Late Cretaceous–Paleogene Indian monsoon climate vis-à-vis movement of the Indian plate, and the birth of the South Asian Monsoon

Coryphoid palms from the K-Pg boundary of central India and their biogeographical implications: Evidence from megafossil remains

“…Thus, the discovery of present and previously reported coryphoid palm megafossils of different organs, namely, leaves ( Srivastava et al., 2014 ; Roy et al., 2021 ), petioles ( Trivedi and Verma, 1981 ), leaf bases ( Bonde et al., 2000 ), stems ( Mahabale, 1958 ; Lakhanpal et al., 1979 ; Ambwani, 1983 ; Ambwani and Mehrotra, 1989 ; Gayakwad and Patil, 1989 ; Bonde et al., 2008 ; Khan et al., 2020a ) and fruits ( Bande et al., 1982 ) is generally taken to indicate a warm and humid tropical climate prevailed across what is now Madhya Pradesh, central India, during Late Cretaceous-early Paleocene times. This suggested paleoclimatic condition is also supported by earlier published qualitative paleoclimatic reconstruction using nearest living relatives (NLR) analysis ( Srivastava, 2010 ; Prasad et al., 2013 ; Srivastava and Srivastava, 2014 ; Manchester et al., 2016 ; Baas et al., 2017 ; Kapgate et al., 2017 ; Khan et al., 2019 ; Smith et al., 2021 ) and quantitative paleoclimatic data using Climate Leaf Analysis Multivariate Program (CLAMP) analysis ( Bhatia et al., 2021 ). The CLAMP-derived results based on physiognomic features of woody dicot fossil leaf assemblages of the same fossil locality predict a mean annual temperature of 23.4 °C ± 2.3 °C; a cold month mean temperature of 17.2 °C ± 3.5 °C, a warm month mean temperature of 28.1 °C ± 2.9 °C, a relative humidity of 75.6% ± 10.1% and a growing season precipitation of 2320 mm ± 643 mm during Late Cretaceous-early Paleocene time ( Bhatia et al., 2021 ).…”

“…This suggested paleoclimatic condition is also supported by earlier published qualitative paleoclimatic reconstruction using nearest living relatives (NLR) analysis ( Srivastava, 2010 ; Prasad et al., 2013 ; Srivastava and Srivastava, 2014 ; Manchester et al., 2016 ; Baas et al., 2017 ; Kapgate et al., 2017 ; Khan et al., 2019 ; Smith et al., 2021 ) and quantitative paleoclimatic data using Climate Leaf Analysis Multivariate Program (CLAMP) analysis ( Bhatia et al., 2021 ). The CLAMP-derived results based on physiognomic features of woody dicot fossil leaf assemblages of the same fossil locality predict a mean annual temperature of 23.4 °C ± 2.3 °C; a cold month mean temperature of 17.2 °C ± 3.5 °C, a warm month mean temperature of 28.1 °C ± 2.9 °C, a relative humidity of 75.6% ± 10.1% and a growing season precipitation of 2320 mm ± 643 mm during Late Cretaceous-early Paleocene time ( Bhatia et al., 2021 ).…”

“…In Madhya Pradesh, Coryphoideae is represented by only five genera ( Borassus , Livistona , Caryota , Trachycarpus and Phoenix ) with six species ( B. flabellifer , Chuniophoenix urens , Livistona chinensis , P. sylvestris , P. dactylifera and Trachycarpus fortune ) ( Singh et al., 2001 ; Singh, 2014 ). Here, we assume that the narrow distribution of coryphoid palms today is likely due to climate, ecology, and vegetation change since the Late Cretaceous ( Prasad et al., 2013 ; Bhatia et al., 2021 ).…”

PaleogeneFicusleaves from India and their implications for fig evolution and diversification

“…Plant diversity is shaped more strongly in space and time by climate than by any other factor (Harrison et al, 2020). Although the northward moving Indian plate was situated south of the equator in the early Paleocene (Chatterjee and Bajpai, 2017), and the northwestern part of the Indian subcontinent experienced a climate favoring tropical rainforests (Spicer et al, 2017; Shukla et al, 2018; Bhatia et al, 2021), the northward journey across the equator exposed the region to a range of changing conditions (Bhatia et al, 2021). This led to some taxa becoming extinct while a few managed to survive this environmental filter (Prasad et al, 2009; Shukla et al, 2018).…”

Progress and challenges in understanding Asian palaeogeography and monsoon evolution from the perspective of the plant fossil record

“…Clift, 2017;Clift et al, 2008;Coutand et al, 2014Coutand et al, , 2016Jain et al, 2009). Recent re-analyses of contained floras (Bhatia et al, 2021a;Khan et al, 2014Khan et al, , 2019, which have been known and studied for some while (Antal & Awasthi, 1993;Antal & Prasad, 1996a, b;1997, 1998Awasthi, 1992;Banerjee, 1996;Banerjee & Dasgupta, 1984Cautley, 1835;Khan & Bera, 2014a, b;Khan et al, 2011Khan et al, , 2014Khan et al, , 2015Khan et al, , 2016Khan et al, , 2017aPrasad, 1994a-c;Prasad & Pandey, 2008;Prasad & Tripathi, 2000) point to monsoon conditions having existed throughout the Neogene. What is not yet clear is when today's pronounced west to east increasing precipitation gradient developed along the Himalayan front, and what vegetation changes accompanied the drying in the west.…”