Mr Julian Martin

Supervised by

Research interests

My research interests focus on reconstructing the timing and extent of past glacier advance and recession and improving our understanding of what drove such events. Specifically, through a combination of geomorphological mapping, cosmogenic nuclide surface exposure dating, and glacier modelling, it is possible to determine the controls of glacier mass balance and improve our understanding of how major atmospheric systems have changed in the past.  

 

Research

Late Quaternary ice dynamics of the Monte San Lorenzo ice cap, Patagonia

Glaciers of small ice caps have short response times and high climate sensitivity, making them a useful proxy for understanding palaeoclimate. Past changes in climate and glacier dynamics can provide an analogue for present-day and future rapid climate and glacier change. Land-terminating glaciers are of particular interest, since their extent is largely a function of temperature and precipitation. Constraining the past behaviour of these glaciers from the geological record and glacier mass-balance sensitivities from numerical modelling can yield insights into past climate change. This is of particular interest in Patagonia to help elucidate the behaviour of the precipitation bearing Southern Westerly Winds, which are changed dynamically during the Late Pleistocene and Holocene. Key climatic constraints on glaciers east of the Northern Patagonian Icefield are also poorly understood, complicated by a lack of understanding of interactions between glaciers and ice-dammed palaeolakes. This study presents a new reconstruction of the deglaciation of the northern Monte San Lorenzo ice cap, southern South America, during a period of accelerated warming following the Antarctic Cold Reversal. Detailed geomorphological mapping of the valleys north of Monte San Lorenzo reveals 14 primary ice limits, two of which were dated to 12.5 ± 0.4 ka and 12.1 ± 0.4 ka by cosmogenic nuclide dating. Glacial landsystem analysis enables and formalises the reconstruction of Antarctic Cold Reversal and Holocene glacier dynamics and glacier-lake interactions. This work underpins a numerical model (PISM) of the ice cap to evaluate palaeoclimate drivers. Climatic and physical parameter sensitivity experiments and climatic response time tests provide, for the first time, an important insight into the controls of glacier change and the response of temperate Patagonian glaciers to rapidly-warming climate. Forcing the model using temperature and precipitation combinations to match reconstructed ice limits provides estimates of past climate conditions following the Antarctic Cold Reversal.

Educational background

2015-2019 PhD (Quaternary Science), Department of Geography, Royal Holloway University of London

2010-2014 MSci Geology, Department of Earth Science and Engineering, Imperial College London

Teaching

Remote sensing and GIS - 1st, 2nd and 3rd year undergraduate

Southern Spain field course - 1st year undergraduate

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