The Boltysh crater or Bovtyshka crater is a buried

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...

in the

Kirovohrad Oblast Kirovohrad Oblast ( uk, Кіровоградська область, translit=Kirovohradska oblast; also referred to as #Nomenclature, Kirovohradschyna — uk, Кіровоградщина) is an administrative divisions of Ukraine, oblast (prov ...

Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv ...

,Boltysh at EID
/ref> near the village of Bovtyshka. The crater is in

diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for ...

and its age of 65.39 ± 0.14/0.16 million years, based on argon-argon dating techniques, less than 1 million years younger than

Chicxulub crater The Chicxulub crater () is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is offshore near the community of Chicxulub, after which it is named. It was formed slightly over 66 million years ago when a large a ...

in Mexico and the

Cretaceous–Paleogene boundary The Cretaceous–Paleogene (K–Pg) boundary, formerly known as the Cretaceous–Tertiary (K–T) boundary, is a geological signature, usually a thin band of rock containing much more iridium than other bands. The K–Pg boundary marks the end of ...

(K–Pg boundary). The Chicxulub impact is believed to have caused the

mass extinction An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. It ...

at the end of the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

period, which included the extinction of the non-avian

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s. The Boltysh crater is currently thought to be unrelated to the Chicxulub impact, and to have not generated major global environmental effects.

Overview

Boltysh crater is located in central Ukraine, in the basin of the

Tiasmyn River The Tiasmyn () is a right tributary of the Dnieper River in Ukraine. It is long, and has a drainage basin of .Тясмин

, a tributary of the

Dnieper River } The Dnieper () or Dnipro (); , ; . is one of the major transboundary rivers of Europe, rising in the Valdai Hills near Smolensk, Russia, before flowing through Belarus and Ukraine to the Black Sea. It is the longest river of Ukraine and B ...

. It is in diameter, and is surrounded by an ejecta blanket of

breccia Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of di ...

preserved over an area of . It is estimated that immediately after the impact, ejecta covered an area of to a depth of or greater, and was some deep at the crater rim. The crater contains a central uplift about in diameter, rising about above the base level of the crater. This uplift currently lies beneath about of sediment deposited since the impact, and was discovered in the 1960s during

oil shale Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general composition of oil shales constitute ...

deposits exploration.

Age

The Boltysh depression was identified as a fossil meteorite crater by 1975. By 1987, it was dated to 100 ± 12 million years old. Early age estimates could only be roughly constrained between the age of the impacted rocks (the target) and the age of overlying sediments. The target rocks date from the

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

(98.9 to 93.5 million years ago) and

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by t ...

(93.5 to 89 million years ago) epochs. Bore samples of sediments overlying the crater contain fossils dating from the

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), E ...

epoch, 66 to 54.8 million years ago. The age of the crater was thus constrained to between 54 and 98 million years. Subsequent

radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares t ...

reduced the uncertainty. The concentration of decay products in impact glasses from the crater were used to derive an age of 65.04 ± 1.10 million years. A 2002 analysis of argon radioactive decay products yielded an age of 65.17 ± 0.64 million years. While these radiometric dating measurements place the Boltysh crater hundreds of thousands of years after the Chicxulub crater, a 2010 radiometric and

palynological Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and ''-logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposit ...

study of fern spore (

fern spike In paleontology, a fern spike is the occurrence of unusually high spore abundance of ferns in the fossil record, usually immediately (in a geological sense) after an extinction event. The spikes are believed to represent a large, temporary inc ...

s) abundance suggested the Boltysh impact may have occurred several thousand years before Chicxulub. However, in response, a follow-up study in 2021 estimated using argon–argon dating that Boltysh formed about 65.39 ± 0.14/0.16 million years ago, 650,000 years after the Chicxulub catastrophe, and suggested that the fern spike was plausibly a result of the impact itself. The authors of the paper suggested that the impact may have disrupted recovery after the K/Pg extinction.

Overview

Age

References

Further reading