In Tuoyun area of southwestern Tianshan, mantle and lower crust xenoliths are present In the volcanic rocks with ages of 101-123 Ma. Mantle xenoliths include mineral megacrysts such as kaersutite and pargasite, feldsp...In Tuoyun area of southwestern Tianshan, mantle and lower crust xenoliths are present In the volcanic rocks with ages of 101-123 Ma. Mantle xenoliths include mineral megacrysts such as kaersutite and pargasite, feldspar, biotite, and rare pyroxene and rock fragments such as perodotite, pyroxenite, amphibolite, and rare glimmerite. Lower crust xenoliths are mainly banded and massive granulite. The volcanic rocks were produced by within-plate magmatism. Occurrence of hydrous and volatile mineral megacrysts, amphibolite, and some pyroxenite containing hydrous and volatile minerals indicates that mantle metasomatism was intense. Undoubtedly, this discovery is very important to understanding of the crust-mantle structure and geodynamic background in depth in southwestern Tianshan and geological correlation with adjacent regions.展开更多
MUD crack is a common bedding-plane structure, but the zigzag mud cracks (figs. 1 and 2) are rare phenomena that were found beside G314 highway from Kaxgar to Taxkorgan in Xin-jiang, China. From the photographs we can...MUD crack is a common bedding-plane structure, but the zigzag mud cracks (figs. 1 and 2) are rare phenomena that were found beside G314 highway from Kaxgar to Taxkorgan in Xin-jiang, China. From the photographs we can find that there are footprints of a small animal at every top of zigzag. The zigzag cracks were controlled admittedly by the animal slightly disturbing just when they were breaking. There is a phenomenon worth researching further (fig. 1 ). Distributing equality of zigzags, the horizontal crack (F1) is cracked along the footprints strictly. The vertical one (F2) was not cracked regularly and confined by F1. The crack was展开更多
文摘In Tuoyun area of southwestern Tianshan, mantle and lower crust xenoliths are present In the volcanic rocks with ages of 101-123 Ma. Mantle xenoliths include mineral megacrysts such as kaersutite and pargasite, feldspar, biotite, and rare pyroxene and rock fragments such as perodotite, pyroxenite, amphibolite, and rare glimmerite. Lower crust xenoliths are mainly banded and massive granulite. The volcanic rocks were produced by within-plate magmatism. Occurrence of hydrous and volatile mineral megacrysts, amphibolite, and some pyroxenite containing hydrous and volatile minerals indicates that mantle metasomatism was intense. Undoubtedly, this discovery is very important to understanding of the crust-mantle structure and geodynamic background in depth in southwestern Tianshan and geological correlation with adjacent regions.
文摘MUD crack is a common bedding-plane structure, but the zigzag mud cracks (figs. 1 and 2) are rare phenomena that were found beside G314 highway from Kaxgar to Taxkorgan in Xin-jiang, China. From the photographs we can find that there are footprints of a small animal at every top of zigzag. The zigzag cracks were controlled admittedly by the animal slightly disturbing just when they were breaking. There is a phenomenon worth researching further (fig. 1 ). Distributing equality of zigzags, the horizontal crack (F1) is cracked along the footprints strictly. The vertical one (F2) was not cracked regularly and confined by F1. The crack was
