"wt%" refers to weight per hundred, Thus, assuming the given percentage (w%) are indeed " weight per weight percent" (wt/wt), 4.09 % (wt/wt) means 4.09 gram iron per 100 g of earth crust.

 Thank u very much prof. Juergen Wiegel. 

Saif ultimate lelan.o.09% = 0.09 Gm  Fe  in  100 Gm  crust

Thank u very much Dr. Noori Kh Fayad

see attachment

 Dear Dr. Ketil Haarstad,

A lot of thanks.

kind regards

Thank u very much dear Mr. Toskë L. Kryeziu