Carbonate cements pedogenic

Accumulation of calcium carbonate due to pedogenic processes Nearly continuously cemented horizons (by various pedogenic minerals) Accumulation of exchangeable sodium... 

The dominant types of cementation in the Zia Formation are pedogenic and phreatic. By definition, the spatial distribution of pedogenic carbonate is a function of the spatial distribution of palaeo-sols, which is a function of facies architecture and the length of time a particular surface was exposed. Most pedogenic carbonate in the Zia Formation is poorly developed, discontinuous and associated with finer-grained sediments in overbank fines (OF), crevasse splay (CS), and interdune (ID) facies associations (see Table 1 Fig. 6). Unlike discontin-... 

Cementation in the phreatic zone occurred preferentially in zones of high primary permeability, whereas vadose cementation occurred principally in association with soil development. Pedogenic carbonates may have served as nucleation sites for later phreatic cementation, leading to complex zones of mixed pedogenic and phreatic cements. 

The absence of dolomite cement at sandbody bases and its abundance at sandbody tops, the reported organic carbon isotope signal in the rhombic ferroan dolomite and the mixture of pedogenic dolomite textures and burial diagenetic textures in the sandbodies suggests that options 1 and 4 together are probably responsible for, the distribution of dolomite in the Chaunoy sandbodies. 

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