The Effect of Depositional Setting on Alteration of Landing Ash

ZHANG Hui; ZHOU An chao; GUO Min tai; JIA Bing wen

By the aid of X ray diffractometer, transmit electron microscopes (TEM) and scQan electron microscopes (SEM), authors have revealed the altered features of landing ash from Daqingshan Inner Mongolia Late Paleozoic era (C 2—P 1 ), and discussed the effect of depositional setting on ash alteration. In peat moor, the landing ash is directly altered into kaolinite in situ,forming cryptocrystalline kaolinite mudstone. The mudstone is almost monomineralic and keeps the shapes of crystallinoclastic and shard. Under TEM, the kaolinites in the form of unitary and aggregate are mostly glassy.Their arris are not tidy, with different shapes small particle size and strong aggregation. Under SEM, worm kaolinites and pisolite kaolinites are usually paragenetic. Both made up porphyritic texture in the range of micron. In non peat moor, the landing ash is firstly altered into gel, then into clay minerals in allochthon, becoming clay mudstone. The mudstone is polymineralic, with mineral components composed of illite, montmorillonite and interstratified illite montmorillonite and so on. Under TEM, the kaolinites are coagulative and clastic; under SEM, the sedimentary characters are often seen, such as microbedding and microbedding plane made up of oriented clay minerals. After the ash transferred by air deposits, its alteration and products in peat moor are different from non peat moor because the conditions of physics and chemistry vary with environment. The paper shows much to insight on deeply understanding of volcanic event strata and studing genesis of kaolinton in coal series.

1. Xi'an Branch of China Coal Research Institute,Xi'an 710054;

2. Taiyuan University of Technology,Taiyuan 030024

Received Date: 1999-08-18

Rev Recd Date: 1999-11-16

Publish Date: 2000-08-10

Key words:

Abstract: By the aid of X ray diffractometer, transmit electron microscopes (TEM) and scQan electron microscopes (SEM), authors have revealed the altered features of landing ash from Daqingshan Inner Mongolia Late Paleozoic era (C 2—P 1 ), and discussed the effect of depositional setting on ash alteration. In peat moor, the landing ash is directly altered into kaolinite in situ,forming cryptocrystalline kaolinite mudstone. The mudstone is almost monomineralic and keeps the shapes of crystallinoclastic and shard. Under TEM, the kaolinites in the form of unitary and aggregate are mostly glassy.Their arris are not tidy, with different shapes small particle size and strong aggregation. Under SEM, worm kaolinites and pisolite kaolinites are usually paragenetic. Both made up porphyritic texture in the range of micron. In non peat moor, the landing ash is firstly altered into gel, then into clay minerals in allochthon, becoming clay mudstone. The mudstone is polymineralic, with mineral components composed of illite, montmorillonite and interstratified illite montmorillonite and so on. Under TEM, the kaolinites are coagulative and clastic; under SEM, the sedimentary characters are often seen, such as microbedding and microbedding plane made up of oriented clay minerals. After the ash transferred by air deposits, its alteration and products in peat moor are different from non peat moor because the conditions of physics and chemistry vary with environment. The paper shows much to insight on deeply understanding of volcanic event strata and studing genesis of kaolinton in coal series.

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Reference (11)

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The Effect of Depositional Setting on Alteration of Landing Ash

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