The Weathering-Modified Iridium Record of a New Cretaceous—Palaeogene Site at Lechówka Near Chełm, SE Poland, and Its Palaeobiologic Implications

Racki, Grzegorz; Machalski, Marcin; Koeberl, Christian; Harasimiuk, Marian

doi:10.4202/app.2010.0062

Cited by 32 publications

(59 citation statements)

References 49 publications

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“…They reported anomalously high amounts of iridium and other siderophile elements in the strata, consistent with a chondrite meteoritic composition and the Chixculub impact. Mineralogical, as well as geochemical studies presented in this paper confirm the impact origin of the K-Pg boundary clay in Lechówka, as proposed by Racki et al (2011).…”

Section: Introductionsupporting

confidence: 61%

“…The chemostratigraphic profile by Racki et al (2011) shows that the highest concentration of iridium (9.8 ppb) is found in this horizon, c. 10 cm below the boundary clay (Text- fig 2A). Racki et al (2011) explain this as due to intensive circulating of humic, acid-rich ground waters during long-lasting Paleogene weathering under humid conditions, also responsible for the pronounced decalcification; • c. 10 cm thick clay layer with a rusty base with burrows and decalcified opoka clasts.…”

Section: Geological Settingmentioning

confidence: 99%

“…In their description of the Lechówka section, Racki et al (2011) identified eight depositional units; six of them are reported herein. The two lowest units (10 cm thick opoka and a 70 cm thick tectonic/karstic breccia units) are not currently exposed.…”

Section: Geological Settingmentioning

confidence: 99%

“…The two lowest units (10 cm thick opoka and a 70 cm thick tectonic/karstic breccia units) are not currently exposed. Based on Racki et al (2011), the exposed part of the Lechówka succession is as follows (in stratigraphic order) (Text- fig 2A): • 100 cm thick opoka layer with an undulating decalcified top which passes into the overlying sediments; • c. 35 cm thick marly layer with bioturbation at the top.…”

Section: Geological Settingmentioning

confidence: 99%

“…Spherules are usually restricted to the thin impact layer (Smit et al 1992). Racki et al (2011) discovered the first complete record of marine K-Pg boundary deposits in Poland, at the Lechówka Quarry in the south-eastern part of the country. They reported anomalously high amounts of iridium and other siderophile elements in the strata, consistent with a chondrite meteoritic composition and the Chixculub impact.…”

Section: Introductionmentioning

confidence: 99%

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Spherules associated with the cretaceous–paleogene boundary in Poland

Brachaniec¹,

Karwowski²,

Szopa³

2014

Acta Geologica Polonica

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ABSTRACT:Brachaniec, T., Karwowski, Ł. and Szopa, K. 2014. Spherules associated with the Cretaceous-Paleogene boundary in Poland. Acta Geologica Polonica, 64 (1), 99-108. Warszawa.The succession of the Lechówka section near Chełm in south-eastern Poland presents the first complete record of the Cretaceous-Paleogene (K-Pg) boundary in Poland. Samples of the boundary clay were examined for microtektites and shocked minerals to confirm the impact origin of the sediment. The spheroidal fraction reveals morphological and mineralogical features, e.g., spherules, similar to material from the K-Pg boundary as described from elsewhere. The impact genesis of the spherules is confirmed by the presence of nickel-rich spinel grains on their surfaces. The spinels are considered to be primary microlites and, thus, the spherules at Lechówka can be classified as microkrystites. No shocked minerals were noted. The deposits with spherules comprise Aland Mg-rich smectite (Cheto smectite). This almost pure Mg-rich smectite, forming up to 100% of the clay fraction, derived from the weathering of the impact glass. It is proposed that the spherules isolated from the Cretaceous-Paleogene boundary clay at Lechówka come from the Chicxulub crater in Mexico.

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Section: Introductionsupporting

confidence: 61%

Section: Geological Settingmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Spherules associated with the cretaceous–paleogene boundary in Poland

Brachaniec¹,

Karwowski²,

Szopa³

2014

Acta Geologica Polonica

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Ammonites on the Brink of Extinction: Diversity, Abundance, and Ecology of the Order Ammonoidea at the Cretaceous/Paleogene (K/Pg) Boundary

Landman

Goolaerts

Jagt

et al. 2015

Topics in Geobiology

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The Cretaceous-Paleogene (K-Pg) Boundary Site at Lechówka—a New Point on the Geoheritage Map of Southeastern Poland

2019

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A geological section exposed in an abandoned quarry at Lechówka near Chełm represents the most complete record of the Cretaceous-Paleogene (K-Pg) boundary interval in Poland. Here, a thin clay layer with impact ejecta marks the K-Pg boundary, making Lechówka the single place in Poland with a record of the impact that killed off the dinosaurs. Based on the geoheritage evaluation, the Lechówka outcrop represents a content value of rank intermediate between II and III with the iconographic, symbolic, documental and conceptual contents on the local, regional or even global scale. In spite of the obvious scientific and educational importance of the site, its present state is insufficient to attract 'ordinary' geotourists. In order to ameliorate this situation, transformation of the quarry into an officially protected geosite is called for. Only after a formal, technical and infrastructural upgrade of the Lechówka site, combined with popularisation in the media, tourist guidebooks, websites and natural history museums, will it have a chance to become a widely recognised point on the Cretaceous geoheritage map of southeastern Poland. The most important and already well-known localities on this map are the subterranean chalk mines at Chełm, a series of quarries around the mediaeval town of Kazimierz Dolny and a defunct underground phosphorite mine at Annopol, where there are plans for an educational-geotouristic centre.

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The Weathering-Modified Iridium Record of a New Cretaceous—Palaeogene Site at Lechówka Near Chełm, SE Poland, and Its Palaeobiologic Implications

Abstract: In the light of integrated biostratigraphic and geochemical data, a complete shallow−marine succession across the Cretaceous-Palaeogene (K-Pg)

Cited by 32 publications

References 49 publications

Spherules associated with the cretaceous–paleogene boundary in Poland

Spherules associated with the cretaceous–paleogene boundary in Poland

Ammonites on the Brink of Extinction: Diversity, Abundance, and Ecology of the Order Ammonoidea at the Cretaceous/Paleogene (K/Pg) Boundary

The Cretaceous-Paleogene (K-Pg) Boundary Site at Lechówka—a New Point on the Geoheritage Map of Southeastern Poland

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