advertisement

The Boltysh crater fill sediments – a 500,000 year record of the lower Danian

0 %
100 %
advertisement
Information about The Boltysh crater fill sediments – a 500,000 year record of the lower...
Education

Published on March 10, 2014

Author: iaingilmour

Source: slideshare.net

Description

Presented at the Norwegian Network on Impact Research workshop at Gol/Gardos, July 2-7, 2012.
advertisement

The Boltysh crater fill sediments – a 500,000 year record of the lower Danian I. Gilmour1, D.W. Jolley2, R.J. Daly2, S.P. Kelley1, and M.A. Gilmour1 1. Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK 2. Department of Geology & Petroleum Geology, University of Aberdeen, Aberdeen AB9 2UE, UK

The Boltysh crater lacustrine sediments accumulated in around 600m of accommodation space on the Ukrainian shield. The continuity of this accommodation space post-impact would have ensured a continuous record of deposition without the intervals of non-deposition inherent in fluvio-deltaic depositional settings.

Boltysh Impact Crater •  25km complex crater •  Ukrainian Shield – impact on land •  Ar/Ar age 65.17 ± 0.64 Ma (Kelley & Gurov, 2002)

Boltysh Impact Crater •  25km complex crater •  Ukrainian Shield – impact on land •  Ar/Ar age 65.17 ± 0.64 Ma (Kelley & Gurov, 2002) •  Drilled in the 1960s & 70s •  Cores lost

Boltysh Impact Crater •  25km complex crater •  Ukrainian Shield – impact on land •  Ar/Ar age 65.17 ± 0.64 Ma (Kelley & Gurov, 2002) •  Drilled in the 1960s & 70s •  Cores lost •  500m crater-fill sediments central peak Impact melt Cross  sec(on  reconstructed  from  Russian  data  

Boltysh Impact Crater •  25km complex crater •  Ukrainian Shield – impact on land •  Ar/Ar age 65.17 ± 0.64 Ma (Kelley & Gurov, 2002) •  Drilled in the 1960s & 70s •  Cores lost •  500m crater-fill sediments •  Paleogeography n the North-Eastern Peri-Tethys during the Cretaceous Baraboshkin  et  al.,  2003  

Drilled ~12m impact breccia at base of hole

•  596m  cored  borehole  west  of  central  upliA   •  >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  

Palynology Summary •  Palynomorphs – most abundant fossil group •  Good preservation – no thermal alteration/degradation •  Dominated by pollen and spores but include algae •  Early Danian throughout –  Consistent with Cavagnetto and Gaudant (2000) based on IGCP pollen stratigraphic scheme of Meyer (1980) •  Highly diverse palynoflora –  crater marginal –  regional vegetation Ferns   Swamp  cypresses   Normapolles  

Relationship between the Boltysh and Chicxulub Impacts •  Palynological Succession –  Replacement of one floral community with another in a given area •  Supported by δ13CTOC record •  Recovery successions –  Well documented (volcanic) –  K-Pg from Western Interior (US) •  “Fern spike” – an influx of fern spores in post K-Pg sediments •  Phase 1 – warm temperate, subhumid, broadleaved evergreeen •  Phase 2 – leaf, rhizome and cuticles of ferns •  Phase 3 – early successional, high ppt •  Phase 4 – warm temperate, moderately diverse

Location of K/Pg Boundary Jolley,  D.W.,  Gilmour,  I.,  Gurov,  E.P.,  Kelley,  S.P.,  Watson,  J.,  2010.  Geology  38,  835–838.    

Hopane  in  sediment  (biological  configura(on)   Hopane  in  sediment  (geological  configura(on)   ββ22R   βα22R   αβ22R   αβ22S   x

ββ ββ  +  αβ  +  βα Energy   Reac(on  progress   AAer  Seifert  and  Moldowan,  1980)   ββ βα αβ ΔG2   ΔG3   ΔG1   ΔG4   Thermal  maturity  

8.5m   No  ββ  present   ββ  biological   7.1m   ββ  transi(on  

Modelling cooling of impact hydrothermal systems Figure 3. Results of a numerical simulation of the hydrothermal system at a 30-km crater on early Mars. The central peak of the crater is on the left side of each figure. Surface permeability k0 is 10À2 darcies. Solid arrows and dotted arrows indicate the water and steam fluxes, respectively. The lack of arrows in some regions indicates that fluxes are less than 2 orders of magnitude smaller than the maximum flux. Solid lines are isotherms, labeled in degrees Celsius. The length of the arrows scales logarithmically with the flux magnitude, and the maximum value changes with each plot. (a) 25 years, max. water flux = 6.66 Â E12S09 ABRAMOV AND KRING: HYDROTHERMAL ACTIVITY ON EARLY MARS E12S09 Abramov  &  Kring,  2005)  

8.5m   No  ββ  present   ββ  biological   7.1m   ββ  transi(on   ca.  20ka  

Jolley,  D.W.,  Gilmour,  I.,  Gurov,  E.P.,  Kelley,  S.P.,  Watson,  J.,  2010.  Geology  38,  835–838.     <20ka  

Boltysh •  Pre-dates Chicxulub impact –  Establishment of an early successional flora post Boltysh impact implies 5-10ka pre-Chicxulub •  Cooling hydrothermal system –  Timescale for post-Boltysh and Post-Chicxulub recovery •  Rest of core –  550 C-isotope measurements –  Early Danian climate change

Carbon Isotopes •  algal/higher plant input •  Significant CIE 537 – 271m •  Lacustrine δ13Corg •  Selective preservation •  Maturation •  Allochthonous inputs •  Boltysh OM •  Immature sapropellic kerogen •  %C not correlated with δ13Corg •  Reliable indicator of C cycle change K   Pg   -38 -36 -34 -32 -30 -28 -26 -24 -22 -20 δ13Corg (‰) Δδ13C  ~  -­‐3‰   Δδ13C  ~  +4‰     Posi(ve  excursion  

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

Dan-C2 CIE !  Atlantic (Quillévéré et al. (2008) –  Benthic δ13C –  2 excursions !  Tethys (Coccioni et al. (2010) –  Similar to Atlantic X  Pacific (Westerhold et al. 2011) –  No record at Shatsky Rise –  Restricted to Atlantic? !  Continental –  Boltysh lacustrine record –  Global CIE Quillévéré  et  al.  (2008)   Fig. 2. Changes in δ13 C and δ18 O of bulk sediments, CaCO3 content, and magnetic susceptibility (χ) in the lowermost Danian at Contessa Highway, plotted with changes in δ13 C and δ18 O of bulk sediments, CaCO3 content, and magnetic susceptibility from the equivalent stratigraphic interval at ODP Hole 1049C (Black Nose, NW Atlantic) and DSDP Holes 527 and 528 (Walvis Ridge, SE Atlantic), where the Dan-C2 event was first recognized by Quillévéré et al. (2008). Reliable 300R.Coccionietal./EarthandPlanetaryScienceLetters297(2010)298–3 Coccioni  et  al.  2010  

Comparison with Toarcian and PETM CIEs In contrast to the marine Dan-C2 records, the Boltysh record more closely resembles other major CIEs – Isotope stages after Cohen et al. (2007)

CIE Mass Balance McInerney & Wing (2011)

regional and even global ecosystems. A rapid larly forced, end Maastrichtian extinctions across the Fig. 1. Present-day Deccan Trap outcrop extent. Major tectonic structures redrawn from Biswas (1991). Main Deccan Province – from Cripps et al. (2005) •  Final  stages  of  Deccan  –  interac(on  of  basal(c  lavas  and  dykes  with  con(nental  shelf  sediments   •  Evidence  of  interac(on  in  the  Mumbai  area  organic-­‐rich  shales  occur  as  intertrappean  sequences   •  δ13Corg  ~  -­‐26‰     •  Produc(on  of  thermogenic  CH4  from  sedimentary  organic   •  isotopic  frac(ona(on  =  -­‐1.4‰  and  -­‐17.5‰  (Clayton  et  al.  1991)  

in the vitrinit intrusi and M accura tures 900 °C An is that into ho as long ganic m sins w emplac (13) sh geothe thickn and Cesare (1993) contoured for pressures ranging from 100 to 500 MPa. For methane at $375 °C, while fluids in rocks of 5 wt.% TOC are miscible at $2 Calculated densities of the fluid(s) at 100 MPa. At this pressure the CH4-domina while the H2O-dominated phase will have a relatively much higher density of $9 totalKarooBasin westernKarooBasin wt%TOC Area intruded by 100 m thick sill [km2] GenerationpotentialCH4[Gt] 35 000 30 000 25 000 20 000 15 000 10 000 5 000 50 000 250 000 350 000150 000 10 9 8 7 6 5 4 3 2 1 VøringandMøreBasins Fig. 9. Calculated total methane potential in gigatons, (Gt) as a function of area covered by a cumulative intrusion thickness of 100 m continuous sill. The generation potentials are for the western 7017  Gt   150  000  km2   Thermogenic methane from contact metamorphism (Aarnes et al., 2010)

Summary – Boltysh Crater fill sediments •  24km diameter Boltysh Impact Crater in Ukraine –  Lacustrine crater fill sequence of fine grained organic carbon-rich sediments –  Preserve a uniquely complete and detailed negative carbon isotope excursion (CIE) in an expanded section of several hundred metres. •  Position of CIE in the early Danian, ca. 200ka above K/Pg –  Correlates with Dan-C2 CIE in marine record –  Early Danian Hyperthermal Event •  Changes in floral communities through the CIE reflect changing biomes caused by rapidly warming climate, followed by recovery –  EDH event had a similar duration to the Toarcian and Paleocene/Eocene events •  Temporal correlation EDH event with late stages of Deccan Continental Flood basalt province, and initiation of rifting –  Deccan province: cause of global warming and the carbon-isotope excursion •  A high resolution record that is potentially resolving the effect of Chicxulub from the effects of Deccan •  High resolution/stratigraphically complete records have implications…

Add a comment

Related presentations

Related pages

The Geochemistry of the Boltysh Crater Lake Sediments ...

The Geochemistry of the Boltysh Crater Lake Sediments ... Boltysh impact occurred up to 5000 years ... some lower Paleogene ocean sediment records.
Read more

Mabs Ann Gilmour - Publications

... Tethys Ocean a few thousand years before the Cretaceous ... that record early Danian terrestrial ... fill sediments of the Boltysh crater: ...
Read more

Two large meteorite impacts at the Cretaceous-Paleogene ...

Yevgeniy Petrovich Gurov. Yevgeniy Petrovich Gurov. National Academy of Sciences of Ukraine
Read more

Cretaceous–Paleogene boundary - Wikipedia, the free ...

... short time—possibly under ten years. Chicxulub Crater ... the Boltysh crater, ... sank under their own weight as sediment from uplifted ...
Read more

Chicxulub crater - Wikipedia, the free encyclopedia

The Chicxulub crater ... around 66 million years ago. The crater is more than 180 kilometers ... Boltysh crater; Chicxulub crater; Shiva crater;
Read more

What was the nature and role of Normapolles angiosperms? A ...

... the Danian sediments within the Boltysh ... many of the Boltysh Normapolles show ... Data from the Boltysh impact crater records that ...
Read more

Professor Iain Gilmour | OU people profiles

Professor Iain Gilmour, ... nonmarine record of an early Danian hyperthermal ... of the crater-fill sediments from Boltysh impact crater, ...
Read more