玉美人传媒

My presentation will introduce briefly my background, my vision and the department I belong to at TU Delft (Geoscience and Engineering). I will then develop the four ongoing projects I have with my research group. These projects focus on fracture network simplification, on management of data uncertainties, identification of the flow signature of natural fracture networks, impact of robust structural models on the prediction of geological heterogeneities. The presentation will describe initially how these topics are classically approached in the academic and industrial communities and will propose alternative workflows to tackle these issues.

The Sun has gotten 25% brighter since it formed. Concurrent with this solar brightening, there is evidence for dramatic changes in the composition of Earth鈥檚 atmospheric greenhouse. The climatic response to these changes must underpin our understanding of Earth鈥檚 physical climate system. However, there has been vigorous debate about the climatic response, as constrained by the oxygen isotopic composition (飦�18O) of marine sedimentary rocks. This ~4-billion-year isotopic record has yielded two contrasting end-member interpretations. In one, 飦�18O of seawater has remained approximately constant, and the temperature of Earth鈥檚 surface has decreased from an early 70-80掳C to the present global average of ~15掳C. In the other, the global average temperature has been approximately constant and 飦�18O of seawater has increased by 10-15 permil. These two end-member scenarios have profoundly different implications for Earth鈥檚 climate through geologic time, the mechanisms that regulate it, and the effects on a wide range of Earth-system properties. To address this gap, we developed the 飦�18O of marine iron oxides, which strongly suggests an increase in seawater 飦�18O over Earth history rather than high early temperatures. Using this new record and existing isotopic data, we show that Earth鈥檚 temperature has largely been regulated at a global average of ~10-20掳C, with implications for long-timescale climate-stabilizing feedbacks. In a spectacular exception to this rule of climate regulation, some of our samples come from a ~50-million-year-long global glaciation, the Sturtian 鈥渟nowball Earth鈥�. We use these samples to reveal that during this interval a staggering 15-30% of Earth鈥檚 water was locked in ice. Despite the frozen surface conditions, our results also require substantial evaporative fluxes from regions of open water and suggest that at least half of the ice came from snowfall in an active hydrological cycle.

The magma ocean that existed on the early Earth finally solidified to form a coherent lithosphere. This lithosphere insulated the underlying mantle leading to warming, thermal expansion, partial melting and a geoid bulge. This in turn may trigger breakup of the lithosphere and the onset of plate tectonics. As a consequence, heat balance is disturbed, which results in thermal fluctuation. On a global scale, a cycle of warming and cooling happened many times throughout geological history. This in turn may induce geological events as a response to the thermal cycles. The speaker will present a simple model of Earth evolution as a thermal system, based on rock fracture modeling method, trying to answer many questions about Earth鈥檚 history that are as yet unanswered.