Geology, mineralogy, and geochemistry of the Zarloukh Bentonite −Tuff deposit, Hemrin South Mountain, northern Iraq: implications for genesis and geotectonics

The Quaternary Zarloukh Bentonite -Tuff (ZBT) deposit occurs within the Hemrin South Mountain, northern Iraq. ZBT as depression-filling exposed on erosional surface of siliciclastic Pliocene Muqdadiya Formation and covered by an overburden recent sediments. thickness studied industrial bentonite bed is ~80-100 cm, occurring at bottom these depressions, ~3-4 m thick bedded volcanic tuff, which also contains many 10-12 cm layers along its bedding planes. ash lakes/swamps with shallow water content acted basins for deposition falling ash, immersed in devitrified to a later stage hydration chemical interactions, meanwhile continued fallen consolidated tuff beds protecting formed depressions. shows mini-scale trough crossbedding sign formation low energy, agitated lakes/swamps. precursor show some differences concentration Ca, Mg, Na, K representing exchangeable elements smectite (montmorillonite), predominant clay mineral because probable gain during process bentonitization tuff. has most probably same origin Basalt located NW deposit. chondrite-normalized REEs distribution pattern similar, both showing enrichment negative slope LREEs relative flat-lying HREEs. Th vs. Co Th/ Yb Ta/Yb diagrams indicated that fall field high-K calc-alkaline basalt shoshonite andesitic basalt-andesite rocks reflecting their common origin.