372 PRINCIPLES OF STRATIGRAPHY 



11. Kieserite zone averaging i8 m. 



12. Polyhalite zone averaging 35 m. 



13. Older Rock Salt with about 3,000 "annual" rings 



of anhydrite averaging 245 m. 



Nos. II, 12, and 13 have a combined thickness 

 ranging from 150 to perhaps 1,000 meters.* 

 The "annual" rings of anhydrite form layers 

 averaging 7 millimeters thick, separating the 

 salt into sheets of 8 or 9 millimeters. 



14. Older anhydrite and gypsum (Anhydrite I) 



averaging lOO m. 



15. Zechstein limestone or dolomite 



16. Kupferschiefer 



17. Zechstein conglomerate 



18. Upper Rothliegende (base of section) 



The lower members, beginning with Anhydrite I and ending with 

 the carnallite zone (and sometimes the kainite, sylvinite and schoen- 

 ite zones), form one depositional series, the last being the salts from 

 the mother liquor. This is followed by a protecting layer of clay. 

 Apparently a second depositional series began with the second or 

 main anhydrite and the Younger Rock Salt, but lacks the mother 

 liquor salts. 



Altogether more than thirty saline minerals are found in the 

 Stassfurt deposit. Of these some of the more prominent besides the 

 halite and anhydrite are : 



Carnallite KMgCls.eHaO 



Kieserite MgS04.H20 



Polyhalite 2CaSO4.MgSO4.K2SO4.2H2O 



Kainite MgSO^.KCl.pHjO 



Sylvite KCl (Sylvinite is a mixture of sylvite and rock salt; 



Hartsalz contains these substances together with 



Kieserite). 

 Schoenite MgSO,.K2S04.6H20 



Borates, especially boracite (Mg^CLB^gOgo), occur with the carnal- 

 lite and in the overlying zone. A noteworthy fact is that these de- 

 posits are absolutely unfossiliferous, in spite of the fact that organic 

 remains would here have a chance for perfect preservation. 



These deposits have been commonly regarded as illustrations of 

 the Bar Theory, but against this interpretation strong objections 

 have been urged, especially by Walther (62:63) and by Erdmann 

 (16). Walther uses as his main arguments against such an origin 

 the absolute want of organic remains in these deposits, and the fur- 



* This is probably the result of thickening through subsequent diagenetic 

 processes, the average of the salt deposits in undisturbed regions being about 

 350 meters. 



