The Formation and Structure Evolution of Zechstein (Upper Permian) Salt in Northeast German Basin: A Review

Abstract

The Zechstein (Upper Permian) salts are extensively distributed in the Northeast German Basin (NEGB). Their formation and movements have attracted great attention to discover ing the accumulation and exploration of hydrocarbon sources, as well as the salt production. But the previous studies are validated in cases and a general view on these studies is scarce. By analyzing and integrating previous studies, the history and structure evolution of Zechstein salts were reviewed in this paper. Seven cycles of Zechstein salt (Na1, Na2, Na3, Na4, Na5, Na6, Na7) with distinct composition and thickness were deposited after a series of marine transgressions and regressions during the Upper Permian. The Na1 ( 300 m ) locally developed in a lagoon environment. The thick Na2 (over 500 m ) was widely deposited in the whole basin. The Na3, Na4, Na5, Na6 and Na7 decreased progressively in thickness and distribution. These salts should have been moved as a result of regional tectonics taking place from Triassic to Early Cenozoic, which change s the original distribution of salts, resulting in the formation of different salt structures (pillows and diapirs). Salt movement was more intensive in central and southern parts of the basin forming narrow and widely-distributed salt diapirs, while it was less intensive in the northern parts where salt pillows are the major structure. The salt meadow and saline springs are also present, which are attributed to the salinization of the groundwater. By this study, we review the history and structure development of the Zechstein salt in the NEGB by associating each individual study and figure out the common and regional characters of the salt in this region.