Cryptic (geology)
The Cryptic era is an informal term for the earliest geologic evolution of the Earth and Moon. It is the oldest (informal) era of the Hadean eon, and it is commonly accepted to have begun close to 4533 million (about 4.533 billion) years ago when the Earth and Moon formed. No samples exist to date the transition between the Cryptic era and the following Basin Groups era for the Moon (see also Pre-Nectarian), though sometimes it is stated that this era ended 4150 million years ago for one or both of these bodies. Neither this time period, nor any other Hadean subdivision, has been officially recognized by the International Commission on Stratigraphy.
Universal history
The Bronze Age forms part of the three-age system. In this system, it follows the Neolithic Age in some areas of the world. In the 24th century BC, the Akkadian Empire was founded. The First Intermediate Period of Egypt (c. 22nd century BC) was followed by the Middle Kingdom of Egypt between the 21st to 17th centuries BC. The Sumerian Renaissance also developed c. 21st century BC. Around the 18th century BC, the Second Intermediate Period of Egypt began. By 1600 BC, Mycenaean Greece developed, the beginning of the Shang Dynasty in China emerged and there was evidence of a fully developed Chinese writing system. Also around 1600 BC, the beginning of Hittite dominance of the Eastern Mediterranean region is seen. From the 16th to 11th centuries BC the New Kingdom of Egypt dominated the Nile Valley. Between 1550 BC and 1292 BC, the Amarna Period developed.