Principles and Applications of Geochemistry,. 2nd Edition. PAGE Gunter Faure, Prentice-Hall, Upper Saddle. River, N.J., xv + pp., ISBN 5. Principles and applications of geochemistry by Gunter Faure, , Prentice Hall edition, in English - 2nd ed. Principles and Applications of Geochemistry book. Read 4 reviews from the world's largest community for readers. Designed to show readers how to use chem.
|Language:||English, Spanish, Indonesian|
|ePub File Size:||27.65 MB|
|PDF File Size:||9.39 MB|
|Distribution:||Free* [*Regsitration Required]|
Principles and Applications of Geochemistry - Ebook download as PDF File .pdf) , Text File .txt) or read book textbook for geology s tu d en ts/G u n te r Faure. The book starts with basic principles and emphasizes quantitative methods of problem-solving. It uses the principles of isotope geology to enhance the understanding of appropriate geochemical subject areas. The book also examines the geochemical processes that affect the chemical. The second edition of Principles and Applications of Geochemistry demonstrates why this should change. Gunter Faure's book clearly shows.
V enus has a dense atm o sp h e re com posed o f C 0 2 th a t has caused its surface to b ecom e extrem ely h o t and dry. This e q u a tio n is th e n used to explain th e principles and assum ptions o f datin g by th e K -A r. Goldberg Eds. Share full text access. La Geochimie. WestWords, Inc.
Many academic geology departments do not include geochemistry in their undergraduate core curriculums. The second edition of Principles and Applications of Geochemistry demonstrates why this should change.
Gunter Faure's book clearly shows the important role played by quantitative geochemical analysis in our understanding of Earth processes, both natural and anthropogenic.
Beyond its lucid technical explanations, it also includes engaging discussions of the history of geochemistry as a science. Volume 79 , Issue Please check your email for instructions on resetting your password.
If you do not receive an email within 10 minutes, your email address may not be registered, and you may need to create a new Wiley Online Library account. If the address matches an existing account you will receive an email with instructions to retrieve your username.
Journals Earth's Future Open access. Open access. Free Access. First published: Tools Request permission Export citation Add to favorites Track citation. Share Give access Share full text access. Share full text access. Translated by L. Hartsock and A. Pierce, U. Geochemistry for Everyone. Foreign Language Publishing House, Moscow, pp. Mineral Equilibria.
C ertain questions a b o u t o u r existence o n E arth are so fu n d am en tal th a t they h av e b e e n in co rp o ra te d into religious m ythologies. T hese questions n o t only concern th e origin of th e E a rth a n d the evolution of life b u t also extend to th e origin of the universe and to the n a tu re of space and time.
D id th e universe have a beginning a n d will it ever end? W hat existed b efo re th e universe form ed? D oes the universe have lim its an d what exists beyond those limits? It is p ro p e r to raise these questions at th e beginning o f a geo ch em istry course because they are w ithin th e scope of cosm ochem istry. A t first it was not there, and suddenly it fo rm ed and expanded rapidly as though it w ere exploding G o tt, Science has its sh are o f practical jo k ers w ho im m ediately re fe rre d to th e sta rt of th e expansion of th e universe as th e B ig Bang G am ow , F ro m th e very b eg in n in g the universe h ad all of th e m ass and energy it con tains today.
F o rm ation of atom ic nuclei began about This process continued for about 30 m in, but did n o t go beyond helium because the nuclear reac tions could not bridge a gap in the stabilities of th e nuclei of lithium , beryllium , and boron. A t th a t tim e the universe was an intensely h o t and rapidly expanding fireball. Som e , years later, w hen th e te m p e r a tu re had decreased to ab o u t 3 X K, elec tro n s becam e attached to the nuclei of hydrogen and helium.
M atter and radiation w ere thereby sep arated from each other, and th e universe becam e tran sp aren t to light. Subsequently, m a t te r began to be organized into stars, galaxies, and galactic clusters as the universe continued to expand to the present time W einberg, B ut how do we know all this?
In addition, the properties of the universe im m edi ately after the Big Bang w ere sim ilar to those of atom ic nuclei. Therefore, a very fruitful co llab o ra tio n has developed am ong nuclear physicists an d cosm ologists th at has e n a b le d th e m to reco n stru ct the history of the universe back to a b o u t 1CT3 2 sec after the Big Bang.
These studies. Will th e universe c o n tin u e to expand forever? T h e m a tte r th a t is d etectable a t th e p re se n t tim e is n o t sufficient to perm it gravity to o vercom e the expansion.
If expansion continues, th e universe will becom e colder and em ptier w ith n o p ro sp ect of an end. H ow ever, a large fraction of the m ass o f th e universe is h id d en from view in th e form of gas an d dust in interstellar and intergalactic space, and in th e bodies of stars th a t n o longer em it light. In addition, we still cannot rule o u t th e p o s sibility th a t n eutrinos have m ass even w hen they are a t rest. If th e mass of the universe is sufficient to slow th e expansion and ultim ately to rev erse it, th en th e universe will eventually c o n tract until it d isappears again in the stream of time.
Since the universe had a beginning and is still expanding, it can n o t be in fin ite in size. H ow ever, the edge of the universe can n o t be seen w ith telescopes because it tak e s to o long for th e light to reach us.
A s the u n iv erse expands, space expands w ith it. In o th e r w ords, it seem s to be im possible to exceed the physical lim its o f the universe. If o th e r universes exist, we can n o t com m u n i cate with them. Now th a t we have seen th e big picture, let us review certain events in the history of the sta n dard m o d el of cosm ology to show th a t progress in Science is som etim es accidental.
In th e A m erican a stro n o m er E dw in H ub b le re p o rte d th at eighteen galaxies in the Virgo cluster a re receding from E a rth a t d ifferen t rates th a t increase w ith th eir distances from E arth. Shapley at H a rv a rd U niversity. The C ep h eid V ariables are b rig h t stars in th e constellation C epheus w hose p erio d of variation depends on th eir absolute luminosity, w hich is th e to tal rad ian t energy em itted by an astronom ical body.
H u b b le found such variable stars in th e galaxies he was studying an d d e te r m ined th eir absolute lum inosities from th e ir p eri ods. T he intensity o f light em itted by a star decreases as the sq u are of the distance increases.
T herefore, the distance to a star can be d e te r m ined from a com parison of its absolute and its ap p a re n t lum inosity, w here the la tte r is defined as the ra d ia n t p ow er received by the telescope per squ are centim eter. In this way, H u b b le d e te r m ined the recessional velocities and distances of the galaxies in th e Virgo cluster and expressed their relationship as: T he H ub b le co n stan t can be used to place a limit on the age o f th e universe.
If two objects are m oving ap art with velocity v, th e tim e t req u ired for them to becom e sep arated by a distance d is:. This resu lt was very aw kw ard becau se age d eterm in atio n s based o n radioactivi ty had established th a t th e E a rth is o ld er than this date. E v en tu ally W alter B aad e discovered an e rro r in th e calibration of th e C ep h eid Variables, and th e value o f th e H u b b le co n stan t was revised B aad e, This d ate is co m p atib le w ith inde p e n d e n t estim ates o f its age b ased on co nsidera tio n o f nucleosynthesis and th e ev o lu tio n of stars.
T he Big B ang th eo ry of cosm ology was not a ccep ted for m any years fo r a v ariety o f reasons. T he discovery of this rad iatio n was accidental, even th o u g h its existence h ad b e e n predicted tw enty years ea rlie r by G eo rg e G am ow and his colleagues R alp h A.
For exam ple, they noticed th a t tw o pigeons h ad b een nesting in th e th ro a t of th e a n te n n a they w ere using at H o lm del, New Jersey. T h e pigeons w ere caught and tak en to a distan t location, b u t prom ptly retu rn ed. H ow ever, th e intensity of the background radiation rem ained constant and in d ep en d en t of tim e in the course of a year.
W ord o f this p h en o m en o n reached a group of astrophysicists a t n ea rb y P rin ceto n U niversity w ho w ere w orking on m odels of th e early history o f th e universe u n d er th e guidance o f R o b e rt H. D icke.
E ventually, Penzias called D icke, and it. Penzias and W ilson an n o u n ced th e discovery, and D icke and his colleagues explained the cosm ological significance of the m icrow ave background ra d ia tion Penzias and W ilson, In Penzias and W ilson sh ared th e N o b el Prize in physics for their discovery.
The ra d ia tio n discovered by P enzias and W ilson is a rem n an t of the radiation th a t filled the universe for a b o u t , years w hen its tem p e ra tu re was g rea ter th an about K. D uring this early perio d , m a tte r consisted of a m ixture of n u clear particles and p h o tons in th e r m al equilibrium with each other. U n d er these conditions th e energy of radiation at a specific w av elen g th is in v ersely p ro p o rtio n a l to th e absolute te m p e ra tu re.
A ccording to an equ atio n derived by M ax Planck at the start of th e 20th century, the energy of blackbody rad iatio n at a particu lar te m p e ra tu re increases rap id ly with increasing w avelength to a m axim um an d then decreases at longer w avelengths. R ad ia tio n in therm al equilibrium with m a tte r has th e sam e properties as rad iatio n inside a black box w ith opaque walls.
T he w avelength n e a r which m ost of th e energy o f blackbody rad iatio n is con cen trated Amax is approxim ately equal to:. The original m ea su re m e n t of P enzias and W ilson was at a w avelength of 7. The characteristic te m p e ra tu re o f this ra d ia tio n is about 3 K, indicating th a t th e typical w avelength of photons has increased by a factor of a b o u t 1 0 0 0.
O n a subato m ic scale, space betw een stars and galaxies is filled w ith cosm ic rays energetic n u clear particles an d p h o to n s light. Stars are th e basic units in the hierarchy of heavenly bodies w ithin which m atter continues to evolve by nuclear reactions. M any billions of stars are grouped togeth er to form a galaxy, and large num bers o f such galaxies are associated into galac tic clusters.
Stars m ay have stellar com panions or they m ay have orbiting planets, including ghostly com ets th a t flare briefly w hen they approach the star on th e ir eccentric orbits. The planets in our solar system have their own retenue of satellites. The space betw een M ars and Jupiter contains the asteroids, m ost of which are fragm ents of larger bodies th a t have been broken up by collisions and by the gravitational forces of Jupiter and Mars.
Pieces of the asteroids have im pacted as m eteorites on the surfaces of the planets and their satellites and have left a record o f these events in craters. O n a n ev en sm aller scale, space betw een stars contains clouds o f gas an d solid particles. T he gas is com p o sed p rim arily o f hy d ro g en and of helium th a t w ere p ro d u ced durin g th e initial expansion o f th e universe. In addition, th e interstellar m edi u m co n tain s elem en ts o f h ig h er atom ic n u m b er th a t w ere synthesized by n u clear reactions in the interiors o f stars th a t have since exploded.
The evolution o f stars can be described by specifying th e ir lum inosities and surface te m p e ra tures. The lum inosity o f a star is p ro p o rtio n al to its mass, and its surface te m p eratu re or color is an indicator o f its volum e. W hen a cloud o f in terstel lar gas contracts, its tem p e ra tu re increases, and it begins to ra d ia te energy in th e infrared and visible p a rts o f the spectrum.
A s the te m p e ra tu re in the co re of th e gas cloud ap proaches 20 X K, energy p ro d u ctio n by hydrogen fusion becom es possible, and a star is born. M ost o f the stars of a typical galaxy derive energy from this process and th erefo re plot in a band, called the m ain sequence, on the H e rtzsp ru n g -R u ssell diagram show n in Figure 2. M assive stars, called blue giants, have high lum inosities and high surface tem peratures.
Stars th at a re less m assive th a n the S un are called red dwarfs an d p lo t at th e low er en d of th e m ain sequence. A s a star five tim es m o re massive th a n the Sun converts hydrogen to helium while on the m ain sequence, th e density of the core increases, causing th e in te rio r o f th e star to contract. The core te m p eratu re th erefo re rises slowly during the hydrogen-burning phase. This higher te m p e ra tu re accelerates the fusion reaction and causes the o u te r envelope o f th e star to expand.
H ow ever, w hen the core becom es d epleted in hydrogen, the ra te of energy pro d u ctio n declines and the star contracts, raising th e core tem p eratu re still fu r ther. T he site o f energy production now shifts from the core to th e surrounding shell.
The resu lt ing changes in lum inosity an d surface te m p e ra tu re cause the sta r to m ove off the m ain sequence tow ard the realm o f th e red giants Figure 2. T he helium p ro d u c e d by h y drogen fusion in th e shell accum ulates in the core, w hich continues to contract and th e re fo re gets still h o tte r. The resulting expan sio n o f th e env elo p e low ers the surface te m p e ra tu re an d causes th e color to tu rn red.
A t the sam e tim e, th e shell in which hydrogen. When a star has used up the hydrogen in its core, it contracts and then moves off the main sequence and enters the realm of the red giants, which generate energy by helium fusion.
The evolutionary track and the life expectancy of stars are strongly dependent on their masses. Stars five times more massive than the sun are nearly times brighter, have surface temperatures of about Their evolution to the end of the major phase of helium burning takes only about 87 million years Iben, T hese changes tran sfo rm a m ain-sequence star in to a b lo a te d red giant.
F or exam ple, the radius of a sta r five tim es m o re m assive th an the Sun increases a b o u t fold ju st befo re helium bu rn ing in th e core begins. A t the same. The lum inosities and surface tem p era tures color o f red giants becom e increasingly variable as they evolve, reflecting changes in the rates of energy production in the core and shell. T he evolutionary tracks in Figure 2. A star five tim es as m assive as the Sun is times b righter while on th e m ain sequence and has a m ore eventful life as a red giant th a n stars below a b o u t two solar m asses Iben, , N e u tro n stars have very ra p id rates of rotation and em it pulsed radio w aves th a t were first observed in by Jocelyn Bell.
Stars in this configu ratio n have low lum inosities b u t high surface te m p eratu res and are th erefo re called w hite dw arfs Figure 2. In stars of sufficient mass. T he expansion of th e Sun m ay engulf the terrestrial planets. T he Sun. W hen th e fuel fo r a p articu lar energy-producing reactio n is ex h au st ed. T heir gravitational field is so great th at neith er light n o r m atter can escape from them.
Stars w hose m ass is less than ab o u t 1. T he debris from such explosions mixes with hydro gen and helium in interstellar space to form clouds of gas and dust from which new stars may form. H ans B ethe T he increase in te m p e ra tu re m ay trigger a new set o f nuclear reactions. In general. W hen all o f its n u clear fuel h a s been consum ed. A s stars reach th e end o f their evolution they tu rn into white dwarfs. Stars th at are ap precia bly m ore m assive th an the Sun develop dense cores because o f the synthesis of heavy chem ical elem ents by nuclear reactions.
They form. Tow ard th e end o f the giant stage. They are born. If all this is true. T he ab u n d an ce of the chemical elem ents and th e ir naturally occurring isotopes is the blueprint fo r all th eories of nucleosynthesis. G am ow orga nized a conference in W ashington. Figure 2. N eedless to say. T he abundances of the elem ents having atom ic num bers greater th a n 50 a re very low an d do n o t vary appreciably with increasing atom ic num ber.
The conference stim ulated one attendee. Ten years later. G am ow influenced th e evolution of the th e o ry o f nucleosynthesis in m any o th e r ways. In he p ublished a p a p e r in th e O hio Jo u rnal o f Science an unlikely place for a nuclear astro physics p a p e r on th e buildup of heavy elem ents by n e u tro n c a p tu re and subsequently cham pi o n e d th e id ea th a t the chem ical elem ents were synthesized durin g the first 30 m in after the Big B ang.
T he abundances of the first 50 elem ents d ecrease exponentially. Table 2. In fo rm atio n o n th e abundances of nonvolatile elem ents has com e also from chem ical analyses o f stony m eteorites.
H yd ro g en and helium are by far th e m ost ab u n d an t elem ents in the solar system. B eth e. In the m ids A lpher and G am ow w rote a p a p e r d etailing the origin of the chem ical ele m ents based on th at assum ption.
For this re a son. Anders and Ebihara The data were derived primarily by analysis of carbonaceous chondrite meteorites and by optical spectroscopy of light from the Sun and nearby stars Anders and Ebihara.
M oreover. T he nucleosynthesis m o d el of B 2F H includes eight d ifferen t kinds o f nuclear reactions th a t occur a t specified te m p e ra tu res in th e course of th e evolution o f a star. Several o f these re a c tions m ay ta k e place sim ultaneously in th e cores and o u te r shells of m assive stars. A s a result. C onsequently. T he ab u n d an ce of iro n is n otably higher th a n those of o th e r elem en ts w ith similar ato m ic num bers.
T h e abundances of lithium. Two elem ents. Each reaction of this kind liberates 0. It can th en be reused fo r an o th er revolution of th e C N O cycle. T he p ro to n -p ro to n chain works as follows. In fact. We do not argue with the critic who urges that the stars are not hot enough for this process. This alter native m ode of hydrogen fusion w as discovered by H ans B eth e and is know n as th e C N O cycle: T he critical reaction for helium burning is th e fusion o f three.
T he low reactio n cross section o f th e p ro to n p ro to n chain by which the ancestral stars g e n er a ted energy has been a source of concern to nuclear astrophysicists.
Two nuclei of hydrogen. The deuterium nucleus col lides with anoth er p roton to form the nucleus of helium-3 Q H e plus a gam m a ray y and 5. The positron positively charged electron is annihilated by interacting with a negatively charged electron giving off additional energy of 1.
The designation of atom ic species is presented in C hap ter 6. The end result is th at four hydrogen nuclei fuse to form one nucleus of helium This process results in the synthesis of helium either by the d irect p ro to n -p ro to n chain e q u a tio n s 2.
N evertheless. The core te m p e ra tu re rises tow ard x K. T he entire process can be described by a series of eq uations in which the nuclei of hydrogen and helium are represen ted by th e symbols of the appropriate isotopes see C h ap ter 6.
The m ost im portant of these 2. For example. In o rd e r to m ake this isotope by n eu tro n capture reactions. It takes place during the red giant stage of stellar evolution w hen th e n e u tro n flux is low enough to p erm it the product nucleus to decay b efo re the n ext n eu tro n is added.
T hese n u clear reactio n s th e re fo re cause the en h an ced ab u n d an ce of th e ele m ents in th e iron g ro u p illu strated in Figure 2. These reactions involve the addition of a neutron to the nucleus of an atom to produce an isotope having the same atomic num ber but a large mass num ber. D uring the final stages of the evolution of red giants.
T he heaviest ato m p ro d u ced by th e addition of alpha particles is ggNi.
H elium b urning sustains red giants only for a few tens of m illions o f years o r less. T he trip le-alp h a process is in d eed th e key to th e synthesis of all elem en ts b ey o n d helium. This process th ere fo re is characteristically slow and is th ere fo re re fe rred to as the s-process.
By exam ining Figure 2. W ith increas ing te m p e ra tu re in th e core. A n alternative reaction involving th e addition of a pro to n to the nucleus of gHe has an even smaller chance to succeed because th e product.
T he system of nuclear reactions originally p ro p o se d by B 2F H can acco u n t fo r th e observed abundances of the chemical elem ents in the solar system and in nearby stars.
Se is a proton-rich nuclide that cannot form by either the s-process or the r-process and requires the addition of two protons p-process to stable Ge. The process starts with stable N i. This nuclide is synthesized by th e add itio n of tw o p ro tons to stable G e in th e so-called p-process: The dark squares are stable isotopes. N ucleo synthesis is taking place at the present tim e in the stars of our galaxy and in the stars of other galaxies th roughout the universe.
The main line of the s-process. We have good evidence in the w avelength spectra of light from distant galaxies that the chem ical elem ents we find on E a rth also occur everyw here else in the universe. Why do technetium Tc and promethium Pm lack stable isotopes? Why do the elements of Problem 5 exist on the Earth. Zur Frage the chemical elements. T he universe sta rte d w ith a Big Bang a b o u t 15 X years ago an d has evolved since then in accordance w ith th e laws o f physics. Why is lead Pb more abundant than we might have expected?
Check the abundance of argon Ar and deter mine whether it is greater than expected. Stars are th e basic units in the h ierarchy of heavenly bodies. In th e end. Harvard University Press. T hese reactions progress from fusion of hydrogen and helium to n e u tro n cap tu re an d to o th e r reactions..
References A l p h e r. The abundances of the chem ical elem ents in th e solar system can be explained by th e nuclear reactions th a t energize the stars.
T he relative proportions of th e chemical elem ents in o ther stars are different because local conditions m ay affect th e yields o f th e m any nuclear reactions th at contribute to their synthesis. They gen erate energy by nuclear reactions th a t synthesize o th e r elem ents from prim ordial h y d ro gen and helium. T hey form by co ntraction of clouds of in terstellar gas and d u st until th eir core tem p eratu res are sufficient to cause hydrogen fusion.
If so. Why are elements with even atomic numbers more abundant than their neighbors with odd atomic numbers? How did lithium Li. How has the abundance of hydrogen H in the universe changed since the Big Bang?
Solar-system abun dances of the elements. Stars evolve through pred ictab le stages depending on their m asses and initial compositions. What other elements also lack stable isotopes? The chem ical elem ents we know on E a rth occur th ro u g h o u t th e universe. Evolution o f Stars and Galaxies. Goldberg Eds. The Creation o f the Universe.. Energy production in stars.
Post main sequence evolution of single stars.. New Haven. Short papers of the Fourth International Conference. Synthesis of the elements in stars. Earth Science and Meteoritics. Creation of open universes from de Sitter space. Nuclear astrophysics. Explosive Nucleosynthesis.
New York. The First Three Minutes.. G eochronology. Viking Press. University of Texas Press. Bantam Books. After the supernova. Cosmochronology and Isotope Geology. Reprinted by D over Pub. A consistent age for the universe. Open-File Rept. North-Holland Publ. A measurement of excess antenna temperature at 4.
Yale University Press. Nuclear transformations and the origin of the chemical elements. Stellar evolution: Comparison of theory with observation. Geiss and E. Austin and London. Pulsars and high density physics.
The Realm o f the Nebulae. Ohio J. My early memories of Fritz Houtermans. Som etim es th e process leads to th e fo rm atio n of tw o com p anion stars. T he solid particles congregated in this disk and m ade it sufficiently opaque to absorb infrared radiation. T h e exploration of th e solar system has exp an d ed o u r horizo n and has provided th e basis for com p arativ e planetary geochem istry. T he chem ical composi tion of the solar nebula was given in Chapter 2 Table 2.
C ertain kinds of solid particles that had form ed in th e n eb u la ev ap o rated as the tem pera ture increased in o rd e r to m aintain equilibrium b etw een solids and gases.
In th e beginning th e re was a diffuse m ass of inter 22 stellar gas and dust know n as the solar nebula. A12 0 3. T he hu m an race a p p eared on th e E arth only tw o o r th ree m illion years ago and. These included th e d ev elo p m en t of pressure and tem p e ra tu re gradients an d an increase in the rate of rotation. W e th erefo re n eed to b ecom e acquainted w ith th e new w orlds we m ust ex p lo re b efore we c o n cen trate o u r atte n tio n o n th e conventional geochem istry o f th e E arth.
G eochem istry to d ay n o t only encom passes th e stu d y o f th e co m p o sitio n an d chem ical processes occurring on th e E a rth. C am eron and Pine. The tem per ature in th e cen tral disk th erefo re increased until it ranged from ab o u t K at the center to about 40 K at approxim ately 7.
T he dust cloud was rotating in the sam e sense o f the M ilky Way Galaxy and was acted upon by gravitational. It h ad form ed a b o u t six billion years ago as a result o f th e term inal explosions of ancestral stars. T he satellites o f th e large gaseous p lan ets are of special in terest in this new field of study because som e of th em a re larg er th an our M oon an d have very different chem ical com po sitions and surface featu res th a n th e E arth.
T he d ev elo p m en t o f p ressu re and tem p era ture gradients w ithin the disk caused the first. T he pressure ranged from less than 0.
T he increase in the rate of ro ta tion caused p a rt of the nebula outside of the protosun to form a central disk. Info rm atio n for geochem ical studies o f th e solar system is derived by analysis o f m eteo rites and rock sam ples from th e M o o n an d by rem ote sensing of p lan etary surfaces. C om pared to stars. A s soon as th e m ain m ass of the solar nebu la began to contract.
T he condensation tem p eratu res of various com p o u n d s th at existed in the solar n eb u la are listed in Table 3. Glass Instabilities in the o u te r p a rt o f th e disk resulted in th e fo rm atio n of th e gaseous o u te r planets: All gaseous m atte r in the vicinity of th e Sun was blow n aw ay during this period.
U ranus. S aturn. E a rth. T he initial ra te of evolution of th e solar sys tem was rem ark ab ly fast. Mg 2S i0 4] Na reacts with A 3 and silicates to form feldspar and related minerals. N eptune. The resulting solid bodies. T he condensates accreted to form larg er bodies as a result of selective adhesion cau sed by electrostatic and m agnetic forces.
V enus. T he planetesim als in th e in n e r region of the p lan e ta ry disk subsequently accreted to fo rm the s o -c a lle d e a rth lik e p la n e ts — M ercury. Fe forms FeO.
T h e planetesim als close to the p ro to su n w ere com posed of refracto ry com pounds d o m in ated by oxides and m etallic iron and nickel. A 3. T he tim e re q u ired for the Sun to reach the ignition te m p eratu re for T a b l e 3. The T itiu s-B o d e law was p ublished in by J. T he inner planets M ercury. The rem aining 0. T he inner p lan ets resem b le th e E a rth in chem ical com position and are th e re fo re re fe rred to as the terrestrial o r earthlike planets.
T he T itiu s-B o d e law predicts a v alue o f Equatorial diameter. T h e o u te r p lan ets consist prim arily o f h y drogen an d helium w ith small am ounts o f th e o th e r elem en ts and resem ble the Sun in chem ical com position.
Jet Propulsion Laboratory. The densities and sizes of the planets. B ode. The series is com posed of th e n u m b ers 0. Carr et al. T he o u te r planets Jupiter. Titius of W itten b erg in T he earth lik e p lan ets plus the M o o n and asteroids. P lu to also does n o t conform to th e so-called T itiu s-B o d e law. E vidently. The earthlike planets are very small in relation to the Sun and the gaseous planets of the solar system.. Variation of density of the planets with mean distance from the Sun.
T h e earth lik e planets. Note that the Earth has the highest density among the earthlike planets. M ars 5.
In so far as we know. The planets of the solar system magnified times relative to the distance scale. T he earth lik e planets w ere initially m o lte n becau se o f th e h eat g en erated by the rap id c a p tu re o f th e planetesim als an d because of radioactive heating.
P lanetesim als com posed o f m etallic iro n and oxides a ccreted first to form a core th a t was sub seq u en tly b u rie d by th e planetesim als com posed of silicates. V enus has a dense atm o sp h e re com posed o f C 0 2 th a t has caused its surface to b ecom e extrem ely h o t and dry.
A ctually. V enus and E a rth. A cco rd in g to this scen ario. A chronology of these events in T able 3. The surface o f E a rth cooled rapidly. M ars is in ter m e d ia te in size and has h ad volcanic eruptions in th e n o t-to o -d istan ce geologic past.
M ercury an d th e M oon do n o t have atm o sp h eres partly becau se th ey are to o sm all to re tain gaseous ele m ents of low atom ic n u m b er and th e ir com pounds. T h e w ater and o th e r volatiles deposited on th e E a r th prom ptly ev a p o rated to form a dense atm o sp h ere from w hich w ater ultim ately con den sed as th e surface o f th e E a rth cooled. N e ith e r the E a rth n o r any of th e earth lik e p lan ets ever had atm ospheres com posed of the hydrogen and h eli um of th e solar n eb u la because these gases w ere expelled from the inner region of the so lar system during the T-Tauri stage o f th e Sun.
In spite of th e sim ilarity in size and overall com position of V enus an d E a rth. The large satellites o f Ju p ite r w ere seen by G alileo G alilei on January 7. The presence of a large volum e of w ater on the su r face of E arth perm itted geological processes to o p e ra te and created conditions conducive to th e developm ent and evolution o f life.
Four sm all satellites L ed a. Peale et al. B efore the encounters with the Voyager spacecraft. These satellites. G anym ede.
Io is com posed prim arily of silicate m aterial an d m ay have an iron sulfide core. E u ro p a ap p ears to be com pletely covered by a fro zen o cean km deep. Its surface is com posed of w a te r ice m ixed w ith im pu rities th a t cause it to d a rk e n in color. A pro m in en t featu re on its surface is a very large m ultiringed basin called Valhalla w hose diam eter is nearly km. Callisto ap p aren tly becam e inactive very early in its history p a rtly because th e am ount of h e a t g en erated by tidal friction is less than th at of th e o th e r G alilean satellites.
M asubi. L ysithea. It is d a rk e r in color th a n the oth ers and has a heavily cratered icy crust a b o u t km thick. They are n o t volcanically active at th e p re se n t time. C allisto is the o u term o st of th e G alilean satel lites. Io is clearly th e m o st volcanically active object in th e solar system. M aui. P rom etheus. A second ringed basin n e a r the n o rth pole is called Asgard. T he so-called G alilean satellites Io.
T he icy crust m ay b e u n d erlain by liquid w ater th a t does n o t freeze because o f h e a t g en e ra ted by tidal friction. T he b an d s ap p ear to b e fractures in the crust caused by in ternal tectonic activity and by m e te o rite im pacts. The fra c tu re s w ere su b seq u en tly filled w ith subcrustal w ater th a t froze to form ice dikes.
The surface o f E u ro p a is crisscrossed by a m u ltitude o f curving bands. T he icy crust m ay be underlain by a liquid m antle a b o u t 1 0 0 0 km thick com posed o f w ater.
This p re diction was su p p o rted by im ages sen t back by V oyager 1 on M arch 9. C arm e. M o rab ito et. H im alia. T h e volcanic plum es contain sulfur d ioxide and th e lava flows m ay be com posed of liquid sulfur.
E ventually. Hamblin and Christiansen L ike th e G allilean satellites o f Ju p ite r. Hunt and Moore Greeley It has a d ense atm o sp h ere com p o sed p rin cipally of m ethane. T he satellites of Saturn. W e will m en tio n only T itan. Im ages and rem ote-sensing d ata of th ese satellites w ere received only recen tly during. Amalthea is much smaller than Io but appears to be a silicate object. The Galilean satellites magnified 50 times relative to the distance scale.
Variation of the density of the Galilean satellites of Jupiter with increasing distance from the planet. F or this reason. The decrease in density is caused by increases in the proportion of water relative to silicate material.
A lth o u g h an u n d erstan d in g o f these new w orlds m ust ultim ately be b ased on studies of th e chem ical com positions o f m a tte r an d o f reactio n s and processes th a t tak e place on them. T he ex p lo ratio n of th e new worlds. E xcellent p h o to g rap h s of landform s on p la n e ta ry surfaces a p p e a r in te x t books by H am blin and C hristiansen and by G reeley It shows the roughly circular. Southwest of Mare Crisium is the Mare Fecunditatis.
Photo by NA SA. The Mare Serenitatis is located northwest of Tranquilitatis and extends northwesterly beyond the horizon. The highlands are older than the mare basins and are composed of anorthositic gabbro. The mare basins. Its surface is pockmarked with craters formed by impacts of meteoroids. This view of the Moon was taken from space by the astronauts of Apollo 17 in Decem ber The lunar landscape consists of dark plains.
Armstrong and Edwin E. Aldrin descended from their spacecraft and set foot on the surface of the Moon. The dusty plain in the background contains scattered boulders ejected from craters exca vated by impact of meteoroids. The picture shows Edwin Aldrin on his way down just before he stepped onto the lunar surface. They had landed near the southwest margin of the Sea of Tranquility Mare Tranquilitatis.
Neil A. Photo by NASA.
Mars has an atmosphere composed of N 2 and CO. In some places on Mars the surface is dissected by valleys in dendritic patterns similar to stream valleys on Earth. It also has roughly circu lar plains called planitia and highly cratered highlands resembling those of the Moon. The volcano is km in diameter at its base. The summit contains several overlapping calderas whose presence suggests a long history of volcanic activity. The picture shows the summit of the volcano Olympus Mons protruding through clouds on a frosty morning on Mars much like Mauna Loa on the island of Hawaii.
Mars has been an active planet. Some of the valleys are up to km wide and 7 km deep. The walls of the valleys have been extensively modified by slides and by erosional channels. The rocks into which the valleys are cut are layered and may be sheetlike flows of basalt. As shown. Some of the boulders are pitted or vesicular. The view at the landing site of Viking 2 in the Utopia Planitia is quite similar.
Jupiter is not massive enough to initiate hydrogen fusion in its core. It has a turbulent atmosphere that contains several cyclonic storm centers. It is probably composed of silicate rocks like the Moon and Mars. Photo by N A SA. The surface of Io is not cratered because impact craters are quickly buried by lava flows and volcanic ash.
The heat that causes the volcanic activi ty is generated by tidal forces caused by the gravitational fields of Jupiter and Europa. Unlike Io. Impact craters are present but are not common. The interior of Europa consists of silicate rocks and a small dense core. Europa is encased in a layer of water ice beneath which liquid water may be present. Ganymede and Callisto. CfjHg may form oceans of liquid hydrocarbons.
Because of the low surface temperature on Titan. This satellite is only slightly smaller than Ganymede and has an atmosphere composed mainly of nitrogen with some methane and other hydrocar bon gases. Triton being the most massive. The surface temperature of Triton is only 37 K or. Neptune has at least eight satellites.
This view of the southern hemisphere showing Africa. It is the only planet or satellite with liquid water on its surface and with an atmosphere containing molecular oxygen. Earth is also the only place in the solar system that can sustain life as we know it.
December This and hundreds of other such impact craters testify to the fact that the Earth has been bombarded by meteoroids and comets just as have the Moon. These two lakes form a cir cular structure because they are the remnants of a deeply eroded impact crater. Lawrence River. The chemistry of the solar system. Discovery of currently active extraterres trial volcanism.
Numerical models of the primitive solar nebula. Brown Co. Introduction to Planetary Geology.. T he satellites of Ju p iter form a m in iatu re p lan etary system of th eir own. Earthlike Planets. Moon Planets.
Physics of the primitive solar accre tion disk. The Geology o f the Terrestrial Planets. Melting o f Io by tidal dissipation. Allen and Unwin. Cambridge University Press. Neptune Encounter. Rand McNally. Planetary Landscapes. Voyager Fact Sheet.. T he fo u r largest satellites are sim ilar in size to M ercury and the M oon b u t differ significantly in th e ir chem ical com positions and surface features.
San Francisco. Exploring the Planets. Astronom y and the Origin o f the Earth. T he earth lik e p lan ets co n stitu te a very sm all fraction of the to ta l m ass o f th e solar system an d a re d w arfed ev en by th e o u te r gaseous planets. E a rth is th e only p la n e t in the e n tire solar system o n w hich th e su rface e n v iro n m en t is conducive to the d ev elopm ent and evolu tion of life forms.. The upper m a n tle. T he densities of these m ajo r in terio r units of th e E a rth range fro m 2.
The lower mantle. Figure 4. Table 4. The m antle of the E a rth has b een subdivided into th ree parts based on the presence of b o u n d aries at depths o f and km. T he chem ical co m position o f th e m an tle is difficult to d e te rm in e w ith certain ty because it is inaccessible an d h etero g en eo u s. X enoliths of ultram afic rocks derived from this region indi cate th a t the u p p er m antle is com posed of olivine.
T here are additional. T he increase o f the density an d o f th e velocities o f seismic waves w ith d e p th is caused b o th by changes in th e chem ical com position and by th e recrystal lization of m inerals into m ore closely packed structures.
A lth o u g h som e o f th e o th e r terrestrial planets m ay also h av e rem ain ed active in certain lim ited an d specific ways.
T he resulting intern al stru ctu re of th e E a rth has b e e n d e te rm in e d by seism ologists based on th e reflection and refraction o f compressional P an d sh ear 5 seismic waves. T he cru st-m an tle boundary. The transition zone. O n th e basis of th ese results. The velocity of S waves also increases at the Moho and con tinues to rise with depth in the mantle.
The density of rocks rises abruptly at the Moho and contin ues to increase with depth in the mantle. A third discontinuity in the E-wave velocities within the core marks the transition from the liquid outer core to the solid inner core. S waves do not penetrate the mantle-core boundary. These req u irem en ts are generally satisfied by a rock called p y r o lite inv en ted by R ingw ood by com bining p e rid o tite and basalt in the ra tio of 3.
The core consists of an alloy of Fe. It increases with depth in the man tle but drops sharply again at the m antle-core boundary.
Variation of seis mic velocities with depth in the Earth. The variation of these phys ical properties leads to the con clusion that the mantle is solid and is composed primarily of sili cates and oxides of Mg and Fe. Parker and Taylor and McLennan The g reat in te re st by the scientific com m unity in th e chem ical com position o f th e m an tle an d in th e M oho caused one o f the m o re colorful episodes in th e history o f science.
T he estim ates of th e chem ical com position of the m an tle are com piled in Table 4. Atmosphere — 5. Thus began th e so-called M o hole Project. T hese tests d e m o n strate d th a t it was in d e e d possible to drill in d eep w ater from a ship p o sitio n ed over th e selected site. T he resulting chem ical com position of th e m antle is sim ilar to o n e p ro p o sed by M ason T h e idea ignited th e enthusiastic su p p o rt of the group.
G oldschm idt d ecid ed in th e early s to analyze th e clay-size fractio n of till in so u th ern N orw ay because. We note. T he results in colum ns 1 and 2 of Table 4. C larke and W ashington estim ated the chem ical com position o f th e crust n o t only by averaging a large n u m b e r o f chem ical analyses of igneous rocks from all co n tin en ts and from the ocean basins.
A n en orm ous am o u n t of w ork was req u ired to collect an d analyze th e well over rock sam ples on w hich th e estim ate in colum n 1 is b ased. T he average chem ical com position of 77 sam p les o f glacial clay fro m so u th e rn N orw ay colum n 3. Taylor and M cL en n an. T he stu d y o f th e chem ical com po sition of th e con tin en tal crust. Major Elements T he crust of th e E a rth is im p o rta n t because it con tain s all of th e n a tu ra l reso u rces th a t sustain us.
It includes th e atm osph ere. D aly estim ated its com position by com bining analyses o f granite and basalt in equal proportions colum n 4. Parker H e assigned each region certain lithologic com positions indicat ed in Table 4. Colum n 5 of Table 4. C olum ns 4 -8 of Table 4. These differences arise because the continental crust is com posed prim arily o f granitic rocks granodiorite? Taylor and McLennan Table 3.
P o ldervaart con stru cted a detailed m odel by dividing the crust into the conti nental shields. R onov and Y aroshevsky also m odeled the continental and oceanic crust and arrived at com positions th a t are sim ilar to those of Poldervaart It differs from all o th e r estim ates listed in Table 4.