Glendonite occurrences in the Tremadocian of Baltica: first Early Palaeozoic evidence of massive ikaite precipitation at temperate latitudes

The Tremadocian (Early Ordovician) is currently considered a time span of greenhouse conditions with tropical water surface temperature estimates, interpolated from oxygen isotopes, approaching 40°C. In the high-latitude Baltoscandian Basin, these data are in contrast with the discovery of glendonite, a pseudomorph of ikaite (CaCO3·6H2O) and valuable indicator of near-freezing bottom-water conditions. The massive precipitation of this climatically sensitive mineral is associated with transgressive conditions and high organic productivity. Surprisingly, the precipitation of glendonite is contemporaneous with the record of conodonts displaying low δ18O values, which would suggest high temperatures (>40°C) in the water column. Therefore, the early Tremadocian sediments of Baltoscandia contain both “greenhouse” pelagic signals and near-freezing substrate indicators. This apparent paradox suggests both the influence of isotopically depleted freshwater yielded by fluvial systems, and the onset of sharp thermal stratification patterns in a semi-closed basin, which should have played an important role in moderating subpolar climates and reducing latitudinal gradients.

[1]  M. Rogov,et al.  Earliest Cretaceous (late Berriasian) glendonites from Northeast Siberia revise the timing of initiation of transient Early Cretaceous cooling in the high latitudes , 2017 .

[2]  L. Timokhov,et al.  Shelf basin exchange along the Siberian continental margin: Modification of Atlantic Water and Lower Halocline Water , 2016 .

[3]  A. Prokoph,et al.  Temperatures and oxygen isotopic composition of Phanerozoic oceans , 2015 .

[4]  M. Joachimski,et al.  Lower-Middle Ordovician δ13C chemostratigraphy of western Baltica (Jämtland, Sweden) , 2015 .

[5]  A. Soesoo,et al.  Centimetre-scale variability of redox-sensitive elements in Tremadocian black shales from the eastern Baltic Palaeobasin , 2014 .

[6]  B. Teichert,et al.  Glendonites from an Early Jurassic methane seep — Climate or methane indicators? , 2013 .

[7]  J. Trotter,et al.  Calibration of the phosphate δ18O thermometer with carbonate–water oxygen isotope fractionation equations , 2013 .

[8]  J. Hölemann,et al.  The Arctic shelf regions as a source of freshwater and brine-enriched waters as revealed from stable oxygen isotopes , 2011 .

[9]  A. Bonin,et al.  Revised phosphate–water fractionation equation reassessing paleotemperatures derived from biogenic apatite , 2010 .

[10]  G. Price,et al.  Valanginian isotope variation in glendonites and belemnites from Arctic Svalbard: Transient glacial temperatures during the Cretaceous greenhouse , 2010 .

[11]  A. Gale,et al.  Surface-water freshening and high-latitude river discharge in the Eocene North Sea , 2009, Journal of the Geological Society.

[12]  R. Spielhagen,et al.  Evidence from Svalbard for near-freezing temperatures and climate oscillations in the Arctic during the Paleocene and Eocene , 2009 .

[13]  C. Barnes,et al.  Did Cooling Oceans Trigger Ordovician Biodiversification? Evidence from Conodont Thermometry , 2008, Science.

[14]  B. Jones,et al.  A Review and Synthesis of Glendonites (Pseudomorphs after Ikaite) with New Data: Assessing Applicability as Recorders of Ancient Coldwater Conditions , 2007 .

[15]  R. Ethington,et al.  OXYGEN ISOTOPIC COMPOSITION OF BIOGENIC PHOSPHATE AND THE TEMPERATURE OF EARLY ORDOVICIAN SEAWATER , 2007 .

[16]  N. Schovsbo,et al.  Cambrian to basal Ordovician lithostratigraphy in southern Scandinavia , 2006 .

[17]  J. Welker,et al.  Spatial distribution and seasonal variation in 18O/16O of modern precipitation and river water across the conterminous USA , 2005 .

[18]  T. Torsvik,et al.  Baltica from the late Precambrian to mid-Palaeozoic times: The gain and loss of a terrane's identity , 2005 .

[19]  R. Dalrymple,et al.  Glendonites in Neoproterozoic low-latitude, interglacial, sedimentary rocks, northwest Canada: Insights into the Cryogenian ocean and Precambrian cold-water carbonates , 2005 .

[20]  A. T. Nielsen.  10. Ordovician Sea Level Changes: A Baltoscandian Perspective , 2004 .

[21]  Gabriel J. Bowen,et al.  Spatial distribution of δ18O in meteoric precipitation , 2002 .

[22]  I. Swainson,et al.  Ikaite, CaCO3·6H2O: Cold comfort for glendonites as paleothermometers , 2001 .

[23]  L. Frakes,et al.  Glendonites as a paleoenvironmental tool: implications for early Cretaceous high latitude climates in Australia , 1999 .

[24]  H. Schulz,et al.  Correlation between Arabian Sea and Greenland climate oscillations of the past 110,000 years , 1998 .

[25]  Hartmut Schulz,et al.  Correlation between Arabian Sea and Greenland climate oscillations of the past 110,000 years , 1998, Nature.

[26]  W. Bednarczyk,et al.  TREMADOC OF THE EAST EUROPEAN PLATFORM - LITHOFACIES AND PALAEOGEOGRAPHY , 1997, Proceedings of the Estonian Academy of Sciences. Geology.

[27]  D. Larsen.  Origin and paleoenvironmental significance of calcite pseudomorphs after ikaite in the Oligocene Creede Formation, Colorado , 1994 .

[28]  D. Guy-Ohlson,et al.  Palynomorph content of the uraniferous alum shales of Cambrian-Ordovician age in Sweden , 1990 .

[29]  L. Popov,et al.  THE CAMBRIAN-ORDOVICIAN BOUNDARY IN THE BALTIC-LADOGA CLINT AREA (NORTH ESTONIA AND LENINGRAD REGION, USSR) , 1986, Proceedings of the Academy of Sciences of the Estonian SSR. Geology.

[30]  M. Lindström.  Do ‘white sand crosses’ from the Lower Cambrian of Kinnekulle have glendonite affinity? , 1984 .