Resolving impact volatilization and condensation from target rock mixing and hydrothermal overprinting within the Chicxulub impact structure

Déhais, Thomas; Chernonozhkin, Stepan M.; Kaskes, Pim; Graaff, Sietze J. de; Debaille, Vinciane; Vanhaecke, Frank; Claeys, Philippe; Goderis, Steven

doi:10.1016/j.gsf.2022.101410

Cited by 2 publications

(4 citation statements)

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“…Moreover, IODP–ICDP Exp. 364 upper impact melt rock samples have revealed light Cu and Zn isotopic signatures, superimposed on a hydrothermal signal, indicating a possible genetic link with distally ejected K–Pg material, and hinting also toward an enhanced (shock) volatilization and condensation in this unit ( 56 ). These independent data support our results, highlighting the potential of impact melt rock units in carbonate-bearing targets to record and preserve a signature linked to early thermal impact processes such as devolatilization.…”

Section: Discussionmentioning

confidence: 99%

“…well-preserved foraminifera (Fig. S7 ), and based on non-traditional isotopic analysis of the UNAM-7 suevite showing Fe, Cu, and Zn isotope ratios all plotting in the Upper Continental Crust range ( 56 ). Diagenetic fluids cannot explain the T (Δ 47 ) increase of ∼85°C and the ∼5‰ positive shift in δ 18 O between the UNAM-7 lithic breccia and overlying suevite (Figs.…”

Section: Discussionmentioning

confidence: 99%

“…Lastly, two samples from the UNAM-7 drill core outside the outer and likely also exterior ring, at 126 km SE from the center of the Chicxulub structure (Fig. 1 ), are analyzed, which include a suevite and an underlying polymict impact breccia rich (50 in area %) in anhydrite clasts and poor (2.5 in area %) in silicate impact melt particles ( 56 , 59 ).…”

Section: Methodsmentioning

confidence: 99%

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Hot carbonates deep within the Chicxulub impact structure

Kaskes,

Marchegiano,

Peral

et al. 2023

PNAS Nexus

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Constraining the thermodynamic conditions within an impact structure during and after hypervelocity impacts is extremely challenging due to the transient thermal regimes. This work uses carbonate clumped-isotope thermometry to reconstruct absolute temperatures of impact lithologies within and close to the ∼66 Myr old Chicxulub crater (Yucatán, México). We present stable oxygen (δ18O), carbon (δ13C), and clumped-isotope (Δ47) data for carbonate-bearing impact breccias, impact melt rock, and target lithologies from four drill cores on a transect through the Chicxulub structure from the northern peak ring to the southern proximal ejecta blanket. Clumped isotope-derived temperatures (T(Δ47)) are consistently higher than maximum Late Cretaceous sea surface temperatures (35.5°C), except in the case of Paleogene limestones and melt-poor impact breccias outside of the crater, confirming the influence of burial diagenesis and a widespread and long-lived hydrothermal system. The melt-poor breccia unit outside the crater is overlain by melt-rich impact breccia yielding a much higher T(Δ47) of 111 ± 10°C (1 standard error [SE]), which likely traces the thermal processing of carbonate material during ejection. Finally, T(Δ47) up to 327 ± 33°C (1 SE) is determined for the lower suevite and impact melt rock intervals within the crater. The highest temperatures are related to distinct petrological features associated with decarbonation and rapid back-reaction, in which highly reactive CaO recombines with impact-released CO2 to form secondary CaCO3 phases. These observations have important climatic implications for the Cretaceous–Paleogene mass extinction event, as current numerical models likely overestimate the release of CO2 from the Chicxulub impact event.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Hot carbonates deep within the Chicxulub impact structure

Kaskes,

Marchegiano,

Peral

et al. 2023

PNAS Nexus

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“…However, these studies assume that the elemental abundances of siderophile elements (including PGEs) are not significantly fractionated during the impact cratering process which is often not the case. The high thermal energy released during an impact event can change the behavior of the elements and their chemical compounds and in addition, impact‐induced heating can also produce hydrothermal systems that may significantly alter the elemental abundances of the impactites (e.g., Déhais et al., 2022; Koeberl et al., 2012; Naumov, 2002), thus obscuring their presence. One way of bypassing the impact‐related fractionation and/or hydrothermal alteration of the geochemical signatures is the analysis of Cr and Os isotopes.…”

Section: Introductionmentioning

confidence: 99%

Chromium isotopes identify the extraterrestrial component in impactites from Dhala impact structure, India

Anand

Singh

Mezger

et al. 2023

Meteorit & Planetary Scien

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The Dhala structure in north-central India is a confirmed complex impact structure of Paleoproterozoic age. The presence of an extraterrestrial component in impactites from the Dhala structure was recognized by geochemical analyses of highly siderophile elements and Os isotopic compositions; however, the impactor type has remained unidentified. This study uses Cr isotope systematics to identify the type of projectile involved in the formation of the Dhala structure. Unlike the composition of siderophile elements (e.g., Ni, Cr, Co, and platinum group elements) and their inter-element ratios that may get compromised due to the extreme energy generated during an impact, Cr isotopes retain the distinct composition of the impactor. The distinct e 54 Cr value of À0.31 AE 0.09 for a Dhala impact melt breccia sample (D6-57) indicates inheritance from an impactor originating within the non-carbonaceous reservoir, that is, the inner Solar System. Based on the Ni/Cr ratio, Os abundance, and Cr isotopic composition of the samples, the impactor is constrained to be of ureilite type. Binary mixing calculations also indicate contamination of the target rock by 0.1-0.3 wt% of material from a ureilite-like impactor. Together with the previously identified impactors that formed El'gygytgyn, Zhamanshin, and Lonar impact structures, the Cr isotopic compositions of the Dhala impactites argue for a much more diverse source of the objects that collided with the Earth over its geological history than has been supposed previously.

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Resolving impact volatilization and condensation from target rock mixing and hydrothermal overprinting within the Chicxulub impact structure

Cited by 2 publications

References 69 publications

Hot carbonates deep within the Chicxulub impact structure

Hot carbonates deep within the Chicxulub impact structure

Chromium isotopes identify the extraterrestrial component in impactites from Dhala impact structure, India

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