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IMPACT HYDROTHERMAL SYSTEMS, CLAYS, LIFE

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Title: IMPACT HYDROTHERMAL SYSTEMS, CLAYS, LIFE


1
IMPACT HYDROTHERMAL SYSTEMS, CLAYS, LIFE
EXTRATERRESTRIAL ENIVIRONMENTS
K. Kirsimäe, P. Somelar, N.Muttik, A. Jõeleht,
U.Preeden, J.Kirs, J.Plado, J.Kirs, E.Versh etc.
Department of Geology, University of Tartu,
Estonia
2
Who we are ?
... geology is a capital science to begin with,
it needs nothing else but little thinking and
hammering. Ch. Darwin
mineralogy and geochemistry impact induced
hydrotherms numerical modeling
teaching at all levels currently 5 PhD
students
3
Why Impact Hydrothermal Systems (IHT)?
sources of heat and liquid water convection
... IHT systems are suitable niches for
subsurface thermophilic life
4
Impact (Induced) HydroTherms - IHT
Kärdla 4-km
steep thermal gradients temperatures
max 700-800C in shocked rocks without
significant melting 1000-1700C in melt
sheets
Jõeleht et al., 2005
Chicxulub 180-km
Ivanov, 2004
5
Structure of IHT and alteration intensity
very complex structure steep alteration
gradients
S - Z
Chl/S I/S
Ill
S - Z
Chl/S I/S
Chl
Chl-Ep
(Ill?)
vein-type of alteration
heat source magma
6
Why clays ?
hydrated (alumo)silicates with sheet-like
structure that form by alteration of primary
silicates and/or glasses (but not only)
composition, structure and morphology of clay
minerals depends on temperature
fluid composition pH, Eh etc useful for
reconstruction of environmental conditions
CLAY means WATER !!!
... clay mineral surfaces are suggested as
possible sites for prebiotic reactions and
origin of life on Earth
7
Impact (Induced) HydroTherms - IHT
Kärdla 4-km
steep thermal gradients temperatures
max 700-800C in shocked rocks without
significant melting 1000-1700C in melt
sheets
Jõeleht et al., 2005
Chicxulub 180-km
Ivanov, 2004
8
Thermophiles and hyperthermophiles
120º C
HYPERTHERMOPHILES optimal(fastest) growth at 80
120ºC
80º C
THREMOPHILES optimal(fastest) growth at 45 80ºC
T E M P E R A T U R E S C A L E
45º C
Below 45ºC growth inhibited (thermophiles) or
organisms incubated(hyperthermophiles)
Thermophilic aerobic bacteria
9
Liftime of IHT and habitable zones
IHT lifetimes vary from 102- 104 yr for
small craters (eg. Kärdla) and up to 2-3106
yr in for largest structures (eg Sudbury,
Chicxulub) lifetime depends strongly on
the share of convective cooling and rock
permeability
1 yr
70 yr
700
temperature zones suitable for thermophiles
are formed at the outer limits of IHT and
the zone moves inward and deepens under
CP with time
ºC
600
500
1800 yr
400
dead zone
300
200
100
120-80 ºC hyperthermophiles
50
10000 yr
80-45 ºC termophiles
0
10
Liftime of IHT and habitatable zones
Simulated volume of heated rock within the crater
(up to radius 2 km) as a function of time.
11
vein type of alteration
Kärdla rim-wall
12
Stable-isotope composition of IHT carbonate
minerals
13
0
O R G A A N I C S
d13C (PDB)
-10
IHT clacite/dolomite isotope composition
-20
30
20
10
d18O (SMOW)
14
Lappajärvi Chicxulub (Yax-1) Kara Lockne
Popigai Siljan (deep drillcore) Siljan
(surface, shallow dc) Kärdla Neugrund Puchezh-Kat
unki
15
Which of them ?
?
?
?
?
SSUrNA distance tree (Stetter, 1996. FMS M.bio
Rev.)
16
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