Chronology and weathering history of red dunes (Teri Sands) in the southwest coast of Tamil Nadu, India

Coastal landscape evolution in the Wilpattu National Park (NW Sri Lanka) linked to changes in sediment supply and rainfall across the Pleistocene–Holocene transition

“…Comparison of red dune sedimentary records from Sri Lanka (a: this study; d: Singhvi et al, 1986) and Tamil Nadu (b: Jayangondaperumal et al, 2012; c: Alappat et al, 2013, 2016) and their correlation with records of palaeo‐monsoon activity in Sri Lanka (e: Ranasinghe, Ortiz, Smith, et al, 2013; g: Premathilake & Gunatilaka, 2013) and with regional (1: Rein, Lückge, & Sirocko, 2004; Khider, Stott, Emile‐Geay, Thunell, & Hammond, 2011; 2: Kessarkar, Rao, Naqvi, & Karapurkar, 2013; 3: f: Tiwari, Ramesh, Somayajulu, Jull, & Burr, 2005) and global climatic events. The green vertical lines indicate radiometric ages and the dashed curves show the eustatic (A: Lambeck, Rouby, Purcel, Sun, & Sambridge, 2014) and regional (B: Katupotha, 2015) sea‐level records for the last deglaciation and Holocene [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…The red clayey sands in the upper part of the Point Kudrimalai section (Beds 4 and 5; Figures 3 and 6e) represent Red Beds of aeolian origin (Wallace, 2016). Their characteristic red colour is post‐depositional and due to the release of free iron oxides from the in‐situ weathering of ferromagnesian minerals (e.g., garnet, amphibole and pyroxene; Jayangondaperumal et al, 2012; Alappat et al, 2016; Wallace, 2016). The released iron oxides are then precipitating as thin coatings around quartz grains and staining the clay matrix (Alappat et al, 2016).…”

“…Their characteristic red colour is post‐depositional and due to the release of free iron oxides from the in‐situ weathering of ferromagnesian minerals (e.g., garnet, amphibole and pyroxene; Jayangondaperumal et al, 2012; Alappat et al, 2016; Wallace, 2016). The released iron oxides are then precipitating as thin coatings around quartz grains and staining the clay matrix (Alappat et al, 2016). The latter is a product from the in‐situ weathering of feldspars, which are supplied en masse by the island's metamorphic basement together with the ferromagnesian minerals and quartz (Alappat et al, 2016).…”

“…The research of red sands in Sri Lanka therefore concentrates on their mineralogy and economic significance along with a few studies on pedogenesis and archaeological content (Cooray, 1995; Deraniyagala, 1976, 1986; Panabokke, 1996; Wallace, 2016), whereas the depositional architecture and history remains unclear (Katupotha, 1994). On the opposite side of the Gulf of Mannar (SE Tamil Nadu, India) a facies equivalent to the Red Beds is present with the Teri Sands (also referred as ‘Teri Red Sands/Teris’ in the literature; Alappat, Joseph, Tsukamoto, Kaufhold, & Frechen, 2016; Gardner & Martingell, 1990; Singhvi, Deraniyagala, & Sengupta, 1986; Wallace, 2016). The basic concept in interpreting the depositional history of the red fossil dunes is that periods of sand accumulation are related to (semi‐)arid climatic conditions and the reddening occurred when the climatic conditions became more humid with enhanced precipitation (Gardner & Martingell, 1990).…”

“…The basic concept in interpreting the depositional history of the red fossil dunes is that periods of sand accumulation are related to (semi‐)arid climatic conditions and the reddening occurred when the climatic conditions became more humid with enhanced precipitation (Gardner & Martingell, 1990). More recently, it has been shown that dune development in the coastal area of eastern Tamil Nadu was linked not only to dry climatic conditions but also to wind strength and supply or availability of sediment, controlled by vegetation cover and sea‐level changes (Alappat et al, 2016; Alappat, Seralathan, Shukla, Thrivikramji, & Singhvi, 2013; Jayangondaperumal, Murari, Sivasubramanian, Chandrasekar, & Singhvi, 2012; Kunz, Frechen, Ramesh, & Urban, 2010). Red palaeo‐dunes are widely distributed in the coastal area of South China (Old Red Sand) as well and have been used there as palaeo‐climate archive for investigating variations in the East Asian Winter Monsoon intensity during the late Quaternary (Hu et al, 2013).…”