Bedrock response to Llanquihue Holocene and present‐day glaciation in southernmost South America

Modern geodetic techniques, such as precise Global Positioning System (GPS) measurements and high resolution space gravity mapping, make it possible to measure the present‐day rate of viscoelastic gravitational Earth response to present and past glacier mass change. Patagonia is a rapidly evolving glacial environment. Over the past decade, the local rate of surface stress unloading may be the largest anywhere on the planet. We compute the present‐day land uplift rate that could be observed using bedrock GPS measurements. The Little Ice Age (LIA) of the past half millennium generates large vertical rates since the underlying mantle material is likely to have anomalously low viscosity owing to late‐Neogene ridge subduction.

[1]  Erik R. Ivins,et al.  Simple models for late Holocene and present-day Patagonian glacier fluctuations and predictions of a geodetically detectable isostatic response , 1999 .

[2]  E. Ivins,et al.  Ice mass balance and antarctic gravity change: satellite and terrestrial perspectives , 2005 .

[3]  D. Wolf.  The normal modes of a layered, incompressible Maxwell half-space , 1985 .

[4]  M. Salemme,et al.  When Patagonia was colonized: people mobility at high latitudes during Pleistocene/Holocene transition , 2003 .

[5]  R. Purves,et al.  The Last Glacial Maximum and deglaciation in southern South America , 2002 .

[6]  R. Purves,et al.  Climatic inferences from glacial and palaeoecological evidence at the last glacial termination, southern South America , 2000 .

[7]  J. Wahr,et al.  GPS measurements of vertical crustal motion in Greenland , 2001 .

[8]  M. Salemme,et al.  Quaternary of Tierra del Fuego, Southernmost South America: an updated review , 2000 .

[9]  R. Kilian,et al.  Role of the subducted slab, mantle wedge and continental crust in the generation of adakites from the Andean Austral Volcanic Zone , 1996 .

[10]  J. Rabassa,et al.  Cold climatic episode of Younger Dryas age in Tierra del Fuego , 1987, Nature.

[11]  J. Johansson,et al.  Continuous GPS measurements of postglacial adjustment in Fennoscandia 1. Geodetic results , 2002 .

[12]  R. Purves,et al.  Modelling the inception of the Patagonian icesheet , 2002 .

[13]  Jeffrey T. Freymueller,et al.  Rapid uplift of southern Alaska caused by recent ice loss , 2004 .

[14]  B. Singer,et al.  40Ar/39Ar and K-Ar chronology of Pleistocene glaciations in Patagonia , 2004 .

[15]  Masamu Aniya,et al.  Late Pleistocene and Holocene palaeoclimate and glacier fluctuations in Patagonia , 2004 .

[16]  Jan M. Johansson,et al.  Continuous GPS measurements of postglacial adjustment in Fennoscandia: 2. Modeling results: FENNOSCANDIAN GPS MODELING RESULTS , 2004 .

[17]  G. Wenzens.  Comment: climatic inferences from glacial and palaeoecological evidence at the last glacial termination, southern South America. R.D. McCulloch, M.J. Bentley, R.S. Purves, N.R.J. Hulton, D.E. Sugden and C.M. Clapperton (2000) (Journal of Quaternary Science, 15, 409–417) , 2001 .

[18]  Fred F. Pollitz,et al.  Mobility of continental mantle: Evidence from postseismic geodetic observations following the 1992 Landers earthquake , 2000 .

[19]  M. Aniya.  Recent Glacier Variations of the Hielos Patagónicos, South America, and Their Contribution to Sea-Level Change@@@Recent Glacier Variations of the Hielos Patagonicos, South America, and Their Contribution to Sea-Level Change , 1999 .

[20]  R. Villalba,et al.  Large-Scale Temperature Changes across the Southern Andes: 20th-Century Variations in the Context of the Past 400 Years , 2003 .

[21]  John J. Clague,et al.  Postglacial rebound at the northern Cascadia subduction zone , 2000 .

[22]  S. Kay,et al.  Mantle Processes and Sources of Neogene Slab Window Magmas from Southern Patagonia, Argentina , 2001 .

[23]  Joseph S. Resovsky,et al.  Probabilistic Tomography Maps Chemical Heterogeneities Throughout the Lower Mantle , 2004, Science.

[24]  Masamu Aniya,et al.  Recent Glacier Variations of the Hielos Patagonicos, South America, and Their Contribution to Sea-level Change , 1999 .

[25]  C. Clapperton,et al.  Quaternary glaciations of the southern Andes , 1990 .

[26]  E. Ivins,et al.  Predictions of Antarctic crustal motions driven by present-day ice sheet evolution and by isostatic memory of the Last Glacial Maximum , 1998 .

[27]  Eric Rignot,et al.  Contribution of the Patagonia Icefields of South America to Sea Level Rise , 2003, Science.

[28]  C. Heusser.  On glaciation of the southern Andes with special reference to the Penı́nsula de Taitao and adjacent Andean cordillera (∼46°30′s) , 2002 .