with the passage of time, when the actions of silicic system and carbonic system together can keeping the equilibrium of the concentration of H+ of the seawater, and photosynthesis of plant consumed a lot of CO2, increased the pH value to a certain highness, sediment of carbonatite can occur in the seawater.

From the above, change of CO2 results mainly from photosynthesis of green plants directly or indirectly. Through photosynthesis, green plants takes in a lot of CO2 to form a lot of mineral organic matter, makes the concentration of CO2 of the air is very lower. Meanwhile, with the help of weathering, photosynthesis causes a rise of pH value in seawater, makes the CO2 becoming carbonatite sediment, decreases indirectly the concentration of CO2 in the air.

The compensation point for photosynthesis of CO2 is 0.005~0.01% (the point of one kind of plant differ from the other, CO2 concentration of the air at the present is 0.035%)[17], that is to say, only when the concentration of CO2 in the air is lower than 0.005~0.01%, green plants stop absorbing CO2 in the air for photosynthesis. If a great many of green plants take photosynthesis, after a long time, controlling by photosynthesis directly or indirectly, CO2 would goes down and approaches 0.005~0.01%. Once greenhouse effect went down and became very low, the temperature of the air would decrease continuously. When the temperature in the polar regions and high mountains is lower than 0, glacier would occur.

3  process of biotic Evolution

Radiating the energy outward, the temperature of the early earth went down, the earth crust was formed 4.0~3.8 billion years ago[28]. If an entire ocean of water was present as steam, condensation would have begun when the surface temperature fell below the critical point for water, 374, and the primary ocean was formed[31]. These supplied the base conditions for the living things. The protokaryotic(is a heterotrophic organism with anaerobic feature) appeared about 3.8 billion years ago or much earlier. The plant which would take photosynthesis (that is blue-green algae) appeared about 3.5 billion years ago or much earlier[28, 32]. The eucaryote plants that combined with chromosome, cell nucleus and other evolutive cellular inner structure appeared by 2.0-1.9 billion years ago. The unicellular plants of acritarchs had a thrived period by 0.9-0.85 billion to 0.7 billion years ago, and became extinct about 0.6 billion years ago[2832].

Multicellular organism appeared about 0.7-0.6 billion years ago. Meantime, the multicellular differentiation, tissue differentiation, sex differentiation and life cycle of metagenesis appeared. The appearance of metaphyte fossil (multicellular algae) was a little earlier than metazoa fossil of Ediacara[32]. The whole of fossil of Ediacara animal groups found in many places are located on top of the glacial tillite of the end of the Neo-Proterozoic era, the period of 0.58-0.56 billion years ago[32~33]. The fossil of small shell animals appeared by 0.56 billion years ago[28], and the ‘Cambrian explosion’ appeared by 0.544 billion years ago[32-34].

From the Neo-Proterozoic Era to the Silurian period, the multicellular algae evolved and thrived mainly.

After the Silurian period, plant’s landing began. In the Carboniferous, pteridophyte thrived.

From the late of the Permian Period(about 0.25 billion years ago) to the Mesozoic(about 0.25 ~0.05 billion years ago), the gymnosperm thrived quickly[3].

Angiosperm appeared firstly in the earth by the end of early Cretaceous Period. The angiosperm evolved quickly. Finally, it replaced the gymnosperm, ruled the land in the late Cretaceous Period[3].

4  Formation of the Glacial Epoch before the Neo-Proterozoic Era

How many glacial epochs were there before the neo-Proterozoic era (0.9-0.8 billions years ago)? Because of the lack of some relative data, this is still a problem that needs further research to be made. Up to now, just these glaciers have been discovered 2.9-2.7 billion years and 2.4-2.3 billion years ago[35].

The glacial isostasy brings about geological structural movements (such as orogenetic movement and thalassogenic movement), and leads to volcanic eruption and earthquake[36-37]. Based on the data of the structural movements, the volcanic eruption, the earthquakes, the crust movement, the magmatism, the Archaeozoic era have clear stages, such as the Dahomeyan in mid-south Africa 3.0 billion years ago (Chinese called Qianxi movement), the Kenoran movement in the north America shield 2.6~2.4 billion years ago (it has the strongest and the widest influence, Chinese called Fuping movement ).

The earth crust movement of the Proterozoic era includes the Hudsonian movement 2.0-1.9 billion years ago (European called Karolin movement, Chinese called Luliang movement), and the Kunyang movement in the late mid-Proterozoic era[38].

Although the data are not complete, could also be evaluated primarily that maybe there are 5 glacial periods before the Neo-proterozoic era: the glacial periods about 3.5 billion, 2.9-2.7 billion, 2.4-2.3 billion, 1.9-1.7 billion and 1.4-1.2 billion years ago.

The first kind of living thing emerged in the world is probably heterotrophic bacterium. These prokaryotic organisms exist mainly by decomposing the organic matter in the primary ocean. Them decomposed such macromolecules as carbohydrate, fat and protein into small molecules, simple, organic matter, such as low-fatty acid[39]. The second is photosynthetic bacterial organisms. Making use of light energy, them used the organic matter, H2S, sodium thiosulphate as donor of hydrogen to deacidize CO2, synthetized organic matter[31]. Since the emergence of the living things on the earth, about 3.5 billion years ago, CO2 concentration in the air went down. Both the weathering effect that resulted from the silicic system and non- release-O2 photo-synthesis effect hereinbefore together led the pH rise[24,40]. When pH>pHCO2, there would have be a lot of CO2 dissolving to the seawater, then CO2 concentration in the atmosphere rapid descended, and the greenhouse effect descended, too. Finally the glacier was formed. Since new-formed crust with enough fluidity, although the scale of this glacier is small, the formation and melting of the smaller scale glacier would lead to violent geologic movement, bring the volcanic eruption and earthquake[36-37].

The living things, 35 billion years ago, deacidized CO2 mainly using organic matter, H2S, sodium thiosulphate as donor of hydrogen, synthetized oneself organic matter and lived. Once this donor of hydrogen used out, these kinds of living things reduced quickly, and lower temperature is also another reason of this reduction.

So, when the ability of these living things consuming CO2 was weaker than it of degasification produced by the earth, the temperature-drop would stop, the temperature would go up and this glacial epoch would end.

The death of non- release-O2 organisms voided the ecological room for the photosynthesis organisms of blue-green algae and made them emerged.

Both glaciers of 2.9-2.7 billion years ago and 2.4-2.3 billion years ago were mainly resulted from the lush of the photosynthesis organisms of blue-green algae (green plants), and also from the rise of atmospheric O2 and an accompanying decrease in atmospheric CH4[41]. With the drop of temperature in the glacial epoch, their living room were less and less. When their ability of consuming CO2 was weaker than action of the earth degasification, such as volcanic eruption and earthquake, these two glaciers ended.

During the formation of the glacier 2.4-2.3 billion years ago, the accumulation of O2 increased, atmospheric CH4 decreased[41], the living room of living things enlarged, the biomass of liveweight of unit volume water added up and photosynthesis strengthened. So, this glacier is the strongest glacial period, and the temperature is the lowest, since the Archaeozoic era.

The organism that takes metabolism of aerobic respiration needs the concentration of the lowest limited O2 is about 1% of it at present time. About 2.0 billion years ago, paying great effort for more than one billion years, myxophyte raised the content of the atmosphere to 1% of the present’s. In this degree, the content was able to form thinner ozonosphere to shield the whole ultraviolet rays of 250nm. If the water were as deep as 4.2m, it would shield the whole ultraviolet rays. In another word, if the living things are in the water below 4.2m, ozonosphere can save them from damage of ultraviolet rays[42].

Owing to the increasing of O2, the eucaryote cell appeared. Since the effect of this strong glacier, the prokaryotic organism weakened and released the living room for eucaryote cell.

If there are the glacial epochs of 1.9-1.7 and 1.4-1.2 billion years ago, it formed by both blue-green algae and eucaryote cell. When their ability of consuming CO2 was weaker than action of the earth degasification, these two glaciers ended.

5  Formation of the glacial period in Neo-Proterozoic Era

Reaching to 10% of the present’s concentration, the concentration of O3 produced by O2 almost completely shield harmful radiation from ultraviolet rays[42]. Until the neo-proterozoic era from 0.9-0.85 billion years ago to the beginning of the Cambrian period 0.57 billion ago),the concentration of O2 reached to 6%~10% of the present’s[43]. This allowed the eucaryote unicellular algae to make photosynthesis on the surface of the ocean. On the surface of the ocean, the sunshine is strong than undersurface. So, the eucaryote unicellular algae can grow luxuriantly in the ocean. This brought eucaryote unicellular algae luxuriant in neo-proterozoic era.

Unlike before, the neo-proterozoic era has about 2-3 glacial epoches with smaller intervals between it. Since the strong photosynthesis of amounts of eucaryote cell, CO2 concentration results from volcanic eruption and the earthquake reduced in certain short time. With the rising of the concentration of O2, the glacier formed repeatedly brought a change of living room and made the multicellular organisms appearance and evolution.

Perhaps the degasification that is produced during the periods of formation and melting of the glacier had a certain stage. It was weaker at the beginning and stronger later. Up to the greatest glacial period in the neo-proterozoic era, the biomass of the green plants were rich enough, the photosynthesis was strong enough. The effect of degasification owing to volcanic eruption and earthquake formed by small scale glacial isostasy was still weaker than photosynthesis, so continuous temperature lowering and continuous glacial enlarging brought about the greatest glacial epoch in the geologic history.

If the photosynthesis and mineral organic carbon depositing were too strong, the increasing amount of CO2 that produced by the volcanic eruption that owing to glacial isostasy was always less than the amount of CO2 that consumed by photosynthesis, these would bring a true snowball. But the emergence of multicellular organisms 0.7-0.6 billion years ago led to the emergence of multicellular animals[32].That is to say, the phytophage animal that live on algae appeared[32]. Because having no predacity animal, phytophage animals had no it’s enemy and bloomed greatly. With the effect of temperature drop and the prey of phytophage animals together, unicellular algae reduced steeply. Because the volcanic eruption and earthquake became violence gradually latter and unicellular algae reduced steeply, the concentration of CO2 could not keep the balance, the concentration of CO2 increasing sharply. Finally, this greatest glacier ended.

6  Formation of glacial period in the Ordovician

The orogenic movement caused by glaciation before the Ordovician made the land on the earth increase. With the appearance of large part (or more) of land, the shallow waters along the coast (continental shelf) appeared. These supplied the conditions for the benthonic multicellular algae. Meanwhile, the reduction of unicellular algae released the ecological room for the multicellular algae. So, after the neo-Proterozoic era, such multicellular algae as red alga appeared and aroused adaptive radiation[44].

With the influence of unicellular algae reduction gradually, the struggle for existence of the animals living on unicellular algae was sharpening. To release the pressure of the struggle for existence and looking for living space, the animal enlarged their ecological niche as much as possible. After continuous variation and evolution, many organisms that adapted to different ecological niche and with distinct shapes and functions were evolved. Besides phytophage animals, some predacity animals appeared. In different ecological niche, such as the benthic bottom, shallow sea bottom, shallow sea and sea surface (because of enough O2, ozonosphere sheltered most part of ultraviolet rays), appeared different living things. This is what is called “Cambrian explosion”.

Since the very well ecosystem, the quantity of unicellular algae recovered to some degree. multicellular algae, for example, the red alga were able to live in the more deeper sea water to avoid the damage of ultraviolet and to make a photosynthesis. With the photosynthesis of these plant, after 0.2 billion years’ accumulation, the O2 in the atmosphere rose up progressively till 10% of present’s, and the CO2 reduced gradually. At this period, the variety of large benthonic algae, especially large brown alga grew vigorously in the shallow sea water[44], this speeded the reduce of CO2. When CO2 was less enough to supply enough greenhouse effect, it showed that a glacier formed and a glacial epoch was coming again.

Because then the marine ecosystem was more perfect and complex, the glacial epoch in the Ordovician was shorter than in neo-proterozoic era. So was their scale.

Both time or scale of the glacier in the Ordovician was short and smaller, it was possible to be brought about by other benthonic alga besides the bull-kelp. So the glacial epoch might consist of several smaller glacial period.

With the emergence of animals, such as the gastropod and the echinoids that live on bull-kelp[45]these animals built a ecological balance with bull-kelp. This marked the end of this glacier.

After the Ordovician, no more advanced plants appeared in the ocean, which could bring about the formation of glacier. So both the formation of glacier and the glacial epoch aroused by marine plants ended.

7  The formation of the glacial age in the end of Carboniferous

After the glacial epoch of the Neo-proterozoic era, there were plenty of land on the earth owing to thalassogenic and orogenic movements. And the land area enlarged again by glaciation after the glacial epoch of the later Ordovician Period. All these create favorable conditions of organisms landing successfully.

Landing on the land, the living things ought to adapt to the conditions of the land, first of all, water, and then the supporting (because the buoyancy of water is lost).

Consisting of unicellular myxophyte and bacteria mycelium, a combination of unicellular, without abilities of absorbing and keeping water, lichen plants made an attempt of landing, but they ended up with failure.

Because the multicellular plants had the possibility of cellular differentiation, the appearance of multicellular algae assured the landing of plants. Even the cells on the surface of the body died of dryness, the inner cells made the plants live continuously. When they grow in the land, they had stronger ability of keeping water than unicellular, too.

bryophyta is the earliest multicellular plant which landed on land. They were primarily multicellular algae (mainly green alga) living in freshwater marsh. And later, after the water receding, the bryophyta still lived on there. So it became the terrestrial plant.

Instead of root and leaf, bryophyta had only rhizina and leaflets. Being terrestrial plants, bryophyta weren’t used to the dry weather of the land. They were impossible to develop massively, to form much more extensive forest. So they did not arouse glacier just as first land plants did.

Another kind of multicellular landing plant was pteridophyte. They had the differentiation of root, stem and leaf. More primitive trachea and fibre tissue also appeared in their body.

Pteridophyte, because of its root and trachea, overcame the problem of absorbing water. Its trachea and fibre tissue, overcame the problem of conveying water and supporting grand body (ensure the plants to spread freely in the sky, receive sunlight as much as possible, have strong photosynthesis). So, pteridophyte is real terrestrial plant.

Under the effect of glacial isostasy of the later Ordovician Period, a lot of volcanic eruption occurred. After the glacial epoch, CO2 increased and the weather are getting more and more warm and wet. Since there was still fewer animals on the land (there were no plants, no animals), Pteridophyte thrived gradually on the land. During the Devonian Period (409~362 million year ago), there were small scale forest of pteridophyte. During the Carboniferous Period (362~290 million year ago), there were large scale forest of pteridophyte[3].

After glaciations of many great ice ages in the Archaeozoic era, Proterozoic era and the Ordovician Period, the land became very large. Vast forest of pteridophyte covered on the extremely large area of land, this made concentration of CO2 decrease (except pteridophyte, bryophyta and algae plants in the ocean had a certain additional function). When the concentration of CO2 was too low to maintain normal greenhouse effect, it would bring about first glacier by the plants on the land.

The area of the land is far less than the ocean, but the thalassogenic and orogenic movements in the formation process of glacier aroused by pteridophyte imbedded a large scale pteridophyte plants into the crust, such as the formation of coal. This process repeated again and again on the land, so enormous CO2 was turned into organic carbon and was imbedded into the crust. Finally, the large scale glacier formed and the glacial epoch appeared.

The scale of this glacial epoch was just next to it of the grand glacial epoch in the Neo-proterozoic era, but much large than that in the later Ordovician Period. With the undulation of CO2 concentration that is induced by the biotic evolution and forest fire, the secondary fluctuation of glacial formation and melting appeared during the glacial epoch.

Then, what’s the reason of ending this glacial epoch?

Because predators do not completely control the Pteridophyte, the end of this glacial epoch depended only on environmental factor.

Pteridophyte had the differentiations of root, stem and leave, also had bundle of trachea and fibre, and adapted to land conditions well in comparison with bryophyta, but its trachea bundle were more primitive with weaker capacity of conveying water.

The more important reason is that it is sporogony without seed, and it needs water in the process of generation. And its leaf has poor ability of keeping warm and cold-proofing. All these weakness shows that they can live only in warm and damp conditions.

With the continuous reproducing of pteridophyte, CO2 was less and less in the air, and it was colder and colder. The glacier on the polar regions and the mountains were more and more big. The formation and thickness of the ice cap on the polar regions, brought about the formation of the four seasons, which became more and more clear. So, the environment on the land was getting more and more cold and dry. Beyond the tolerance of the dryness and coldness, the pteridophyte degraded gradually from the earth. The time of pteridophyte was over finally.

Only fewer pteridophytes remained after adapting to the dry and cold conditions. They either had subterraneous stem or root to live through the cold winter, or formed cuticula to keep water and protect coldness and were much lower and small than paleo-pteridophytes.

The grand glacier, resulting from pteridophyte, led to produce violent thalassogenic movement. This led to the large-scale volcanic eruption and earthquake, and then send off much CO2. Meanwhile, plenty of pteridophytes died and were decomposed by the bacteria, and then send off much CO2 too. Many animals on the globe breathed and also produced CO2. All these replenish the CO2 to the atmosphere of the earth. After a long time accumulation of CO2, the greenhouse effect of CO2 increased. It was getting warmer and glacier was melting.

The grand glacial epoch caused by pteridophyte declared its end.

8  The formation of the Quaternary glacial epoch

From the later Permian Period (about 250 million years ago) to the Mesozoic Era (about 250~50 million years ago), the gymnosperm thrived swiftly. So the Mesozoic Era is called the Age of gymnosperm[3]. Ginkgo, Cycads and Pine-cypress are the representatives of this era. And new pteridophytes (mainly filicineae), such as cladophlebis, coniperis were very luxuriant, but they only stood the second place. These luxuriant gymnosperms and pteridophytes were the main coal-forming plants. The Mesozoic Era, especially the Jurassic Period (about 208~135 million years ago) was another time of coal-forming just next to the Carboniferous and the Permian Period[3].

The angiosperm appeared in the earth by the later of the early Cretaceous Period. The angiosperm thrived quickly and replaced the gymnosperm holding a leading post on the land in the Later Cretaceous Period, such trees as beech, banian, lily magnolia, maple, oak and walnut[3].

Owing to the photosynthesis, the coal-forming of gymnosperm and pteridophyte, and the luxuriance of gymnosperm and angiosperms together made reduction of CO2 in the air. In this case the glacier of the Quaternary Period formed.

The glacial epoch of the Quaternary Period consisted actually of many small glacial periods and small interglacial periods.

The plants were extremely luxuriant and massive mineral organic carbon was deposited in the Jurassic Period. These consumed a lot of CO2. Maybe the formation of the first small glacial period isn’t later than the Jurassic Period.

Why so many small glacial periods were formed in the Quaternary Period?

The glacial formation of the Quaternary Period is due to pteridophyte (of the early small glacial period), gymnosperm and angiosperm. There were so many of variety of gymnosperms and angiosperms, so the glacial formation had so much frequency.

And what’s the cause of glacier melting in each small glacial period?

Since the ecosystem on the land of Quaternary Period was rather perfect, could perform self-regulation very well, it was impossible that the animals made gymnosperm and angiosperm disappear over large areas.

Except in the early time, the reason that most pteridophytes and Ginkgo vanished owed to the cold, it was also impossible that the weather condition bring large area of gymnosperms and angiosperms vanish, because many gymnosperms and most angiosperms were rather advanced and were able to adapt themselves to the normal change of the weather conditions of the earth.

The real main reason that leads to the vanishment and evolution of the gymnosperm and angiosperm is forest fire. The first forest fire happened in the Carboniferous Period, especially in the ice age or the cold period [46~47]. The forest fire reduced the glacier of the small glacial period [48~49].

All the biotic organic carbon like plants, animals and microorganism, and mineral organic carbon like coal, petroleum and gas on the earth are formed through photosynthesis of the plants[17].

As we know from photosynthesis equation (19), one molecular  (CH2O) is formed, one molecular CO2 and H2O are consumed, in other words, by consuming CO2, the photosynthesis forms not only (CH2O), but also O2. This is the reason that the earth turned from anaerobic atmosphere into oxidation atmosphere.

By photosynthesis, the amount of O2 produced is equal to the amount of CO2 consumed on the earth. From the present technique and data, it is difficult to do accurate calculation for the actual CO2 consumption on the earth.

The proportion of O2 and (CH2O) produced by photosynthesis is 1:1, so we can say that how many mol of CH2O is formed, how many mol of O2 would be formed. The amount of  (CH2O) was, in fact, the total of all biotic organic carbon and mineral organic carbon in the ocean, the land and the crust on the earth. The amount is possible to calculate. According to this calculation, we would know the amount of O2 in the earth. Of course, the amount of O2 in the atmosphere should be the gross of O2 subtracted the both amounts of O2 dissolved into water and consumed by turning the earth from anaerobic condition into oxidation condition.

In the whole glacial epoch of the Quaternary Period, there were organisms everywhere including the ocean, land. So the earth surface everywhere enriched biotic organic carbon (plants, animals and microorganism).

From 3.8 billion ago to the Quaternary Period, in the forms of bodies, excreta, or clastic from the living things, abundant mineral organic carbon was deposited into the crust of the earth. The coal, petroleum and gas were most distinctive, but the most abundant deposit of mineral organic carbon was kerogen.

After the Jurassic Period, both amount of total organic matter on the earth and O2 in the air were rather big. The concentration of O2 was same or excess today’s.

A lush of plants produces abundant O2.Once O2 concentration in the air exceeded today’s, this kind of air would be oxygen-enriched air. In which the ignition point of substance decreases and oxidation speed quickens. Many non-combustibles become combustibles. For a normal example, iron does originally not to burn, if a burning red iron wire is put in the pure oxygen, it burns violently and gives strong light.

After the Jurassic Period, with the continuous coal-forming and the luxuriance of gymnosperm, the oxygen increased. When the oxygen in the air reaches or exceeds the present oxygen concentration, it is easy to bring about the forest fire by natural gas or dried up leaves.

The forest fire adds up the CO2 concentration and lowers down or adjusts the balance of O2 concentration in the air.

After the natural choice and the struggle for existence, those gymnosperms which relatively combustive were slowly eliminated, whereas those with relative fire-resistance was remained[37]. Repeating many times like this, gymnosperms strengthened its ability of fire-resistance, was not easy to catch fire and grew widely.

As a result of the appearance of angiosperm, the plants enhanced their adaptability to the circumstance, the surface vegetation of the earth outspreaded increasingly during the later of the early Cretaceous Period.

And up to the Tertiary Period, such mineral organic carbon as coal, natural gas and petroleum had been forming in the stratum. After the repeated struggles between the forest fires and the plant evolution, it turned out that CO2 concentration were lower and lower, the greenhouse effect weaker and weaker. At last, the biggest glacier of the Quaternary glacial epoch appeared. During the time, since a lot of CO2 turned into O2, it was sure that the CO2 concentration dropped down to the lowest point, whereas the O2 concentration in the highest point.

Since the glaciation, the four seasons became clear in the earth. The spring, summer, autumn, winter four seasons and dry and wet seasons appeared in many places of the earth. Thus in the dry seasons, the forest fires happened frequently, which made CO2 concentration go up and O2 concentration drop down. Up to now, the balance has been controlling between the surface vegetation and the forest fires.

 

Bibliography

1  Qin Dahe., Ren Jiawen. Antarctica Glaciology. Beijing: Science Publishing House. 2001.1-220

2  Reading H G. Sedimentary Environments and Facies [M]. London: Blackwell Scientific Publications, 1978. 518~544

3  Song Chunqing, Zhang Z. C. Basic Geology. Beijing: Higher Education Press. 1996. 272-348

4  Kaufman A L, Knoll A H, Narbonne G M. Isotopes, ice ages, and terminal Proterrozoic earth history. Proc. Natl. Acad. Sci. , 1997,95:6600~6605

5  Williams G E. Possible relation between periodic glaciation and the flexure of the galaxy. Earth planet. Sci. Lett., 1975, 26:361~369

6  Williams G E. Late Precambrian glaciation and the earth’s obliquity. Geol. Mag.,1975,112: 441~465

7  Kirschvink J L. Late Proterozoic low-altitude global glaceation: the snowball Earth [A] .Schopf J W, Klein C. The Proterozoic Biosphere[M]. London: Cambridge University Press,1992.51~52

8  Hoffman P F. The break-up of Rocinia, birth of Gondwana, true polar wander and the snowball Earth[J]. Journal of African Earth Science, 1998,28:17~33

9   Guo Jinbao. Chemical oceanography. Xiamen: Xiamen University Press. 199780-398

10  Stix J., Zapata G., Jose A., et.al. A model of degassing at Galeras Volcano, Colombia, 1988-1993. Geology, 1993, 21: 963-967

11  Signorelli S., Vaggelli G., Romano C. Pre-eruptive volatile (H2O, F, Cl and S) contents of phonolitic magmas feeding the 3550-year old Avellino eruption from Vesuvius, southern Italy. Journal of Volcanology and Geothermal Research, 1999, 93: 237-256

12  Thordarson, T., Self S., Oskarsson N., Hulsebosch T. Sulfur, chlorine, and fluorine degassing and atmospheric loading by the 1783-1784 AD Laki (Skaftar Fires) eruption in Iceland. Bulletin of Volcanology, 1996, 58: 205-225

13  Metrich N., Clocchiatti R., Mosbah M., Chaussidon M. The 1989-1990 activity of Etna magma mingling and ascent of H2O-Cl-S-rich basaltic magma; evidence from melt inclusions. Journal of Volcanology and Geothermal Research, 1993, 59: 131-144

14  Stoiber R. E., Williams S. N., Malinconico L. L., Mount St. Helens, Washington, 1980 volcanic eruption; magmatic gas component during the first 16 days. Science, 1980, 208: 1258-1259

15  Muenow D. W., Graham D. G., Liu N. W. K., Delaney J. R. The abundance of volatiles in Hawaiian tholeiitic submarine basalts. Earth and Planetary Science Letters, 1979, 42: 71-76

16  Falkowski P et al. The global carbon cycle: A test of our knowledge of earth as a system. Science. 2000,290:291-296

17  Cao Zongxun.,Wu Xiangjue.  Plant Phsiology. Beijing: Higher Education Press. 1979. 31~125

18  Durand, B.(ed.).Kerogen—Insoluble organic matter from sedimentary rocks, Paris: Ed. Technip, 1980. 1-519

19  Tissot B. P. Recent advances in petroleum geochemistry applied to hydrocarbon exploration. AAPG Bulletin, 1984,  68: 545-563

20  Hunt J. M. ed. Gilluly J. Petroleum geochemistry and geology. San Francisco: W. H. Freeman and Company. 1979. 1-615

21  Durand B., Espitalie J. Geochemical studies on the organic matter from the Douala Basin (Cameroon); II, Evolution of kerogen. Geochimica et Cosmochimica Acta, 1976, 40: 801-808

22  Waples D. W. ed. Klein G. D. Geochemistry in petroleum exploration. Boston: Int. Hum. Resour. Dev. Corp. 1985. 1-232

23  Ozima M, Podosek F A. Noble gas geochemistry. Cambridge: Cambridge University Press. 1983. 1-36

24  Berner R A et al. The carbonate silicate geochemical cycle and its effect on atmospheric CO2 over the past 100 million years. American Jour Science, 1983, 283: 641-683

25  Krupp R, et al. The Early Precambrian atmosphere and hydrosphere; Thermodynamic constraints from mineral deposits. Econ Geol, 1994,98:1581~1598

26  Rye R, et al. Atmospheric CO2 concentrations before 2.2 billion years ago. Nature, 1995,378:603~605

27  Donnadieu Y, Goddéris Y, Ramstein G, Nédélec A Meert J. A 'snowball Earth' climate triggered by continental break-up through changes in runoff. Nature, 2004, 428:303 - 306 

28  Zhang Jun. Evolution of Living Things. Beijing: Beijing University Press, 1998. 41-99

29  Schopf J. W. Microfossils of the early Archean Apex Chert; new evidence of the antiquity of life. Science, 1993, 260: 640-646

30  Brasier M. D., Green O. R., Jephcoat A. P., Kleppe A. K., Van Kranendonk M. J., Lindsay J. F. Steele A. Grassineau N. V. Questioning the evidence for Earth's oldest fossils. Nature, 2002, 416: 76-81

31  Kasting, J.F. Runaway and moist greenhouse atmospheres and the evolution of Earth and Venus. Icarus 1988, 74: 472-494.

32  Hao Shougang,Ma Xueping, Dong Xiping,Qi Wentong,Zhang Xu. The Origination and Evolution of life---Life in the Earth History. Beijing: High Education Press: 2000. 1-242

33  Conway Morris S. The fossil record and the early evolution of the Metazoa. Nature, 1993,361:219-225

34  Bowring S, Grotzinger J, Isachsen C, et al. Calibrating rates of Early Cambrian Evolution. Science. 1993,261:1293-1298

35  Han Yinwen,Ma Zhengdong. Geochemistry. Beijing: Geology Press. 2003. 303-370

36  MeGuire W J. Changing sea levels and erupting volcanoes: cause and effectGeology Today, 1992, 7:141-144

37  Zielinski G A, Mayewski P A, Meeker L D, et al. A 110,000 yr record of explosive volcanism from the GISP2(Greenland) ice core. Quaternary Research, 1996,45: 109-118

38  He Xilin. A Concise Course on  Histrical Geology. Beijing: Coal Industry Press. 1997. 53~266

39  Chen Mingyao. Cultivation on Food Organisms. Beijing: China Xueye Press. 1995.3-92

40  Hoffman P F, Kaufman A J, Halverson G P. et al. Neoproterozoic snowball earth  Science, 1998, 281: 13421346

41  Pavlov A. A., Kasting J. F., Brown L. L., Rages K. A., Freedman R. Greenhouse warming by CH4 in the atmosphere of early Earth. Journal of Geophysical Research, E, Planets, 2000, 105: 11,981-11,990

42  Wayne R. P. Chemistry of Atmospheres (third edition). Oxford: Oxford University Press. 2000.

43  Canfield D. E., Teske A. Late Proterozoic rise in atmospheric oxygen concentration inferred from phylogenetic and sulphur-isotope studies. Nature, 1996, 382: 127-132

44  Taylor T. N.(ed)Mei Maitang, Du XianMing, Li Zhongming (Translated). An Introduction to Fossil Plant Biology. Beijing:Science Press. 1992, 20~418

45  He Xinyi,Xu Guirong. An Course on Paleobiology. Beijing: Geology Press. 1993Second Edition.89~174

46  Graham J B, Dudley R, Aguilar N M, et al. Implications of the late Palaeozoic oxygen pulse for physiology and evolution. Nature, 1995,375:117-120

47  Berner R A. The rise of plants and their effect on weathering and atmospheric CO2. Science 1997, 276: 544-546

48  Berner R A. Paleozoic atmospheric CO2: Importance of solar radiation and plant evolution. Science, 1993, 261:68-70

49  Holland H D. Origins of breathable air. Nature, 1990, 347: 17

 

 

 

 

______This paper comes from the book, Geoscience principle (Liao, Y. Y. Geoscience principle. Beijing: China Ocean press 2007, 1-245), wrote by yongyan liao. The e-mail of the writer of this book is: rock6783@126.com or liaoyy@gdou.edu.cn



http://blog.sciencenet.cn/blog-3534-15508.html

上一篇:Geological process of glacier
下一篇:地震形成原理

0

发表评论 评论 (1 个评论)

数据加载中...

Archiver|手机版|科学网 ( 京ICP备14006957 )

GMT+8, 2019-10-16 03:20

Powered by ScienceNet.cn

Copyright © 2007- 中国科学报社

返回顶部