by David Middleton, June 6 , 2019 in WUWT
What is a highstand?
A highstand is one phase of the sea level cycle (AAPG Wiki)
The highstand is the maximum sea level achieved during the cycle.
The Holocene Epoch
The Holocene Epoch was recently formally subdivided into three stages:
- Greenlandian Stage = Lower or Early-Holocene. 11.70 ka to 8.33 ka
- Northgrippian Stage = Middle or Mid-Holocene. 8.33 ka to 4.25 ka
- Meghalayan Stage = Upper or Late-Holocene. 4.25 ka to present
The abbreviation “ka” refers to thousands of years ago. Lower, Middle and Upper are generally used when referring to rock-time units. Early, Mid and Late are generally used when referring to time units (Haile, 1987). Prior to the formal subdivision, Lower/Early, Middle/Mid and Upper/Late were commonly used; however there was no formal nomenclature. The fake word, “Anthropocene” is not used by real geologists.
There is also an informal climatological subdivision of the Holocene:
- Preboreal 10 ka–9
- Boreal 9 ka–8 ka
- Atlantic 8 ka–5 ka
- Subboreal 5 ka–2.5 ka
- Subatlantic 2.5 ka–present
Why would there have been a Mid- to Late-Holocene highstand?
Figure 1. Holocene sea level curves from Moore & Curray, 1974.