Alkali differentiation in LL-chondrites

Wlotzka, F.; Palme, H.; Spettel, B.; Wänke, H.; Fredriksson, K.; Noonan, A. F.

doi:10.1016/0016-7037(83)90108-4

Cited by 39 publications

(57 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…LL-chondrites contain twice as much Na as eucrites, and are thus much more prone to such exchange processes. Moreover, as pointed out by Wlotzka et al (1983), this process does not severely affect the sum of Na + K atoms (Rb and Cs are insignificant here). Thus, a negative correlation between Na and the other alkalis should be observed.…”

Section: Origin Of the Unusual Trace Element Patterns Of The High-k Smentioning

confidence: 97%

“…A more complex process has been suggested for the alkali-rich clasts found in the Krähenberg and Bohla LL-chondritic breccias (Wlotzka et al, 1983). These clasts display high enrichments of K (about 10 x), Rb (about 45 x) and Cs (about 70 x) relative to typical LL chondrites, while Na, Sr and Eu are strongly depleted (about 0.5 x), and the REE abundances are normal (except for a pronounced negative Eu anomaly).…”

Section: Origin Of the Unusual Trace Element Patterns Of The High-k Smentioning

confidence: 99%

“…These clasts display high enrichments of K (about 10 x), Rb (about 45 x) and Cs (about 70 x) relative to typical LL chondrites, while Na, Sr and Eu are strongly depleted (about 0.5 x), and the REE abundances are normal (except for a pronounced negative Eu anomaly). Wlotzka et al (1983) proposed that these clasts formed from melts previously enriched in K, Rb, Cs, and that these features occurred as an exchange for Na in feldspars via a vapor phase. Although, these clasts share some unusual features with the high-K glasses found in howardites (e.g., high K/Na ratios), this mechanism is unlikely to be applicable to this study.…”

Section: Origin Of the Unusual Trace Element Patterns Of The High-k Smentioning

confidence: 99%

See 2 more Smart Citations

Trace element geochemistry of K-rich impact spherules from howardites

Barrat

Yamaguchi

Greenwood

et al. 2009

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

The howardite-eucrite-diogenite (HED) achondrites are a group of meteorites that probably originate from the asteroid Vesta. Howardites are complex polymict breccias that sometimes contain, in addition to various rock debris, impact melt glasses which show an impressive range of compositions. In this paper we report on the geochemistry and O isotopes of a series of 6 Saharan polymict breccias (4 howardites and 2 polymict eucrites), and on the trace element abundances of high-K impact spherules found in two of them, Northwest Africa (NWA) 1664 and 1769, which are likely paired.The high-K impact spherules found in the howardites NWA 1664 and NWA 1769 display remarkable trace element patterns. Compared to eucrites or howardites, they all show prominent enrichments in Cs, Rb, K, Li and Ba, strong depletion in Na, while the REE and other refractory elements are unfractionated. These features could not have been generated during impact melting of their host howardites, nor other normal HED target materials. The involvement of Na-poor rocks, and possibly rocks of granitic composition, appears likely.Although these lithologies cannot be well constrained at present, our results demonstrate that the surface of Vesta is certainly more diverse than previously thought. Indeed, despite the large number of available HED meteorites (about 1000 different meteorites), the latter are probably not sufficient to describe the whole surface of their parent body. ACCEPTED MANUSCRIPT3

show abstract

Section: Origin Of the Unusual Trace Element Patterns Of The High-k Smentioning

confidence: 97%

Section: Origin Of the Unusual Trace Element Patterns Of The High-k Smentioning

confidence: 99%

Section: Origin Of the Unusual Trace Element Patterns Of The High-k Smentioning

confidence: 99%

See 1 more Smart Citation

Trace element geochemistry of K-rich impact spherules from howardites

Barrat

Yamaguchi

Greenwood

et al. 2009

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

show abstract

“…Other chondrites (Murchison,Allende,Vigarano '93,Leoville '93,Indarch,Allegan,Krahenberg) were dissolved in Teflon bombs. The two Krahenberg fractions were obtained from the study of Wlotzka et al ( 1983) to investigate the effects of veining. Chips of fusion crust were obtained from a =4 cm stone of Murchison.…”

Section: Chondriresmentioning

confidence: 99%

Potassium isotope cosmochemistry: Genetic implications of volatile element depletion

Humayun

Clayton

1995

Geochimica et Cosmochimica Acta

306

185

View full text Add to dashboard Cite

“…The depletion factor reaches about 100 times for Ni and is greater for Ir. The high Co/Ni ratio in the clast resembles ratios from a K-rich fragment in the Bhola LL-chondrite (Wlotzka et al, 1983) and from chondrules with low siderophile elements from Semarkona (Grossman and Kallemeyn et al (1989), Masuda et al (1973), De Laeter andHosie (1978), Minster and Allegre (1979), Shimizu and Masuda (1986), and Wasson and Kallemeyn (1988). tData from Anders and Grevesse (1990) and Nakamura (1974).…”

Section: Elemental Abundancesmentioning

confidence: 92%

A noritic clast from the Hedjaz chondritic breccia: implications for melting events in the early solar system.

et al. 1992

View full text Add to dashboard Cite

and Au were deter mined in a unique, noritic clast carrying a fractionated REE component from the Hedjaz (L) chondritic breccia by instrumental neutron activation analysis and isotope dilution mass spectrometry. The clast, previously described by Nakamura et al. (1990), consists of two lithologies, and is depleted in siderophile and moderately volatile lithophile elements when compared with its host meteorite. The REE abundance pattern of the clast is L-chondritic (1.4-1.6 x CI-chondrite) with a large (62%), positive Eu anomaly. Strontium is also enriched (3.2 x CI-chondrite) relative to trivalent REE.Chemical and petrologic data suggest that the elemental fractionations observed in the Hedjaz noritic clast could be accomplished in a single host-like parent body with several episodes of impact melting and heating. An impact melt enriched in feldspar components could have been generated in a neighboring region on a parent body, and then infiltrated into the precursor material of the clast. An enhancement of plagiophile elements would then be produced in the clast. Moderately volatile element and siderophile element fractionations could be related to gas /solid or gas /liquid processes and silicate/metal melt fractionations, respectively, which may have occurred during melting and formation of the clast.

show abstract

Alkali differentiation in LL-chondrites

Cited by 39 publications

References 25 publications

Trace element geochemistry of K-rich impact spherules from howardites

Trace element geochemistry of K-rich impact spherules from howardites

Potassium isotope cosmochemistry: Genetic implications of volatile element depletion

A noritic clast from the Hedjaz chondritic breccia: implications for melting events in the early solar system.

Contact Info

Product

Resources

About