Autor Thema: Yucca als neues 'Dense Collection Area' (DCA) benannt  (Gelesen 1427 mal)

Offline karmaka

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Yucca als neues 'Dense Collection Area' (DCA) benannt
« am: März 09, 2013, 15:14:45 Nachmittag »
Yucca als neues 'Dense Collection Area' (DCA) benannt

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Zitat
New Yucca Dense Collection Area (8 Mar 2013)

A new dense collection area (DCA) named Yucca is being used to name meteorites in the Franconia area of Mohave County in western Arizona. While many of the recovered meteorites may belong to one fall – colloquially called the Franconia strewnfield, recent research shows the presence of multiple overlapping falls (Hutson et al., 2013). The Yucca DCA incorporates and replaces two smaller DCAs (Buck Mountains, Sacramento Wash). This change is being made to allow meteorites that are being found within and outside of the two previous DCAs to be given the same DCA root name. Fourteen previously named meteorites from this area will retain their names but be given Yucca xxx synonyms, where xxx is a number that reflects the sequence in which meteorites were named. New meteorites will continue this sequence as they are assigned. The names, synonyms, and Meteoritical Bulletin (MB) references are as follows.


Stones from Mohave County, Arizona: Multiple falls in the “Franconia strewn field”

ABSTRACT

Zitat
One of the most productive and well-sampled dense collection areas for meteorites on Earth is the “Franconia strewn field” in Mohave County, Arizona, which since 2002 has yielded hundreds of meteorites in an ellipsoidal area approximately 5 × 16 km across. Based on petrographic, mineral-chemical, and terrestrial age data, we conclude that among 14 meteorites examined, there are at least 6 and possibly 8 distinct meteorites represented, which fell over a period of approximately 0–20 kyr ago. These include equilibrated H-chondrites such as Franconia (H5) and Buck Mountains (BM) 001 (H6); H3–6 breccias such as Buck Mountains Wash and BM 004; and L6 chondrites such as BM 002 and BM 003 (which may be paired), Palo Verde Mine, and BM 005. To confidently pair such meteorites often requires thorough petrographic examination, mineral-chemical analyses, and terrestrial ages. We estimate that 50 ± 10% of the larger specimens in this area are paired, yielding a relatively high value of approximately 2.3–2.9 distinct meteorites km−2. The meteorite flux estimated for Franconia area is higher than the flux inferred from contemporary fireball data for larger masses. We suggest that one large H3–6 meteoroid fell in the area, most likely that of Buck Mountains Wash approximately 4 kyr ago, which produced an elliptical strewn field with masses generally increasing toward one end, and which raised the meteorite productivity in the recovery area.

Data for specimen masses and locations in the Franconia area (EXCEL)

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« Letzte Änderung: März 09, 2013, 15:40:10 Nachmittag von karmaka »

 

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