People at Fort Hoofddijk

Roderic Bosboom
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R.E. Bosboom, MSc
Paleomagnetic Laboratory
Fort Hoofddijk
Department of Earth Sciences
Utrecht University 
Budapestlaan 17, 3584 CD Utrecht 
The Netherlands 

Phone +31 30 253 5246


Research of Roderic Bosboom

Paleogene Sea Retreat of the Early Paratethys from Central Asia and Asian Paleoenvironmental Change
The Paleogene sediments of the Central Asian basins include the remnants of the easternmost extent of a large epicontinental sea. This shallow marine sea once extended across the Eurasian continent before it retreated westward and became known as the Paratethys Sea. 
Despite the common notion that the formation of the Tibetan Plateau primarily governed paleoenvironmental changes in Asia, climate modeling experiments suggest this sea served as a major moisture contributor governing Asian monsoons and aridification of the Asian continental interior. 

Paleogeographic map showing the extent of marine conditions after the last major sea retreat from the Tarim Basin, time equivalent with a major aridification phase in the Xining Basin at 36.6 Ma

The age and paleogeography of the sea retreat in Central Asia remain poorly constrained, however, hampering our understanding of its paleoenvironmental impacts and its controlling mechanisms, which are generally interpreted to be related either to eustatic sea-level fall or to sedimentary overfilling resulting from initial uplift of the surrounding mountain ranges in the Indo-Asia collision system. 

Accordingly, our research is twofold. 

(1) In the southwest Tarim Basin in west-China and in the Alay Valley and Ferghana Basin in Kyrgyzstan we focus on the transgression-regression cycles recorded by the shallow marine sediments of Paleogene age. 

(2) In the Xining Basin along the northeastern margin of the Tibetan Plateau we study sedimentary successions which have recorded the major step-wise aridification in the so-called doubthouse period preceding the Eocene-Oligocene transition from global greenhouse to icehouse conditions. 

Interval of the Shuiwan section in the Xining Basin with small scale cycle numbers. 
Black-white bar represents 5 m in stratigraphy. White arrow is the location of the first lithofacies and paleoenvironmental change at 36.6 Ma correlative to the sea retreat in the Tarim Basin.
By using multiple litho-, magneto- and biostratigraphic constraints from these key sedimentary successions, an extensive regional stratigraphic framework will be constructed in both areas, which helps to improve understanding of the link between the sea retreat and contemporaneous paleoenvironmental changes in Asia.

Field view of the Aertashi section in the southwest Tarim Basin (west China)
So far, our research on the Paleogene marine-continental records in the southwest Tarim Basin confirms that the last major sea retreat from the paleo-depocentre coincides with a significant aridification step in the Xining Basin in the early Priabonian (36.6 Ma). Furthermore, the sea retreat clearly pre-dates major events which were usually held responsible for the sea retreat: 
  1. Oligocene-Miocene regional uplift of the Pamir mountains, Tian Shan and Kunlun Shan, and 
  2. Major eustatic sea-level falls of the Eocene-Oligocene Transition (~34 Ma) and mid-Oligocene (~30 Ma). 

The Tarim Basin team in our base camp

Clearly, higher resolution age control is required to better constrain the paleoenviron- mental impacts (i.e. aridification, regional biotic reorganizations) and controlling mechanisms (i.e. tectonically-induced early stage basin infilling vs. eustatic sea-level fall) of this significant retreat and to provide valuable insight into the regional tectonic and paleogeographic evolution of Central Asia.

The project is supervised by Guillaume Dupont-Nivet, as part of his NWO VIDI project.

publications Publications of Roderic Bosboom
  • Bosboom, R. E., Dupont-Nivet, G., Mandic, O., Proust, J. N., Ormukov, C., Amminov, J. (2015). Late Eocene paleogeography of the Proto-Paratethys Sea in Central Asia (NW China, S Kyrgyzstan, and SW Tajikistan), In: Brunet, M.-F.,McCann, T. & Sobel, E. R. (eds), Geological Evolution of Central Asian Basins and the Western Tien Shan Range. Geological Society, London, Special Publications, 427, 
  • Yang,W., Dupont-Nivet, G., Jolivet, M., Guo, Z., Bougeois, L., Bosboom, R., Zhang, Z., Zhu, B. and Heilbronn, G. (2015), Magnetostratigraphic record of the early evolution of the southwestern Tian Shan foreland basin (Ulugqat area) , interactions with Pamir indentation and India-Asia collision, Tectonophysics, 644-645, 122-137. 

  • Bosboom, R.E. (2013). Paleogeography of the Central Asian proto-Paratethys Sea in the Eocene: Controlling mechanisms and paleoenvironmental impacts (PhD Thesis), Utrecht Studies in Earth Sciences, Volume 38.   
  • Abels, H.A., Dupont-Nivet, G., Xiao, G., Bosboom, R.E. and Krijgsman, W. (2011). Step-wise change of Asian interior climate preceding the Eocene–Oligocene Transition (EOT). Palaeogeography, Palaeoclimatology, Palaeoecology, 299, 399-412. 
  • Bosboom, R.E., Dupont-Nivet, G., Houben, A.J.P., Brinkhuis, H., Villa, G., Mandic, O., Stoica, M., Zachariasse, W.J., Guo, Z., Li, C. and Krijgsman, W. (2011). Late Eocene sea retreat from the Tarim Basin (west China) and concomitant Asian paleoenvironmental change, Palaeogeography, Palaeoclimatology, Palaeoecology, 299, 385-398.