Non-marine Carbonate (Joint/Dike) Filling In The Injana Formation, Kand Anticline, NE-Iraq

Riparian clastic beds of fluvial origin in the Injana Formation (Upper Miocene) of Kand anticline exhibit the development of a vertical joint/dike like structure in host sandstone overlying red mudstone. These structures indicate filling from above with sandy carbonate showing texture of floating clastic grains in a micritic calcite stained with red iron oxide pigment. This is capped by siltstone-very fine sandstone enriched with iron oxide and preserved diatom vestiges as chert spheroids; accompanied by oval-irregular vugs lined with microcrystalline calcite. These beds are topped by fossil-barren micritic carbonate of intraclastic texture.
The clastic-carbonate package is interpreted as non-marine fluvial-lacustrine deposits of interchannel depression (pond-lake). Episodic exposure with incipient plant root penetrations, desiccation and differential compaction have led to fissure cracking; otherwise tectonic jointing is entailed. A terminal stage of enlargement by descending water was conducive to the genesis of these joint/dike structures which were filled later by reworked, reshaped and modified sediments sourced from juxtaposed-nearby areas.