The carbonaceous chondrites are intriguing and unique in the sense that they are the only rocks that provide pristine records of the early solar nebular processes. We report here results of a detailed mineralogical, c...The carbonaceous chondrites are intriguing and unique in the sense that they are the only rocks that provide pristine records of the early solar nebular processes. We report here results of a detailed mineralogical, chemical, amino acid and isotopic studies of a recently observed fall at Mukundpura, near Jaipur in Rajasthan, India. Abundance of olivines in this meteorite is low and of serpentine minerals is high. FeO/SiO_2 = 1.05 in its Poorly Characterized Phases(PCP) is similar to that observed in other CM2.0 chondrites. The water content of ～9.8 wt.% is similar to that found in many other CM chondrites.Microscopic examination of matrix shows that its terrestrial weathering grade is WO but aqueous parent body alteration is high, as reflected in low abundance of identifiable chondrules and abundant remnants of chondrules(～7%). Thus, most of the chondrules formed initially have been significantly altered or dissolved by aqueous alterations on their parent bodies. The measured bulk carbon(2.3%) and nitrogen content and their isotopic(δ^(13)C =-5.5‰, δ^(15)N = 23.6%0) composition is consistent with CM2.0 classification probably bordering CM1. Several amino acids such as Alanine, Serine, Proline, Valine, Threonine,Leucine, Isoleucine, Asparagine and Histamine are present. Tyrosine and Tryptophan may occur in trace amounts which could not be precisely determined. All these data show that Mukundpura chondrite lies at the boundary of CM2.0 and CM1 type carbonaceous chondrites making it one of the most primitive chondrites.展开更多
We report here for the first time the composition and mineralogical studies on a new meteorite, which fell in Dhayala ki Chappar （24°58°N, 73° 48°27°E） 5 km NW of Nathdwara in south Rajastha...We report here for the first time the composition and mineralogical studies on a new meteorite, which fell in Dhayala ki Chappar （24°58°N, 73° 48°27°E） 5 km NW of Nathdwara in south Rajasthan, India, on Dec. 25th, 2012. Mineralogical and compositional studies were carried out on a representative piece of the Nathdwara meteorite sample. The mineralogical composition of the meteorite has been found to be olivine （42 45 vol.%）, feldspar （10-15 vol.%）, orthopyroxene （23-25 vol.%）, troilite （6 8 vol.%）, and titanium bearing minerals （6-8 vol.%）. Our investigations show that the Nathdwara meteorite belongs to H6 group of ordinary chondrites.展开更多
基金carried out with the support of MOES-PMN and PLANEX (Physical Research Laboratory, Ahmedabad) programs
文摘The carbonaceous chondrites are intriguing and unique in the sense that they are the only rocks that provide pristine records of the early solar nebular processes. We report here results of a detailed mineralogical, chemical, amino acid and isotopic studies of a recently observed fall at Mukundpura, near Jaipur in Rajasthan, India. Abundance of olivines in this meteorite is low and of serpentine minerals is high. FeO/SiO_2 = 1.05 in its Poorly Characterized Phases(PCP) is similar to that observed in other CM2.0 chondrites. The water content of ～9.8 wt.% is similar to that found in many other CM chondrites.Microscopic examination of matrix shows that its terrestrial weathering grade is WO but aqueous parent body alteration is high, as reflected in low abundance of identifiable chondrules and abundant remnants of chondrules(～7%). Thus, most of the chondrules formed initially have been significantly altered or dissolved by aqueous alterations on their parent bodies. The measured bulk carbon(2.3%) and nitrogen content and their isotopic(δ^(13)C =-5.5‰, δ^(15)N = 23.6%0) composition is consistent with CM2.0 classification probably bordering CM1. Several amino acids such as Alanine, Serine, Proline, Valine, Threonine,Leucine, Isoleucine, Asparagine and Histamine are present. Tyrosine and Tryptophan may occur in trace amounts which could not be precisely determined. All these data show that Mukundpura chondrite lies at the boundary of CM2.0 and CM1 type carbonaceous chondrites making it one of the most primitive chondrites.
文摘We report here for the first time the composition and mineralogical studies on a new meteorite, which fell in Dhayala ki Chappar （24°58°N, 73° 48°27°E） 5 km NW of Nathdwara in south Rajasthan, India, on Dec. 25th, 2012. Mineralogical and compositional studies were carried out on a representative piece of the Nathdwara meteorite sample. The mineralogical composition of the meteorite has been found to be olivine （42 45 vol.%）, feldspar （10-15 vol.%）, orthopyroxene （23-25 vol.%）, troilite （6 8 vol.%）, and titanium bearing minerals （6-8 vol.%）. Our investigations show that the Nathdwara meteorite belongs to H6 group of ordinary chondrites.
