ARTÍCULO
TITULO

The Morphological Characteristics of Authigenic Pyrite Formed in Marine Sediments

Jingyi Chang    
Yuanyuan Li and Hailong Lu    

Resumen

Pyrites are widely distributed in marine sediments, the morphology of which is applied as a proxy to infer the redox conditions of bottom water, and identify diagenetic stages and hydrocarbon leakage activities. In this review, the methods used for the morphological study of pyrite are summarized. The textural and size characteristics of euhedral pyrite and pyrite aggregates, as the formation and evolution mechanism of pyrite are discussed for their significance in reconstructing the geochemical environment. The morphological study of pyrite includes shape observation, size estimation, and surface feature analysis. Scanning electron microscope and optical microscope are the main methods for morphological observation; transmission electron microscope and scanning tunneling microscope are applicable to observe nanoscale morphological structures and crystal growth on the crystal surface, and X-ray computed tomography is capable of measuring pyrite size distribution at the scale of a micrometer. Under the marine sedimentary condition, the single crystal of pyrite appears in cube, octahedron, dodecahedron, and their intermediates, the size of which ranges from several nanometers to more than 100 µm. The morphology of euhedral pyrite is controlled by temperature, pH, the chemical composition of interstitial water, etc., and might have been experienced in later reformation processes. The pyrite aggregates occur as framboid, rod-like, fossil-infilling, etc., characterized by the comparatively large size of several microns to several millimeters. It is found that certain textures correspond with different formation mechanisms and geochemical environments. Particularly, under special geological conditions, for instance, the methane leakage and/or decomposition of gas hydrate, pyrite is anomaly enriched with morphological textures of massive framboid cluster, rod-like aggregates, etc., and framboid is found with a large mean diameter (>20 µm) and standard deviation (>10 µm). These typical features can be employed to ascertain the position of the paleo sulfate methane transition zone (SMTZ).

 Artículos similares

       
 
Bohyeon Hwang, Kideok Do and Sungyeol Chang    
Constant changes occur in coastal areas over different timescales, requiring observation and modeling. Specifically, modeling morphological changes resulting from short-term events, such as storms, is of great importance in coastal management. Parameter ... ver más

 
Ryan Good, David Nguyen, Hossein Bonakdari, Andrew Binns and Bahram Gharabaghi    
Predicting morphological adjustments in alluvial meandering streams remains a challenging task due to the complex nature of the governing inter-related dynamic flow and sediment transport processes. This difficulty is increased in streams with irregular ... ver más
Revista: Water

 
Basharat Ali, Anwarzeb Khan, Syed Shujait Ali, Haji Khan, Mehboob Alam, Asmat Ali, Abdulwahed Fahad Alrefaei, Mikhlid H. Almutairi and Ki In Kim    
Water contamination with heavy metals seriously affects water and sediment quality and may affect the aquatic biota. This study assessed the impact of heavy metals on the morphological characteristics of aquatic microorganisms in potentially contaminated... ver más
Revista: Water

 
Pattira Kasamesiri, Ruamruedee Panchan and Wipavee Thaimuangphol    
Microplastic pollution has been identified as a potential threat to the aquatic environment and humans globally, with widespread occurrence in ecosystems, including reservoirs that constitute a key role in ecosystem services for humans. However, the eval... ver más
Revista: Water

 
Hao Liu, Jifei Ye, Mingyu Li and Heyan Gao    
For laser ablation micropropulsion technology with metal as the target to increase the total impulse, the effective utilization and supply of a working medium is a crucial aspect. In this research, the ablation characteristics and propulsion performance ... ver más
Revista: Aerospace