The International Commission on Stratigraphy (ICS) has a long tradition of producing international charts that communicate higher-order divisions of geological time and actual knowledge on the absolute numerical ages of their boundaries. The primary objective of ICS is to define precisely a global standard set of time-correlative units (Systems, Series, and Stages) for stratigraphic successions worldwide. These units are, in turn, the basis for the Periods, Epochs and Ages of the Geological Time Scale. Setting an international global standard is fundamental for expressing geological knowledge. It is also of considerable pragmatic importance as it provides the framework through which regional-scale higher-resolution divisions can be linked, equated and collated. This is a status update on the International Chronostratigraphic Chart and the ICS website www.stratigraphy.org.

The ICS International Chronostratigraphic Chart

Insects are the most speciose group of animals, but the phylogenetic relationships of many major lineages remain unresolved. We inferred the phylogeny of insects from 1478 protein-coding genes. Phylogenomic analyses of nucleotide and amino acid sequences, with site-specific nucleotide or domain-specific amino acid substitution models, produced statistically robust and congruent results resolving previously controversial phylogenetic relations hips. We dated the origin of insects to the Early Ordovician [~479 million years ago (Ma)], of insect flight to the Early Devonian (~406 Ma), of major extant lineages to the Mississippian (~345 Ma), and the major diversification of holometabolous insects to the Early Cretaceous. Our phylogenomic study provides a comprehensive reliable scaffold for future comparative analyses of evolutionary innovations among insects.

https://science.sciencemag.org/content/sci/346/6210/763.full.pdf

Phylogenomics resolves the timing and pattern of insect evolution

This report summarizes the international divisions and ages in the Geologic Time Scale, published
in 2012 (GTS2012). Since 2004, when GTS2004 was detailed, major developments have taken place
that directly bear and have considerable impact on the intricate science of geologic time scaling. Precam brian
now has a detailed proposal for chronostratigraphic subdivision instead of an outdated and abstract chronometric
one. Of 100 chronostratigraphic units in the Phanerozoic 63 now have formal definitions, but stable
chronostratigraphy in part of upper Paleozoic, Triassic and Middle Jurassic/Lower Cretaceous is still wanting.
Detailed age calibration now exist between radiometric methods and orbital tuning, making 40Ar-39Ar dates
0.64% older and more accurate. In general, numeric uncertainty in the time scale, although complex and not
entirely amenable to objective analysis, is improved and reduced. Bases of Paleozoic, Mesozoic and Cenozoic
are bracketed by analytically precise ages, respectively 541 0.63, 252.16 0.5, and 65.95 0.05 Ma.
High-resolution, direct age-dates now exist for base-Carboniferous, base-Permian, base-Jurassic, base-Cenomanian
and base-Eocene. Relative to GTS2004, 26 of 100 time scale boundaries have changed age, of which
14 have changed more than 4 Ma, and 4 (in Middle to Late Triassic) between 6 and 12 Ma. There is much
higher stratigraphic resolution in Late Carboniferous, Jurassic, Cretaceous and Paleogene, and improved integration
with stable isotopes stratigraphy. Cenozoic and Cretaceous have a refined magneto-biochronology.
The spectacular outcrop sections for the Rosello Composite in Sicily, Italy and at Zumaia, Basque Province,
Spain encompass the Global Boundary Stratotype Sections and Points for two Pliocene and two Paleocene
stages. Since the cycle record indicates, to the best of our knowledge that the stages sediment fill is stratigraphically
complete, these sections also may fulfill the important role of stage unit stratotypes for three of
these stages, Piacenzian, Zanclean and Danian

On The Geologic Time Scale

Time is divided by geologists according to marked shifts in Earth's state. Recent global environmental changes suggest that Earth may have entered a new human-dominated geological epoch, the Anthropocene. Here we review the historical genesis of the idea and assess anthropogenic signatures in the geological record against the formal requirements for the recognition of a new epoch. The evidence suggests that of the various proposed dates two do appear to conform to the criteria to mark the beginning of the Anthropocene: 1610 and 1964. The formal establishment of an Anthropocene Epoch would mark a fundamental change in the relationship between humans and the Earth system.

https://bertaux.files.wordpress.com/2015/04/3-12-15-lewis-maslin-defining-the-anthropocene-nature14258.pdf

Defining the Anthropocene

This paper reviews the basic principles of radiometric geochronology as implemented in a new software package called IsoplotR, which was designed to be free, flexible and future-proof. IsoplotR is free because it is written in non-proprietary languages (R, Javascript and HTML) and is released under the GPL license. The program is flexible because its graphical user interface (GUI) is separated from the command line functionality, and because its code is completely open for inspection and modification. To increase future-proofness, the software is built on free and platform-independent foundations that adhere to international standards, have existed for several decades, and continue to grow in popularity. IsoplotR currently includes functions for U-Pb, Pb-Pb, 40 Ar/ 39 Ar, Rb-Sr, Sm-Nd, Lu-Hf, Re-Os, U-Th-He, fission track and U-series disequilibrium dating. It implements isochron regression in two and three dimensions, visualises multi-aliquot datasets as cumulative age distributions, kernel density estimates and radial plots, and calculates weighted mean ages using a modified Chauvenet outlier detection criterion that accounts for the analytical uncertainties in heteroscedastic datasets. Overdispersion of geochronological data with respect to these analytical uncertainties can be attributed to either a proportional underestimation of the analytical uncertainties, or to an additive geological scatter term. IsoplotR keeps track of error correlations of the isotopic ratio measurements within aliquots of the same samples. It uses a statistical framework that will allow it to handle error correlations between aliquots in the future. Other ongoing developments include the implementation of alternative user interfaces and the integration of IsoplotR with other data reduction software.

IsoplotR: A free and open toolbox for geochronology

The Geologic Time Scale 2012, winner of a 2012 Prose Award Honorable Mention for Best Multi-volume Reference in Science from the Association of American Publishers, is the framework for deciphering the history of our planet Earth. The authors have been at the forefront of chronostratigraphic research and initiatives to create an international geologic time scale for many years, and the charts in this book present the most up-to-date, international standard, as ratified by the International Commission on Stratigraphy and the International Union of Geological Sciences. This 2012 geologic time scale is an enhanced, improved and expanded version of the GTS2004, including chapters on planetary scales, the Cryogenian-Ediacaran periods/systems, a prehistory scale of human development, a survey of sequence stratigraphy, and an extensive compilation of stable-isotope chemostratigraphy. This book is an essential reference for all geoscientists, including researchers, students, and petroleum and mining professionals. The presentation is non-technical and illustrated with numerous colour charts, maps and photographs. The book also includes a detachable wall chart of the complete time scale for use as a handy reference in the office, laboratory or field. This is the most detailed international geologic time scale available that contextualizes information in one single reference for quick desktop access. It gives insights in the construction, strengths, and limitations of the geological time scale that greatly enhances its function and its utility. It aids understanding by combining with the mathematical and statistical methods to scaled composites of global succession of events. It meets the needs of a range of users at various points in the workflow (researchers extracting linear time from rock records, students recognizing the geologic stage by their content).

The Geologic Time Scale 2012

Introduction Planetary time scale Precambrian period Cambrian period Ordovician period Silurian period Devonian period Carboniferous period Permian period Triassic period Jurassic period Cretaceous period Paleogene period Neogene period Quaternary period Appendix Standard colors of the international divisions of geologic time References Index

The Concise Geologic Time Scale

This guide provides a major revision and update of the lithostratigraphy of the Rogaland Group for the Norwegian North Sea. An abundance of recent well and seismic data sheds new light on lithology, biostratigraphy, provenance, geographic distribution and terminology of all Rogaland rock units, used widely in the search for oil and gas. While finer siliciclastic units largely remain as previously defined, previous sandstone/siltstone formations and one (reworked) chalky unit are now re-defined. These lithostratigraphic units are local sediment bodies of a lithology different from the surrounding and embracing formation. Hence, these lithostratigraphic units are members in the formal stratigraphical hierarchy. With the new definitions and re-definitions the Rogaland Group now consists of four formations and 15 members, which span the stratigraphic interval from lower Paleocene to lower Eocene. The revisions concerning the sandstone bodies are of four different types: – Re-definition from formations to members – Re-definition of lithological criteria – Introduction of members long used already offshore England and Denmark – Definition of new members For those practicing geologists not familiar with historic precedence, an important ʻsine qua nonʼ in (litho-) stratigraphy, it should be pointed out that 8 out of 15 members discussed here have been predefined in literature dealing with the UK and Danish sectors of the North Sea. The present study thus updates the Norwegian lithostratigraphic bulletins of the nineteen eighties for its offshore area. The internet site www.nhm2.uio.no/ norlex provides an interactive digital version of this study, with links to well data, biozonations and core archives relevant to the Rogaland Group.

Stratigraphic guide to the Rogaland Group, Norwegian North Sea

Chapter 4 on the Cryogenian and Ediacaran of a Concise Geologic TimeScale 2016 is an overview of the status of its global divisions and boundary placements (GSSPs) of the major "Snowball Earth" glaciations, the main biological events leading to the earliest animal life (the Ediacaran fauna), aspects of stable-isotope trends and magnetic polarity patterns, major sediment cycles and sea-level changes, and an age model for scaling these events and trends. The majority of the brief chapter consists of summary graphics.

Cryogenian and Ediacaran

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1755-6724.14245

Gabi M. Ogg

Papers

The Geologic Time Scale 2012

The Concise Geologic Time Scale

Stratigraphic guide to the Rogaland Group, Norwegian North Sea

Cryogenian and Ediacaran

Global Paleogeography through the Proterozoic and Phanerozoic: Goals and Challenges