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

stones with clastic materials occur in the UpperMaastrichtian (50^80 m). It contains rich assem-blages of macrofossils : ammonites Hoploscaphitesconstrictus constrictus (J. Sowerby), H. constrictuscrassus (Lopuski); belemnites Neobelemnella kazi-miroviensis (Skolozdrowna); echinids Cyclaster in-teger Seunes, Echinocorys ciplyensis Lambert,Echinocorys arnaudi Seunes, Echinocorys meudo-nensis Lambert, Echinocorys pyramidata Portlock,Gauthieria radiata broecki Lambert and Salenidiapygmea (von Hagenow). The Upper Maastricht-ian chalk contains very rich assemblages ofbenthic foraminifera. On the basis of their distri-bution the Brotzenella praeacuta Zone (BF12) inthe lower part and Hanzawaia ekblomi Zone

(BF13) in the upper part of the succession wererecognised (Naidin et al., 1984; Beniamovskiiand Kopaevich, 1998; Kopaevich and Benia-movskii, 1999). Planktonic foraminifera assem-blages in the Upper Maastrichtian of Mangyshlakshow a low diversity. However, the presence ofsome zonal species allows to recognise the upperpart of Globotruncanita stuarti Zone and Pseudo-textularia elegans ( = deformis) Zone (Kopaevichand Beniamovskii, 1999). Calcareous nannofossilsinclude Nephrolithus frequens (Gorka), the markerspecies for the Upper Maastrichtian in high lati-tudes (Herman et al., 1988; Naidin et al., 1990;Kopaevich and Beniamovskii, 1999).

Fig. 12. Scheme of the development of the sea/continental conditions in the North-Eastern Peri-Tethys during the Cretaceous(after Baraboshkin, 1997c, changed and completed).

PALAEO 3089 26-6-03

E.Yu. Baraboshkin et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 196 (2003) 177^208 199

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

However, a model was also run without a crater lake to defineits role in hydrothermal activity.

5. Results5.1. Hydrothermal System Mechanics and Lifetimes

5.1.1. The 30-km Crater[35] Results of the numerical simulation of a hydrother-

mal system in a 30-km crater are shown in Figure 3.Overall, this system is driven by a central hot spot, whichheats up water and causes it to rise, generating a single largeupwelling that persists throughout the system’s lifetime. At25 years the system is primarily characterized by a largeregion within the crater’s central peak where temperaturesand pressures are compatible with water’s gaseous phase.

This results in emission of large quantities of steam up tothree kilometers (horizontally) from the center of the crater.Water is drawn toward the crater’s center to replenish theescaping steam. While not modeled explicitly due to thelimitations of the code, this phase transition would have leftbehind minerals and caused a degree of clogging in thisregion. However, subsequent flow of hot water through thecentral peak may have redissolved these minerals. Thesource and sink of the water is the crater lake; virtuallyno water is drawn from the permeable right boundary afterthe formation of the crater lake.[36] By 1,000 years, the steam emission from the central

peak has essentially ceased. While there are still smallquantities of steam being generated within the central peak,it condenses before reaching the surface. The temperatures

Figure 3. Results of a numerical simulation of the hydrothermal system at a 30-km crater on earlyMars. The central peak of the crater is on the left side of each figure. Surface permeability k0 is 10

!2 darcies.Solid arrows and dotted arrows indicate the water and steam fluxes, respectively. The lack of arrows in someregions indicates that fluxes are less than 2 orders of magnitude smaller than the maximum flux. Solid linesare isotherms, labeled in degrees Celsius. The length of the arrows scales logarithmically with the fluxmagnitude, and the maximum value changes with each plot. (a) 25 years, max. water flux = 6.66 "10!5 kg s!1 m!2, max. steam flux = 1.84 " 10!5 kg s!1 m!2; (b) 1,000 years, max. water flux =1.50 " 10!5 kg s!1 m!2, max. steam flux = 2.33 " 10!7 kg s!1 m!2; (c) 10,000 years, max. waterflux = 6.01 " 10!6 kg s!1 m!2; (d) 100,000 years, max. water flux = 8.49 " 10!7 kg s!1 m!2.

E12S09 ABRAMOVAND KRING: HYDROTHERMAL ACTIVITY ON EARLY MARS

8 of 19

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.    

ca.  20ka  

<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 -20δ13Corg (‰)

Δδ13C  ~  -­‐3‰  

Δδ13C  ~  +4‰    

Posi(ve  excursion  

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

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

Quillévére  et  al.  (2008)  

Fig. 2. Changes in δ13C and δ18O of bulk sediments, CaCO3 content, and magnetic susceptibility (χ) in the lowermost Danian at Contessa Highway, plotted with changes in δ13C and δ18O of bulk sediments, CaCO3 content, and magneticsusceptibility 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). Reliablecorrelation of these changes among locations shows the occurrence of the Dan-C2 event, here represented by the lower gray shaded area, at Contessa Highway. The upper gray shaded area marks the “Lower C29n” event. The newbiostratigraphy of the early Danian at Contessa Highway is based on the planktonic foraminiferal (PF) Zones of Berggren and Pearson (2005) and calcareous nannoplankton (CN) Zones of Martini (1971) (1), Romein (1979) (2), Okada andBukry (1980) (3), and Perch-Nielsen (1985) (4). Magnetostratigraphy is from Lowrie et al. (1982). BCL: K–Pg boundary clay layer. Stage and numerical ages (GTS, Geological Time Scale 2004) are from Gradstein et al. (2004).

300R.Coccioniet

al./Earth

andPlanetary

ScienceLetters

297(2010)

298–305

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)

1. Introduction

Continental flood basalt provinces are laterallyextensive lava accumulations of substantial thicknessand low topographic relief (Rampino and Stothers,1988). India’s dominantly tholeiitic Deccan Trapflood basalt province presently extends across approx-imately one sixth of the subcontinent, encompassingup to 106 km2 of its western portion (Deshmukh,1982; Fig. 1). The basalts include Traps downfaultedinto the Arabian Sea west of Mumbai (Bombay) andforming part of the Seychelles microcontinent (Tan-don, 2002; Devey and Stephens, 1991), and possiblyoriginally occupied a volume of up to 106 km3 prior totheir erosion (Courtillot et al., 1986).

The duration of the whole Deccan volcanic episoderemains a polemic issue, and advocates exist for botha brief (b1 m.yrs., e.g., Duncan and Pyle, 1988;Hofmann et al., 2000) and extended (e.g., Widdowsonet al., 2000; Sheth et al., 2001a) period of activity.This theme is particularly pertinent when assessingthe effects of flood basalt volcanism upon local,regional and even global ecosystems. A rapid

emplacement of an entire flood basalt province wouldtheoretically prove more detrimental than a series ofevents separated by protracted dormant intermissions.Proof of quiescent phases exists in the form ofsedimentary sequences that accrued between theTraps. Subsequent extrusives often preserved thesebintertrappeansQ, and evidence can be sought withinthem regarding the influence of volcanism uponsedimentary systems, microclimates and biota.

Because substances released during mafic erup-tions are less likely to reach potentially damagingstratospheric levels than those expelled by felsicvolcanism, the effects of late stage, increasinglyfelsic, explosive Mumbai volcanism are of interest.Controversially, a study of massive, well-constrainedpyroclastic events (Erwin and Vogel, 1992) foundthat these did not reduce the ecological diversities ofland and marine ecosystems on regional or globalscales, and hence were unlikely to be responsible formass extinctions. A bolide impacting Mexico’sChicxulub platform (Hildebrand et al., 1991) isbroadly accepted to have exacerbated, if not singu-larly forced, end Maastrichtian extinctions across the

Fig. 1. Present-day Deccan Trap outcrop extent. Major tectonic structures redrawn from Biswas (1991).

J.A. Cripps et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 216 (2005) 303–332304

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)  

5.2. Aureole thickness

We show that the existing “rule of thumb” predictingaureole thicknesses of about 100% of the sill thicknesscan be improved to involve the temperatures of host-rockand intrusion, in addition to the sill thickness (Eq. (13)).The non-linear response of aureole thickness to sill thick-ness also implies that no universal 1:1 relationship can beexpected, as thicker sills will have relatively thicker normal-ized aureoles. This is due to a longer total time for the heatpulse to pass through the rocks in the case of thicker sills.The derived relationship is consistent with a large diversity

in the data (Fig. 6a and b), and is further supported by avitrinite data showing a relation between the logarithm ofintrusion thickness and the aureole thickness (Raymondand Murchison, 1988). The calculated relationship is lessaccurate for a combination of extreme values in tempera-tures and sill thickness, such as a 1 m sill with T m of900 !C and T hr of 10 !C.

An important implication of the relationship in Eq. (13)is that we expect larger aureoles to occur when sills intrudeinto host-rocks of relatively high background temperatures,as long as the temperature is within the field of normal or-ganic maturation. Thus, thicker aureoles will develop in ba-sins with high geothermal gradients or around deeplyemplaced sills. This is illustrated in Fig. 10a using Eq.(13) showing aureole thicknesses as a function of differentgeothermal gradients. The figure is calculated using a sillthickness of 50 m and a constant intrusion temperature of1150 !C. Fig. 10b illustrates how sill thicknesses influencethe aureole thicknesses with depth. The geothermal gradi-ent is fixed at 20 !C/km, with a constant intrusion temper-ature of 1150 !C. In a volcanic basin, multiple sill intrusionscan cause larger aureoles due to elevated background tem-peratures (Hanson and Barton, 1989; Deyoreo et al., 1991;Aarnes et al., in review-b).

5.3. Composition and fate of fluids

Contact aureoles in shales will be dominated by CH4–H2O fluids rather than H2O–CO2 fluids, because of lowoxygen fugacity resulting from a lack of oxygen sources(Connolly and Cesare, 1993). This fits well with ourassumption of kerogen converting mainly into CH4, ratherthan CO2. At 100 MPa the solubility of CH4 in H2O is 0.4–10 wt.% for the temperature range 100–350 oC (Bonham,1978). This implies that for an aureole with 5 wt.% TOC,

Fig. 8. (a) Fluid speciation phase diagram calculated from Perple_X for a carbon saturated system, using the equation of state from Connollyand Cesare (1993) contoured for pressures ranging from 100 to 500 MPa. For 1 wt.% TOC there will be miscibility between water andmethane at !375 !C, while fluids in rocks of 5 wt.% TOC are miscible at !275 !C, for thermodynamic pressures of 100–200 MPa. (b)Calculated densities of the fluid(s) at 100 MPa. At this pressure the CH4-dominated phase will have a relatively low density of !200 kg/m3,while the H2O-dominated phase will have a relatively much higher density of !900 kg/m3.

tota

l Kar

oo B

asin

west

ern

Karo

o Ba

sin

wt%

TOC

Area intruded by 100 m thick sill [km2]

Gen

erat

ion

pote

ntia

l CH

4 [G

t]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

Vørin

g an

d M

øre

Basi

ns

Fig. 9. Calculated total methane potential in gigatons, (Gt) as afunction of area covered by a cumulative intrusion thickness of100 m continuous sill. The generation potentials are for the westernKaroo Basin (50,000 km2) !400–2100 Gt CH4, the Vøring andMøre basins (85,000 km2) !600–3500 Gt CH4 and the total KarooBasin (390,000 km2) !2700–16,200 Gt CH4, for values of reactedshales from 1 to 6 wt.% TOC.

Gas generation around igneous sills 7189

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…