Long Beach,
25
June
2018
|
01:35 AM
America/Los_Angeles

Collapse of Civilizations Worldwide Defines Youngest Unit of the Geologic Time Scale

Summary

LONG BEACH, Calif. (June 25, 2018) – The Late Holocene Meghalayan Age, newly-ratified as the most recent unit of the Geologic Time Scale, began at the time when agricultural societies around the world experienced an abrupt and critical mega-drought and cooling 4,200 years ago.

FOR IMMEDIATE RELEASE

Contact: Stan.Finney@csulb.edu / 562-985-8637

LONG BEACH, Calif. (June 25, 2018) – The Late Holocene Meghalayan Age, newly-ratified as the most recent unit of the Geologic Time Scale, began at the time when agricultural societies around the world experienced an abrupt and critical mega-drought and cooling 4,200 years ago.

Agriculture-based societies developed in several regions after the end of the last Ice Age, before a 200-year climatic event affected agricultural societies, forcing the collapse of civilizations and migrations and regenerations in Egypt, Greece, Syria, Palestine, Mesopotamia, the Indus Valley, and the Yangtze River Valley. Evidence of this period, now called the 4.2 kiloyear climatic event, has been found on all seven continents.

The Meghalayan Age is unique among the many intervals of the Geologic Time Scale in that its beginning coincides with a cultural event produced by a global climatic event, according to Dr. Stanley Finney, professor of geological sciences at Long Beach State University and Secretary General of the International Union of Geological Sciences (IUGS).

The convergence of stratigraphy and human cultural evolution is extraordinary, according to Martin Head, a geologist at Brock University in Canada and Chair of the International Subcommission on Quarternary Stratigraphy.

Yale University’s Harvey Weiss, professor of environmental studies and Near Eastern languages, considers this decision to be a significant moment in the history of Holocene climate and archaeology science.

The International Commission on Stratigraphy, which is responsible for standardizing the Geologic Time Scale, approved the definition of the beginning of the youngest unit of the Geologic Time Scale based on the timing of this event. Furthermore, it approved proposals for two other ages: the Middle Holocene Northgrippian Age and the Early Holocene Greenlandian Age with beginnings defined at climatic events that happened about 8,300 years and 11,700 years ago, respectively. The three ages comprise the Holocene Epoch, which represents the time since the end of the last Ice Age. The Commission then forwarded these proposals to its parent body, the IUGS, for consideration, and the executive committee of IUGS voted unanimously to ratify them.

Units of the Geologic Time Scale are based on sedimentary strata that have accumulated over time and contain within them sediment types, fossils and chemical isotopes that record the passage of time as well as the physical and biological events that produced them.

The three new ages of the Holocene Epoch are represented by a wealth of sediment that accumulated worldwide on the sea floor, on lake bottoms, as glacial ice, and as calcite layers in stalactites and stalagmites. Those sedimentary strata on which the ages are based are referred to as stages, and together these strata comprise the Holocene Series.

The lower boundary of the Greenlandian and Northgripppian stages are defined at specific levels in Greenland ice cores. The lower boundary of the Meghalayan Stage is defined at a specific level in a stalagmite from a cave in northeast India. The ice cores and the stalagmite are now identified as international geostandards, and have been placed in protected archives accessible for further study.

The decision to define these new stages of the Holocene Series and thus the three new corresponding ages of the Holocene Epoch allows for an update to the International Chronostratigraphic Chart (www.stratigraphy.org), which depicts the timeline for the earth’s full geologic history.

This is a key achievement for the International Union of Geological Sciences and particularly for its Commission on Stratigraphy. The proposals were developed by a dedicated, international team of Holocene scientists led by Mike Walker of University of Wales. They were subsequently approved by the International Subcommission of Quaternary Stratigraphy and the International Commission on Stratigraphy before being forward to IUGS for ratification. According to Professor David Harper of Durham University in the United Kingdom and Chair of the International Commission on Stratigraphy, the many years of scientific research and international collaboration followed by intense scrutiny of the proposals as they are evaluated at several levels in the IUGS organization give legitimacy to the new units as global standards

As Secretary General of IUGS, Finney administered the vote involving members of its Executive Committee and released the results today.

About the campus: Long Beach State University is a teaching-intensive, research-driven university committed to providing highly valued undergraduate and graduate degrees critical for success in the globally minded 21st century. Annually ranked among the best universities in the West and among the best values in the entire nation, the university’s eight colleges serve more than 37,500 students. The campus values and is recognized for rich educational opportunities provided by excellent faculty and staff, exceptional degree programs, diversity of its student body, fiduciary and administrative responsibility and the positive contributions faculty, staff, students and more than 300,000 alumni make on society.

About the International Commission on Stratigraphy:The International Commission on Stratigraphy is the largest and oldest constituent scientific body in the International Union of Geological Sciences (IUGS). Its primary objective is to precisely define global units (systems, series, and stages) of the International Chronostratigraphic Chart that, in turn, are the basis for the units (periods, epochs, and age) of the International Geologic Time Scale; thus setting global standards for the fundamental scale for expressing the history of the Earth.

Photo: (Credit – Stanley C. Finney, CSULB) A portion of Indian stalagmite that was sectioned and analyzed layer by layer, and contains the layers chosen to define the beginning of the Late Holocene Meghalayan Age, 4,200 years ago.