Validated linear mixture modelling of Landsat TM data for mapping evaporite minerals on a playa surface: methods and applications

Abstract The Chott el Djerid is a large salt playa situated in southern Tunisia. The playa has a brine- type of Na-K-Mg-Cl-SO4 and a stable mineral assemblage of gypsum (CaSO4.2H2O), halite (NaCl) and carnallite (KMgCl3.6H2O). From laboratory spectra of the three stable evaporite minerals it was found that gypsum and halite were the only evaporite minerals likely to be differentiated using Landsat TM imagery. Unmixing analysis was then undertaken on a 30 km by 60 km sub-scene of single-date Landsat TM data (April 1986) cover the northern half of the Chott el Djerid. Using principal components analysis (PCA) five end-member cover-types were identified from this image: (1) gypsum, (2) halite, (3) live vegetation, (4) alluvial material and (5) shade/moisture. By applying a linear mixture model to the single-date image, proportions maps for each cover-type were generated for the playa. Errors for each class were found to be (1)0·039, (2)0·059, (3)0·028, (4) 0·052, and (5) 0·061. The proportions maps for gypsu...

[1]  Paul E. Johnson,et al.  Quantitative determination of mineral types and abundances from reflectance spectra using principal components analysis , 1985 .

[2]  T. Lowenstein,et al.  Chapter 3 Depositional Environments of Non-Marine Evaporites , 1991 .

[3]  Robert G. Bryant,et al.  Marine-like potash evaporite formation on a continental playa: case study from Chott el Djerid, southern Tunisia , 1994 .

[4]  Peter Stucki,et al.  Advances in Digital Image Processing , 1979, Springer US.

[5]  H. Eugster.  Geochemistry of Evaporitic Lacustrine Deposits , 1980 .

[6]  James K. Crowley,et al.  Mapping playa evaporite minerals with AVIRIS data: a first report from Death Valley, California , 1993 .

[7]  R. Coque,et al.  La Tunisie présaharienne : étude géomorphologique , 1964 .

[8]  James K. Crowley,et al.  Visible and near‐infrared (0.4–2.5 μm) reflectance spectra of Playa evaporite minerals , 1991 .

[9]  Paul E. Johnson,et al.  Spectral mixture modeling: A new analysis of rock and soil types at the Viking Lander 1 Site , 1986 .

[10]  L. Ratschbacher,et al.  The Xigaze forearc basin: evolution and facies architecture (Cretaceous, Tibet) , 1994 .

[11]  J. Townshend,et al.  Monitoring sediment transport systems in a semiarid area using thematic mapper data , 1989 .

[12]  M. Rosen.  Sedimentologic and geochemical constraints on the evolution of Bristol Dry Lake Basin, California, U.S.A , 1991 .

[13]  Y. Tardy,et al.  Geochemistry of brines of the chott El Jerid in southern Tunesia — Application of Pitzer's equations , 1983 .

[14]  A. Jones,et al.  Remote sensing of sediment transfer processes in playa basins , 1987, Geological Society Special Publication.

[15]  D. Rothery,et al.  Remote sensing of evaporite mineral zonation in salt flats (salars) , 1989 .

[16]  J. Townshend,et al.  Monitoring salt playa dynamics using Thematic Mapper data , 1989 .

[17]  J. Settle,et al.  Linear mixing and the estimation of ground cover proportions , 1993 .

[18]  T. Lowenstein,et al.  Criteria for the recognition of salt-pan evaporites , 1985 .

[19]  J. Townshend,et al.  Monitoring playa sediment transport systems using thematic mapper data , 1989 .

[20]  Robert G. Bryant,et al.  The Chemical Evolution of the Brines of Chott EL Djerid, Southern Tunisia, After an Exceptional Rainfall Event in January 1990 , 1994 .

[21]  H. Eugster,et al.  Behavior of major solutes during closed-basin brine evolution , 1979 .