A Naprendszer geokémiája
Elemek gyakorisága a Naprendszerben
Honnan tudjuk?
- A Nap (és a többi csillag) spektroszkópos tanulmányozása,
- A meteoritok (aszteroida öv, Mars, Hold, kondrit), továbbá
földi, holdi és marsi kőzetek elemzése,
- Fizika, kémia (elméleti, kisérleti)
- Hogyan kondenzálódtak a teljes Naprendszer szilárd anyagai, a
bolygók, és hogy szórtírozódtak az elemek a Naprendszerben?
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Formation of Universe: 15 billion years
Formation of Galaxy: 11 billion Years
Formation of Solar System: 4.6 billion years
Sun is probably a third generation star
Probably takes 10-100 million years for
planets to form
8 bolygó, 39 hold kb. 50 ezer aszteroida építi fel
Nap m 740x
Our Solar System is Not Typical
• Over 100 extrasolar planets known
• Barely can detect Jupiter-size planets,
don't yet have technology to see small
planets
• Many have very eccentric orbits
• Some have gas giants very close in to
sun ("hot Jupiters")
Kondrit
If the Sun and Solar System formed from the same material at the same time,
we would expect the raw material of the planets to match the composition of
the Sun, minus those elements that would remain as gases. A class of
meteorites called chondrites shows such composition, which are thought to be
the most primitive remaining solar system material. Chondrites are considered
the raw material of the inner Solar System and reflect the bulk composition of
the Earth.
belső bolygók = Nap – gázok = kondrit
Normál kondrit (morzsalékos, összetapadt csomók
aggregátuma, nincs mátrix), a csomók/cseppek
több fázisból állnak.
Normál kondritban kondrumok.
A kondrit összetétele
A kondrit összetétele
A Nap összetétele
A Nap összetétele
The highly volatile
elements H, C, N, O and
noble gases are depleted
in C1 meteorite relative
to the Sun photosphere.
Li is depleted in the
Sun.
Zr
The Sun is basically
H+He, whereas the
Earth is dominated by
O, Si, Mg, Fe, S, Al, Ca.
Much Fe is in core,
leaving rocky earth
dominated by O, Si, Mg.
Elemek a Naprendszerben
Nap+C1 szenes kondrit
Faure, 1998
Kozmikus összetétel?
• A Naprendszer (valójában a Nap) elemi összetétele
 kozmikus (csillag) elemi gyakoriság (Li, Be, B)
• A Naprendszer (valójában a Nap) elemi összetétele gázok = szenes kondrit (Naprendszer ősi állapotát
tükröző meteorit)  Föld (és a többi belső bolygó is)
kondritos összetételű (volt?)
Az anyag körforgása
The cycle of matter between the
interstellar clouds and
stars leads to the evolution of the
chemical composition of the
Universe. Part of the material of
this cycle falls and remains
bound in black dwarf neutron
stars and black holes.
In the Nebular Hypothesis, a cloud of gas and dust
collapsed by gravity begins to spin faster because of
angular momentum conservation.
As the nebula collapses further, local regions begin to
contract gravitationally on their own because of
instabilities in the collapsing, rotating cloud 
condensation Protosun and Protoplanets
The collapsing, spinning nebula begins to flatten into a
rotating pancake.
Heating occurred due to potential energy increase.
Volatilization occurred in the central hotter regions,
casting the volatiles into the outer regions.
Only such elements as (Ca, Al, Th, U), Si, Mg, Fe,
etc. (so-called more refractory elements) remained
in the inner regions.
H, C, N, O forming ice crystals (H2O, methane,
CO2, ammonia, nitrogen) moved into the outer
regions.
Formation of Planets
• Planets formed by accretion of smaller objects = impact
• Very tiny objects hold together by atomic forces
• Objects kilometers across hold together by gravity
• As planets get bigger, gravity gets stronger, impacts get
more violent
• Big impacts throw out ejecta, trap heat
A bolygókeletkezés folyamatának sematikus ábrája az időskálával
A bolygók szilárd magjai porszemcsék összetapadásából keletkeznek
a protoplanetáris korongban. 1/ a gáz és por részecskék szeparációja
 porszemcsék "leülepedése” gravitáció hatására a korong fősíkjában
 a részecske a fősík felé halad összetapad a környező
porszemcsékkel, és így tovább.
Min. 1 km méretű bolygócsírák között gravitációs vonzás lép fel 
ütközés  összetapadás és/vagy aprózódás, azonban az ütközéskor
keletkezett törmelék nem szökik meg, hanem visszahull a felszínre 
eredmény az ún. elszabadult növekedés. (a ~km átmérőjű
populációból véges számú nagyméretű bolygókezdemény alkul ki).
Az oligarchikus növekedés fázisában ezek további, kisebb testeket
abszorbeálnak, amely folyamat végén kialakul kb. néhány száz
protobolygó, amelyek mérete 103-104 km
A földszerű bolygók lassan épülnek fel, további ~108 év alatt, kisebb
tömegű protobolygók összetapadásával, amelyek úgy perturbálják
egymás pályáját, hogy az végül nagy ütközési rátához vezet.
A nagyobb tömegű protobolygók képesek arra, hogy magukhoz
vonzzák a környezetükben található gázt. Ez az akkréció a szilárd
magra nagyon gyors, és nagyon gyorsan véget is ér, mert a gáz
elhasználásával a korongban az óriásbolygó körül egy rés keletkezik a
gravitációs árapály erők miatt.
A továbbiakban a bolygók - akár földtípusúak, akár óriásbolygók számottevően már nem növekednek tömegükben, a bolygókeletkezés
befejeződött, bár az égitestek még néhányszor 108 évig folyamatos
bombázásnak vannak kitéve a kisebb méretű testek,
bolygókezdemények és üstökösmagok által, mint az a Naprendszer
esetében jól ismert.
ELTE, Csillagászati Tanszék
A Nap T-Tauri fázisa
• Sun was initially hotter and bigger than it is
now  the superluminous phase lasted ~10
My and blew off ~25% of it’s mass
• H and He were very abundant, but the solar
wind resulting from this T-Tauri phase blew
most of it out of the solar system
(Változó kistömegű csillag, elemfejlődés C-ig.)
Refrakter (hő-/tűzálló, “makacs”) és
volatil (illó) elemek
(kozmokémiai /kondenzációs ill. illékonyságai/ sajátosság nagy T, kis p)
Refrakter elemek: nagy olvadáspontú, szilárd fázisban  korai
kondezáció a napködből a hűlés során (átmeneti refrakter)
Volatil elemek: kis olvadáspontú, illó fázisban  kis hőmérsékletű
kondenzáció és szublimáció (a napködben nincs folyékony
fázis a kis P miatt) (gyengén, erősen)
ammonia
Kondenzációs sorozat
Anderson, 2007
Fig. 35.8 During condensation of the solar nebula, the protoplanet earth formed by
accretion and differentiation of components, largely on the basis of their different
densities (after Ringwood, 1975). PTA, primitive terrestrial atmosphere.
Wenk Bulakh, 2013
Mineral evolution over earth’s history
In Chapter 34 and earlier in this chapter, we have described the present-day mineral composition of the earth, the moon, and
the planets. We also presented general models on how the first minerals may have formed in the solar system and
subsequently accreted in planets. Looking closer to home, how have minerals evolved during the history of the earth? Much
of the interpretation of the early history of mineral development on earth is based on characteristic isotope data of minerals
found in various classes of meteorites, rocks from the moon, and terrestrial rocks.
As we have seen, the hot solar nebula initially condensed into protoplanets, their satellites, and asteroids. Below 1500 K, in a
turbulently convecting hydrogen silicate atmosphere, many minerals precipitate, including olivine, diopside, feldspar,
enstatite, and metallic iron (Figure 35.8; see also Figure 34.7). In the differentiating earth, the present structure, with core,
mantle and crust, developed during the first 500 million years.
Differentiation occurred on the basis of density and melting point. Volatiles such as hydrogen, helium, sodium, potassium,
lead, mercury, and zinc, with low melting points, accumulated in the outer parts of the earth and were partially swept away by
the solar wind. Iron and other ferrous elements condensed under the force of gravity and started to accrete in the core. At a
later stage, high-temperature silicates and oxides crystallized and accreted as a primitive mantle. Earth minerals have been
forming for the last 4.7 billion years in various stages, the oldest rocks having been dated at 3.8 billion years.
During an early protoplanet stage the list of minerals included about 40--50 species, corresponding largely to minerals in the
oldest metallic meteorites and in primitive chondrites: enstatite, hypersthene, pigeonite, olivine, taenite, kamacite.
At the basalt stage, when the mantle was accreted and started to cool, minerals typical of basaltic magmas began to form in
the earth, as well as on the moon and presumably other planets. The major new mineral species that appeared were feldspars.
The mineralogical composition of this early earth’s mantle corresponded closely to rocks of the moon, particularly:
Major minerals ( > 10%): pyroxenes, plagioclase, olivine, ilmenite
Secondary minerals (1--10%): cristobalite, tridymite, pyroxferroite
At the beginning of the development of the crust there were no more than 200—300 minerals occurring in the earth. Over
time, the environment became more complex; iron—nickel concentrated in the core under gravitational differentiation, the
core and mantle degassed, and water appeared, first as fresh water and later accumulating in saline oceans. In the early stages
there was an oxygen deficiency. Only after the formation of an oxygen-rich atmosphere by photosynthesis did new mineral
species crystallize, most notably iron oxides and hydroxides of the Early Precambrian banded iron formations, as well as
siliceous sediments. Crystallization of feldspars, micas, and quartz would later take place in granitic magmas. Surface
minerals as well as diagenetic alterations added chlorites, serpentine, kaolinite, hematite, carbonates, and halides.
Wenk Bulakh, 2013
Two tendencies are observed in this evolution. First, in similar geological conditions the number of minerals increases from
older to younger rocks. Second, the chemical composition of minerals and their crystal structures becomes more complex
with the evolution of a differentiated crust. Nevertheless, by about the Late Precambrian, most of the minerals that we know
of today probably already existed.
Some of the important mineral-forming environments are summarized in Figure 35.4. The interaction of the convective
mantle and the crust is the source of the major volcanic rocks, either during upwelling at ridges producing basalts, or during
subduction with the formation of island arcs and remelting of andesitic material. Volcanism also occurs at hot spots. In the
USA, alkali basalts in Hawaii and Yellowstone National Park are oceanic and continental examples, respectively.
Plate divergence on continents often produces complex igneous activities, generally with alkaline rocks such as syenites and
carbonatites, as in the Kola Peninsula (Russia), the Rhine Graben (Germany), and the East African Rift.
Mantle convection is also the driving force for tectonic activity and associated metamorphism: convergence of plates may
produce subduction
that results in high-pressure metamorphic rocks such as blueschists (containing glaucophane, jadeite, and aragonite) and
ultimately eclogites (with omphacite and pyrope). Where granites intrude into country rock, contact metamorphism produces
skarns and hydrothermal activity with typical minerals, garnet, vesuvianite, and epidote. During crustal shortening,
overthrusting with regional metamorphism causes amphibolites, gneisses, and marbles to form.
Topographic elevation changes and the influence of water and ice cause original minerals to erode and dissolve; ultimately,
they are transported to more stable settings. These dissolved and retransported minerals form the basis of sedimentary
minerals such as clays, cristobalite--quartz, and calcite, which crystallize in lakes and oceans and are often associated
with organisms. In humid tropical environments, supergene alteration of silicate rocks may occur and transform them to
hydroxides (bauxite, goethite--limonite, manganese minerals) and clays (kaolinite).
Wenk Bulakh, 2013
H miatt reduktív
Anderson, 2007
Kondenzációs
sorozat
Anderson, 2007
Refrakter
Highly
>1300 K
Anderson, 2007
A Föld
A Föld belső övei. A külső merev litoszférát a szilárd, de képlékeny
(„gyenge”) asztenoszféra követi, majd a mezoszféra ismét ridegebb. Az
alatta lévő külső mag folyékony, majd a belső mag – bár kémiai összetétele
hasonló a külső magéhoz - az óriási nyomás miatt szilárd. A litoszférán
belüli kéreg kontinentális és óceáni kéregre tagolható.