Chapter 1 The Geochemistry of Continental Carbonates

Stable isotope-based reconstruction of Oligo-Miocene paleoenvironment and paleohydrology of Central Anatolian lake basins (Turkey)

“…The δ 18 O carb values from both the Mut and Ecemiş sections are relatively low (22‰ to 25‰). Together with the low δ 13 C carb values (-6‰ to -1‰), the overall restricted oxygen and carbon isotope variability, the published palynological data, and the lack of aridity indicators in the sedimentary facies, the combined Mut/Ecemiş record most likely reflects a hydrologically open lake system with large water volumes and stable lake levels developed under a relatively humid climate with a positive precipitationevaporation balance (Figure 9a; Leng & Marshall 2004;Deocampo 2010). …”

“…Evaporation, itself governed by temperature and relative humidity, strongly controls the depletion in the light oxygen isotope 16 O in the water phase. Changes in temperature, rainfall sources, riverine influx, and groundwater input are retained in the oxygen isotope ratios of carbonates (δ 18 O carb ) which precipitate from lake water (e.g., Turner et al 1983;Talbot 1990;Teranes et al 1999;Lamb et al 2000;Schwalb & Dean 2002;Leng & Marshall 2004;Yansa et al 2007;Davis et al 2009;Deocampo 2010;Kent-Corson et al 2010 (Leng & Marshall 2004). Lacustrine carbonate oxygen isotope records have been also used in isotopebased paleoelevation models exploiting the systematic relationship between oxygen isotopes in precipitation and surface elevation (e.g., Currie et al 2005;Garzione et al 2008;Mix et al 2011;Campani et al 2012).…”

What do we really know about early diagenesis of non-marine carbonates?

“…8) (Allan and Matthews, 1982;Özkul et al, 2013;Della Porta, 2015;Deocampo, 2010;Pentecost, 2005). It varies strongly with spatial and temporal changes in environmental conditions (temperature, rainfall, evaporation, hydrology) and fluid composition (Fig.…”

“…8), carbonate mineralogy (e.g. aragonite versus calcite, Tarutani et al, 1969;Romanek et al, 1992;Patterson et al, 1993;Thorrold et al, 1997;White et al, 1999;Böhm et al, 2000;Lécuyer et al, 2004) and to kinetic effects due to fast degassing and high precipitation rates or in-stream biological activity, organic matter degradation (Andrews and Riding, 2000;Fouke et al, 2000;Andrews, 2006), pH and temperature of precipitation (Deocampo, 2010;Swart, 2015). Carbon and oxygen stable isotope signatures can thus be valuable archives of paleoenvironmental, and -climatic variations with seasonal, annual or decadal resolution (Fairchild et al, 2006;Kawai et al, 2009;Tanner, 2010;Renaut et al, 2013;Frantz et al, 2014), especially when records of different deposits (e.g.…”

Sedimentology, diagenesis and ichnology of Cretaceous and Palaeogene calcretes and palustrine carbonates from Uruguay

“…The formation of groundwater calcretes is also favoured under semi-arid conditions (Alonso-Zarza and Wright, 2010b). ln addition, there is no formation of dolomite which would indicate more saline lakes if present (Deocampo, 2010). In short, the two limestone units studied in this paper formed under semi-arid climates in very shallow freshwater lakes.…”