The document discusses the post-impact heating of the Boltysh impact crater lake in Ukraine. Key points: 1) Drilling of the Boltysh crater recovered over 600m of lacustrine sediments that filled the crater after impact and provide a record of the early crater lake environment. 2) Palynological analysis of the basal sediments estimates the duration of post-impact heating was 2-5ka, similar to other small craters. 3) Geochemical analysis of the sediments suggests post-impact heating may have lasted longer, around 30-40ka, influenced by the presence of the long-lived crater lake. 4) The prolonged hydrothermal system supported by the lake enhances the

1. Post-impact heating of a crater lake
I. Gilmour1, D.W. Jolley2, J.S. Watson1, M.A. Gilmour1 and S.P. Kelley1
1. Centre for Earth, Planetary, Space and Astronomical Research, The Open University, Milton Keynes MK7 6AA, UK
2. Department of Geology & Petroleum Geology, University of Aberdeen, Aberdeen AB9 2UE, UK

2. Impact hydrothermal systems
• Candidate habitats for the origin and evolution of life
– Mars exploration focused on cratering environments with
evidence of a long-term history of aqueous processes
• Large impact events can generate a hydrothermal
system if the impact occurs on a water- or ice-rich
target
• Potential significance of impact-generated
hydrothermal systems as habitats dependent on
– longevity
– continued availability of liquid H2O and nutrients
– hospitable environments for life in the form of post-impact
lakes and lacustrine sediments

3. Terrestrial impact crater lakes
• Numerous terrestrial impact craters contain lakes and
lacustrine sediments
– Research mainly focused on the paleoclimatic records
• In craters where the lake formed immediately post-
impact, basal lacustrine sediments may have been
altered by the impact-generated heating or hydrothermal
system enabling constraints to be placed on the extent
and duration of heating

4. Boltysh Impact Crater
• 25km complex crater
• Ukrainian Shield – impact on
land
• Ar/Ar age 65.17 ± 0.64 Ma
(Kelley & Gurov, 2002)
• Developed a lacustrine
depositional system in 600 m of
accommodation space
• Pre-dates Chicxulub by a few
ka (Jolley et al. 2010)
• Drilled in the 1960s & 70s
• Cores lost

5. Scien&fic
Drilling,
Spring
2008

6. • 596m
cored
borehole
west
of
central
upli@
• >95%
recovery
• 596
-­‐
582m
–
allochthonous
impact
breccia
• 390m
Cenzoic
crater
fill
• 582
–
490m
cyclic,
fining
upwards,
poorly
sorted
sands
and
sandy
muds
>
turbidity
currents
• 490
–
190m
finely
laminated
organic
rich
shales
• Lacustrine,
abundant
plant
macrofossils
• ~300m
abundant
ostracods
and
gastropods
(in
life
posi&on),
interbedded
with
gypsum
lamellae
>
shallow
evapora&ve
lake

7. (Ames et al., 1998). This is consistent with differences between the
level of alteration within the Kara, Popigai, and Puchezh-Katunki im-
pact structures, Russia (Table 1), where the most intensive impact-
generated hydrothermal alteration took place in the craters that
formed in shallow continental shelf or intra-continental shallow ba-
sins (e.g., Kara and Puchezh-Katunki) (Naumov, 2002). The difference
in the intensity of hydrothermal alteration of crater-fill impactites
and faulted because they represent an interference zone where
inwards-collapsing crater walls interact with the outwar
collapsing edge of the central uplift (Kenkmann and von Dalwi
2000; Osinski and Spray, 2005). Not surprisingly, these zones co
monly represent sites of more intense hydrothermal alterati
particularly the infilling of fractures to form vein networks (Figs
and 2c) (Hode et al., 2003; Osinski et al., 2005). Observations fr
Fig. 1. Distribution of impact-generated hydrothermal alteration deposits within and around a typical complex impact crater. The six settings are highlighted and numbe
in the order in which they are discussed in the text.
G.R. Osinski et al. / Icarus xxx (2012) xxx–xxx
Distribu&on
of
impact-­‐generated
hydrothermal
altera&on
deposits
within
and
around
a
typical
complex
impact
crater
(a@er
Osinski
et
al.
2012)

8. Molecular
parameters
of
cooling
(thermal
matura&on)
Hopane
in
sediment
(geological
configura&on)
ββ22R
βα22R
αβ22R
αβ22S
x
ββ/(αβ+βα+αβ)
βα/(αβ+βα)
Thermal
maturity
parameters

9. 0 5 10
TOC /%
540
546
552
558
564
570
576
582
CoreDepth/m
K/Pg
0.1 0.3 0.5 0.7 0.9
βα/(αβ+βα)0 50100150
B. Braunii
0.1 0.3 0.5 0.7 0.9
ββ/(αβ+βα+ββ)
C31ββ
C31αβ22R
C31βα
C31ββ
C31βα
C31αβ22R
C31αβ22S
C31ββ
C31βα
C31αβ22R
C31αβ22S
15 18 21 24 27
δ18OVSMOW/‰

10. Previous estimates of duration of heating
• ~1.5 – 4.5 ka for the 4 km diameter Kärdla crater (Jõeleht et al., 2005)
• ~5 ka for 24-km-diameter Haughton crater (Parnell et al. 2005)
• 67 ka for 30-km-diameter crater in an early Martian environment (Abramov
and Kring, 2005)
• ~600 ka. and ~1.6 Ma for 23-km-diameter Lappajärvi (Schmieder and
Jourdan, 2013)
• In comparing the longevity of the hydrothermal systems developed at the
Ries and Haughton impact structures, Osinski (2012) concluded that crater
lakes were critical in the development of longer-lived hydrothermal systems
• Continuous sedimentation record at Boltysh in 600 m of accommodation
space provide powerful stratigraphic constraints on timescales

11. Post-impact timescales
• Palynology of early post-
impact sediments
• Early-mid successional
community of ferns and
angiosperms
• Parallels with inter-lava flow
durations
• 2 – 5 ka timescale between
the basal lake sediments
and fern-spike that marks K/
Pg boundary (~581.6 m)
• Need to constrain longer
timescale
CLIMATIC OSCILLATIONS ST
Impactbrecciacraterlaketurbidites
c s f m c
sand
Lithology
576.5
576.7
576.9
577.1
577.3
577.5
577.7
577.9
578.1
578.3
578.5
578.7
578.9
579.1
579.3
579.5
579.7
579.9
580.1
580.3
580.5
580.7
580.9
581.1
581.3
581.5
581.7
581.9
582.1
582.3
582.5
582.7
582.9
583.1
583.3
0 20
C
upressaceae
0 20
Pinaceae
Fagaceae
Thym
elaeaceae
&
undiff
Iacacinaceae
Juglandaceae
M
yricaceae
N
yssaceae
Platanaceae
R
osac
0 20 0 20 0 20 0 20 0 0 0 0 00 20 40
Palm
ae
Gymnosperms Angiosperms - pos
Fig. 2. Frequency plot of selected taxa summed by botanical affinity. These are sh
http://jgs.lyellcollection.org/Downloaded from
5m
Early
Successional
Mid
Successional
Late
Successional

12. -38 -36 -34 -32 -30 -28 -26 -24 -22 -20
δ13Corg (‰)

13. Age Model for Boltysh
Precessional
~178
ka
Obliquity
~340
ka
K
Pg
~250
ka

14. -35 -30 -25 -20
δ13CVPDB/‰
-50
0
50
100
150
200
250
300
350
400
AgerelativetoonsetofCIE/ka
-1 0 1 2 3 4
δ13CVPDB/‰
DSDP 527Boltysh
0 1 2 3
δ13CVPDB/‰
ODP 1049C
0 1 2
δ13CVPDB/‰
DSDP 528
-35 -30 -25 -20 -15
δ13CVPDB /‰
Precession Obliquity
Comparison with marine Dan-C2 hyperthermal record

15. ~30
-­‐
40
kyr

16. Astrobiological Significance
• Impact hydrothermal environments
– Spatial extent
– Continued availability of liquid H2O, energy and nutrients over
extended periods of time
• Majority of Martian impact craters have diameters of less
than 50 km
– many contain well-preserved lacustrine sedimentary deposits
• Boltysh
– no evidence for timescales of heating as long as 600 ka
– estimate of ~30 – 40 ka. is longer than Haughton crater
– Haughton, no evidence preserved for a crater lake forming post-
impact
– Supports the suggestion that the presence an intra-crater lake
may play a crucial role in determining the extent and duration of
impact-induced hydrothermal systems