The quest for an extraterrestrial component in Muong Nong-type and splash-form Australasian tektites from Laos using highly siderophile elements and Re-Os isotope systematics

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F19%3A00504263" target="_blank" >RIV/67985831:_____/19:00504263 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216208:11310/19:10398310 RIV/00025798:_____/19:00000069

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0016703719301474?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0016703719301474?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.gca.2019.03.009" target="_blank" >10.1016/j.gca.2019.03.009</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The quest for an extraterrestrial component in Muong Nong-type and splash-form Australasian tektites from Laos using highly siderophile elements and Re-Os isotope systematics

Popis výsledku v původním jazyce

Extremely low and variable concentrations of osmium (Os) and other highly siderophile elements (HSE) in most tektites make it challenging to establish direct links between these impact-related materials and their possible extraterrestrial contribution. New Os concentrations (2–43 ppt) and 187 Os/188 Os ratios (0.131–0.68) in a suite of fifteen well-characterized Australasian tektites from Laos (Muong Nong and splash-form types) with variable Ni enrichment indicate a maximum of ∼0.005% addition of a chondritic impactor. This is similar to some Australasian tektites from Vietnam with similarly low siderophile contents, but significantly lower than found in previous studies of more Ni-rich Australasian splash-form tektites and microtektites from different parts of the Australasian strewn field (e.g., Indonesia, South China Sea). The contents of HSE and Re–Os isotopic compositions of layered Muong Nong-type Australasian tektites are highly variable, suggesting mingling of crustal-derived (siderophile element-poor) and extraterrestrial (siderophile element-rich) materials. The absence of a direct correlation between HSE and Ni contents is interpreted to result from a fractionation process related to their different vaporization/condensation temperatures. The low Os abundance in most of the analyzed Australasian tektites, combined with non-radiogenic 187Os/188 Os far below average upper continental crust, may provide a direct test to distinguish continental versus seawater impact scenario. In the absence of any specific low-Os target, a particular process of Os loss following impact is required. We envisage a scenario where evaporative loss of >>90% Os in the form of Os oxides from the overheated tektite melt is aided by volatile species derived from dissociated seawater and/or saline pore water embedded in sediments off-shore Indochina, consistent with elevated contents of halogens in Australasian tektites. This water-assisted Os loss could also play significant role for Central European tektites, while the continental surface with limited amount of water would prevent from more efficient HSE loss as could be the case for Ivory Coast tektites.

Název v anglickém jazyce

The quest for an extraterrestrial component in Muong Nong-type and splash-form Australasian tektites from Laos using highly siderophile elements and Re-Os isotope systematics

Popis výsledku anglicky

Extremely low and variable concentrations of osmium (Os) and other highly siderophile elements (HSE) in most tektites make it challenging to establish direct links between these impact-related materials and their possible extraterrestrial contribution. New Os concentrations (2–43 ppt) and 187 Os/188 Os ratios (0.131–0.68) in a suite of fifteen well-characterized Australasian tektites from Laos (Muong Nong and splash-form types) with variable Ni enrichment indicate a maximum of ∼0.005% addition of a chondritic impactor. This is similar to some Australasian tektites from Vietnam with similarly low siderophile contents, but significantly lower than found in previous studies of more Ni-rich Australasian splash-form tektites and microtektites from different parts of the Australasian strewn field (e.g., Indonesia, South China Sea). The contents of HSE and Re–Os isotopic compositions of layered Muong Nong-type Australasian tektites are highly variable, suggesting mingling of crustal-derived (siderophile element-poor) and extraterrestrial (siderophile element-rich) materials. The absence of a direct correlation between HSE and Ni contents is interpreted to result from a fractionation process related to their different vaporization/condensation temperatures. The low Os abundance in most of the analyzed Australasian tektites, combined with non-radiogenic 187Os/188 Os far below average upper continental crust, may provide a direct test to distinguish continental versus seawater impact scenario. In the absence of any specific low-Os target, a particular process of Os loss following impact is required. We envisage a scenario where evaporative loss of >>90% Os in the form of Os oxides from the overheated tektite melt is aided by volatile species derived from dissociated seawater and/or saline pore water embedded in sediments off-shore Indochina, consistent with elevated contents of halogens in Australasian tektites. This water-assisted Os loss could also play significant role for Central European tektites, while the continental surface with limited amount of water would prevent from more efficient HSE loss as could be the case for Ivory Coast tektites.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GA17-27099S" target="_blank" >GA17-27099S: Variabilita australskoasijských tektitů v širším okolí Muong Nong v Laosu - prostředek k hledání jejich zdrojových hornin a mateřského kráteru</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Geochimica et Cosmochimica Acta

ISSN

0016-7037

e-ISSN

—

Svazek periodika

252

Číslo periodika v rámci svazku

MAY 1 2019

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

11

Strana od-do

179-189

Kód UT WoS článku

000462774200010

EID výsledku v databázi Scopus

2-s2.0-85063053442