Dr. Frits Hilgen

Universitair hoofddocent
Stratigraphy & paleontology
f.j.hilgen@uu.nl

SUMMARY OF MY RESEARCH CARRIED OUT SINCE I STARTED AS PHD (a long time ago)

 

PhD thesis: An astronomical time scale for the Mediterranean Plio-Pleistocene 

During my PhD I established an astronomical  time scale for the Mediterranean Pliocene, in close collaboration with Jan-Willem Zachariasse, and Hans Zijderveld and Cor Langereis of the Paleomagnetic Laboratory Fort Hoofddijk. One of the main section used in my thesis is the Rossello Composite section located in the coastal cliffs of southern Sicily. Much later I suggested that this section should be defined as tuned unit stratotype of the Zanclean and Piacenzian Stages and Milankovitch cycles as chronozones. The tuning basically still underlies the age calibration of the standard geological time scale of this time interval. Below is the picture of the Punta di Maiata partial section that is depicted on the cover of the second volume of GTS2012.

Punta di Maiata, Sicily, Italy

 

Post-doctoral research: Elaboration and extension of the astronomical time scale into the Miocene

As postdoctoral "Academy" fellow, I continued to work in Utrecht with Jan-Willem and Cor, and Lucas Lourens and Wout Krijgsman as PhDs on the elaboration and extension of this time scale. For this purpose, we used among others the Gibliscemi section on Sicily which clearly reveals the eccentricity related bundling of precession related sapropels.

Monte Gibliscemi section, Sicily, Italy

 

The continental record of the Mediterranean

I also started to work on continental successions in the Mediterranean, initially in Greece, as part of the COMCOM-project, with Joris Steenbrink, Nicole van Vugt and Marloes Kloosterboer as PhDs, and later in Spain with Hayfaa Adul Aziz and Hemmo Abels as PhDs. Astronomical climate forcing was detectable all sections and marine-continental correlations could be established down to the precession scale.

Precession related in the Pliocene continental succession of Ptolemais, Greece.

Precession related cycles in the lacustrine succession of Orera (Miocene, Spain).

 

The continental record of North America

During the last decade, my research interest in the astronomical climate control on continental sedimentary environments switched from the Mediterranean to North America where, again with Hayfaa Abdul Aziz and Hemmo Abels, I focused in close collaboration with Phil Gingerich and Mary Kraus on the fluvial successions of the Eocene Willwood Formation in the Bighorn Basin. This study expanded to include the Fort Union Fm in Montana and the Hoseshoe Canyon Fm in Alberta, Canada, partly within the framework of GTSnext. We now continue to work in Montana within the framework of the VIDI project of Klaudia Kuiper with Lars Noorbergen as PhD.

Eocene reddish paleosols in the PETM of the Polecat Bench section suggesting a precessional control

Coal alternations in the Tullock Mb of the Fort Union, Bug Creek, Montana with the K/Pg boundary at the base of the first coaly layer.

 

Messinian Salinity Crisis

After establishing an astronomical time scale for the Messinian in an attempt to better understand the salinity crisis many years ago, I returned to the MSC within the framework of the EU-ITN Medgate. This network aims to further improve our comprehension of the MSC mainly through multi- and interdisciplinary research.

Vena del Gesso gypsum in northern Italy, showing precession controlled cyclicity. 

 

Intercalibration with radio-isotopic dating

The intercalibration of the astronomical dating method with radio-isotopic dating plays a crucial role in the extension of the ATS into the Cretaceous. I started to collaborate with Jan Wijbrans of the Ar/Ar lab at the VU many years ago with aim to compare astronomical and Ar/Ar dating. This led to the very successful PhD thesis of Klaudia Kuiper and in collaboration with Paul Renne and Al Deino of the Berkeley Geochrology Center we established an astronomical age for the Fish Canyon sanidine, the most widely standard in Ar/Ar geochronology and used this age to constrain the astronomical tuning of the K/Pg boundary. This age was selected by the Ar/Ar community and adopted in the standard Geological Time Scale (GTS2012). Currently, this issue is highly contoversial with other FCs ages published. With the EU-ITN GTSnext, of which I was coordinator, we brought leading european experts in Ar/Ar, U/Pb and astronomical dating together in an attempt to intercalibrate these methods and solve the existing problems in the ATS.

Part of the Messadit section in Morocco with precession related cycles used for the tuning and one of the prominent white ashbeds used for Ar/Ar dating. 

 

Top part of the Danian Limestones, used for tuning and showing hierarchy of precession and eceentricity related cycles

 

Climate modeling of orbital extremes

The last important subject I worked on is the use of climate models to better understand astronomical climate forcing. We started this research direction in close collaboration with the late Prof. Nanne Weber of the KNMI and continued our collaboration with Sybren Drijfhout. Two PhD students, Erik Tuenter and Joyce Bosmans, were involved in this research and they concentrated mainly on the climate modeling of orbital extremes. Focus was especially on low-latitude monsoonal systems and also on the Atlantic system.

 

SUMMARY

Summarizing, the construction and application of the astronomical time scales proved of great importance among others for understanding 1) the history of the Messinian Salinity crisis, 2) astronomical-induced climate changes as recorded in marine and continental archives, and 3) the intercalibration with radio-isotopic dating.