# How does the synthesis of Kaolinite (and it's by products) influence porosity in granodiorite?

I started studying the effects of weathering on granodiorite (see previous posts) and plan on referencing the link between the chemical weathering of feldspar plagioclase leading to kaolinization, a process I am relatively unfamiliar with. In brief terms, how would this reaction reduce the porosity of the rock? Also, how would the release of $Ca$ and $K$ influence further degradation of the rocks porosity?

• Wouldn't it increase porosity? link.springer.com/article/10.1007%2Fs12665-011-1015-y Unless I wonder if the granodiorites you are studing are weathered and kaolinite and other neoformed minerals may plug the holes if they are at surface and weathered. – Universal_learner Jun 6 '18 at 9:31
• They are slightly weathered. So it seems the production of kaolinite increases porosity? – Yaboy33 Jun 6 '18 at 9:37
• The weathering and chemical proccess is asociated. They should be porous because of the proccess, but clays plug the holes, so porosity is still big, but effective porosity has decreased because of clays. – Universal_learner Jun 6 '18 at 9:39
• @Universal_learner What about the transition of granodiorite to a saprolite form. These are apparently more-porous and clay-based (kaolinite). Am I missing something? – Yaboy33 Jun 6 '18 at 9:44
• The transition -at my climate on spain- I read is K-feldspar->kaolinite. I understand you are at the transition between mass rock and saprolite. Clays are very waterproof, water reservoirs are placed on clays frequently. The weathering proccess is what has started porosity. Saprolite will be very porous. it will become a regolite. Of course the gradient is porosity increase if you look at the hole proccess of soil formation. – Universal_learner Jun 6 '18 at 10:02