Geology and Magnetic Signatures of the Neugrund Impact Structure, Estonia

Suuroja, Sten; All, Tarmo; Plado, Jüri; Suuroja, Kalle

doi:10.1007/978-3-662-05010-1_11

Cited by 7 publications

(6 citation statements)

References 10 publications

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“…Two-dimensional gravity and magnetic modelling of the uppermost crust (to a depth of 6-9 km) was used to study local structures. Since 1996, attempts have been made to model local basement structures of Estonia (All & Puura 1998;Suuroja et al 2002). The results obtained in the framework of the joint Finnish Crustal Model Program are included in the present paper.…”

Section: Methodsmentioning

confidence: 99%

Orogenic structures of the Precambrian basement of Estonia as revealed from the integrated modelling of the crust

All¹,

Puura²,

Vaher³

2004

Proceedings of the Estonian Academy of Sciences. Geology

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Section: Methodsmentioning

confidence: 99%

Orogenic structures of the Precambrian basement of Estonia as revealed from the integrated modelling of the crust

All¹,

Puura²,

Vaher³

2004

Proceedings of the Estonian Academy of Sciences. Geology

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“…Aeromagnetic data (terrain clearance 300 m, profiles every 500 m, readings every 50 m; Metlitckaya and Papko 1992) over the Neugrund structure show a local negative anomaly. However, the anomaly is about the same wavelength and amplitude (a few hundreds of nT) as the regional NEE‐trending elongated magnetic features, and no clear circular magnetic anomaly can be seen (Suuroja et al. 2002a).…”

Section: Proven Impact Craters Of Estoniamentioning

confidence: 99%

“…This layer is overlain by so‐called Osmussaar Breccias (see below), which are significantly younger and not related to the Neugrund impact. The distal breccia layer (ejecta and tsunami deposits) produced by the Neugrund impact lies within the Early Cambrian Lontova (regional) Stage of greenish‐gray claystone (Suuroja and Suuroja 2000; Suuroja et al. 2002a).…”

Section: Proven Impact Craters Of Estoniamentioning

confidence: 99%

“…This layer is overlain by so-called Osmussaar Breccias (see below), which are significantly younger and not related to the Neugrund impact. The distal breccia layer (ejecta and tsunami deposits) produced by the Neugrund impact lies within the Early Cambrian Lontova (regional) Stage of greenish-gray claystone Suuroja et al 2002a). The stratigraphic age of the distal breccia layer and occurrences of the postimpact succession down to Early Cambrian silt and sandstones (observed by diving into the erosional canyon-like feature (Ring Canyon; Suuroja and Suuroja 2004) between postimpact crater fill and crystalline rim serve as the basis for dating the structure and suggest that it originated by impact into a shallow marine environment.…”

Section: Proven Impact Craters Of Estonia Neugrundmentioning

confidence: 99%

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Meteorite impact craters and possibly impact‐related structures in Estonia

Plado

2012

Meteorit & Planetary Scien

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Abstract-Three structures (Neugrund, Ka¨rdla, and Kaali) of proven impact origin make Estonia the most cratered country in the world by area. In addition, several candidate impact structures exist, waiting for future studies to determine their origin. This article is an overview of these proven and possible impact structures, including some breccia layers. It summarizes the information and descriptions of the morphology; geological characteristics; and mineralogical, chemical, and geophysical data available in the literature. The overview was prepared to make information in many earlier publications in local journals (many of which had been published in Estonian or Russian) accessible to the international community. This review summarizes the facts and observations in a historical fashion, summarizing the current state of knowledge with some additional comments, and providing the references.

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“…535 Ma) Neugrund marine impact structure is an ~20-km-diameter crater with a 5.5-km-diameter central depression located 7 km northeast of Osmussaar Island ( Fig. 1B; Suuroja and Suuroja, 2000;Suuroja et al, 2001). The target rocks consisted of Precambrian metamorphic basement and Vendian-Early Cambrian sand-, silt-, and claystones, covered by ~50 m of water (Suuroja and Suuroja, 2004).…”

Section: Introductionmentioning

confidence: 99%

The mid-Ordovician Osmussaar breccia in Estonia linked to the disruption of the L-chondrite parent body in the asteroid belt

Alwmark¹,

Schmitz²,

Kirsimäe³

2010

Geological Society of America Bulletin

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The Middle Ordovician (466 Ma) Osmussaar breccia, situated along the northwestern coast of Estonia, is rich in angular chromite grains of extraterrestrial origin (>13 grains kg -1 ) and shocked quartz. The angularity of the chromite grains implies that they have not been transported or reworked to any large extent, connoting that the brecciation is the result of a contemporary impactor, either as a direct consequence of the impact or as a result of an earthquake triggered by the impact, and thus is not, as previously suggested, redeposited material from the nearby ~70 m.y. older Neugrund impact structure. The chemical composition of the chromite indicates that the impactor was an ordinary chondrite of L-type, which concurs well with the hypothesis that the infl ux of large bodies to Earth increased during this period due to the breakup of the L-chondrite parent body. This in turn gives support to the recent suggestion that abundant coeval megabreccias worldwide are impact triggered. The presence of extraterrestrial chromite also strengthens the theory that physical pieces of a large celestial body can survive upon impact with Earth. GEOLOGICAL SETTINGThe Osmussaar breccia is an in situ brecciated carbonate section that covers an area of more than 1000 km 2 along the northwestern For permission to copy, contact editing@geosociety.org

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Geology and Magnetic Signatures of the Neugrund Impact Structure, Estonia

Cited by 7 publications

References 10 publications

Orogenic structures of the Precambrian basement of Estonia as revealed from the integrated modelling of the crust

Orogenic structures of the Precambrian basement of Estonia as revealed from the integrated modelling of the crust

Meteorite impact craters and possibly impact‐related structures in Estonia

The mid-Ordovician Osmussaar breccia in Estonia linked to the disruption of the L-chondrite parent body in the asteroid belt

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