Diagenetic formation of gypsum and dolomite in a cold‐water coral mound in the Porcupine Seabight,off Ireland     

HANS PIRLET  LAURA M. WEHRMANN  BENJAMIN BRUNNER  NORBERT FRANK  JAN DEWANCKELE  DAVID VAN ROOIJ  ANNELEEN FOUBERT  RUDY SWENNEN  LIEVEN NAUDTS  MATTHIEU BOONE  VEERLE CNUDDE  JEAN‐PIERRE HENRIET 《Sedimentology》2010,57(3):786-805

Authigenic gypsum was found in a gravity core, retrieved from the top of Mound Perseverance, a giant cold‐water coral mound in the Porcupine Basin, off Ireland. The occurrence of gypsum in such an environment is intriguing, because gypsum, a classic evaporitic mineral, is undersaturated with respect to sea water. Sedimentological, petrographic and isotopic evidence point to diagenetic formation of the gypsum, tied to oxidation of sedimentary sulphide minerals (i.e. pyrite). This oxidation is attributed to a phase of increased bottom currents which caused erosion and enhanced inflow of oxidizing fluids into the mound sediments. The oxidation of pyrite produced acidity, causing carbonate dissolution and subsequently leading to pore‐water oversaturation with respect to gypsum and dolomite. Calculations based on the isotopic compositions of gypsum and pyrite reveal that between 21·6% and 28·6% of the sulphate incorporated into the gypsum derived from pyrite oxidation. The dissolution of carbonate increased the porosity in the affected sediment layer but promoted lithification of the sediments at the sediment‐water interface. Thus, authigenic gypsum can serve as a signature for diagenetic oxidation events in carbonate‐rich sediments. These observations demonstrate that fluid flow, steered by environmental factors, has an important effect on the diagenesis of coral mounds.  相似文献   

Using Multiphase Solid Inclusions to Constrain the Origin of the Baima Fe-Ti-(V) Oxide Deposit, SW China     

LIU Pingping  ZHOU Meifu  CHEN Weiterry  BOONE Marijn  CNUDDE Veerle 《《地质学报》英文版》2015,89(Z2):56-56

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PHASE UNWRAPPING,POSSIBILITIES AND LIMITATIONS*     

E. POGGIAGLIOLMI  A. J. BERKHOUT  M. M. BOONE 《Geophysical Prospecting》1982,30(3):281-291

An unwrapped phase curve from the principal values of the phase can be computed in a simple way. The validity of the unwrapping procedure is tested by exploiting the phase information in the signal's first moment. The significance of the unwrapped answer around notches in the amplitude spectrum is seriously degraded by noise. The proposed method and the validity test are illustrated with examples.  相似文献