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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...
Impact hydrothermal systems
•  Candidate habitats for the origin and evolution of life
–  Mars exploration focused on crat...
Terrestrial impact crater lakes
•  Numerous terrestrial impact craters contain lakes and
lacustrine sediments
–  Research ...
Boltysh Impact Crater
•  25km complex crater
•  Ukrainian Shield – impact on
land
•  Ar/Ar age 65.17 ± 0.64 Ma
(Kelley & G...
Scien&fic	
  Drilling,	
  Spring	
  2008	
  
•  596m	
  cored	
  borehole	
  west	
  of	
  central	
  upli@	
  
•  >95%	
  recovery	
  
•  596	
  -­‐	
  582m	
  –	
  a...
(Ames et al., 1998). This is consistent with differences between the
level of alteration within the Kara, Popigai, and Puc...
Molecular	
  parameters	
  of	
  cooling	
  (thermal	
  matura&on)	
  
Hopane	
  in	
  sediment	
  (geological	
  configura...
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...
Previous estimates of duration of heating
•  ~1.5 – 4.5 ka for the 4 km diameter Kärdla crater (Jõeleht et al., 2005)
•  ~...
Post-impact timescales
•  Palynology of early post-
impact sediments
•  Early-mid successional
community of ferns and
angi...
-38 -36 -34 -32 -30 -28 -26 -24 -22 -20
δ13Corg (‰)
Age Model for Boltysh
Precessional	
  
~178	
  ka	
  
Obliquity	
  
~340	
  ka	
  
K	
  
Pg	
  
~250	
  ka	
  
-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 52...
~30	
  -­‐	
  40	
  kyr	
  
Astrobiological Significance
•  Impact hydrothermal environments
–  Spatial extent
–  Continued availability of liquid H2O...
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Post-impact heating of a crater lake

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Presented at the European Planetary Science Congress, London, 8-13 September 2013

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Post-impact heating of a crater lake

  1. 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. 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. 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. 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. 5. Scien&fic  Drilling,  Spring  2008  
  6. 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. 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. 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. 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. 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. 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. 12. -38 -36 -34 -32 -30 -28 -26 -24 -22 -20 δ13Corg (‰)
  13. 13. Age Model for Boltysh Precessional   ~178  ka   Obliquity   ~340  ka   K   Pg   ~250  ka  
  14. 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. 15. ~30  -­‐  40  kyr  
  16. 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

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