Why did the Germanic rock sequence have drawbacks as a standard for dating Triassic rocks worldwide?

The primary drawback of the Germanic rock sequence as a standard for dating Triassic rocks worldwide is its origin. While the sequence, proposed in the 19th century by Friedrich August von Alberti, provided a clear division into three units—the Bunter, Muschelkalk, and Keuper—it is composed mostly of continental, rather than marine, deposits.12

Because the Germanic facies lacks the continuous marine fossil record necessary for global correlation, it could not serve as an effective standard for assigning relative ages to Triassic strata found in other regions. Consequently, geologists traditionally relied on the Alpine facies in Austria, Switzerland, and Italy, which contains marine sequences. Since the mid-20th century, even more complete sequences discovered in North America have become the preferred standard for Triassic time.12