Keywords

1 Introduction

The Continental ice of Antarctica is separated by the Transantarctic Mountains and created two unequal ice sheets. The West Antarctica Ice Sheet is much smaller than the East Antarctica Ice Sheet (EAIS). The EAIS covering a vast tract of a continental area is an enormous ice mass on the earth's surface (Stonehouse 2002). The EAIS is comprised of several domes (e.g. Dome Fuji, Dome Argus, Dome Circe), reaching > 4.8 km of thickness near Dome Circe and estimated total grounded ice volume is 21.76 × 106 km3 (Lythe and Vaughan 2001; Fretwell et al. 2013; Mackintosh et al. 2014). The EAIS is divided into different parts (e.g., Dronning Maud Land (DML), Enderby Land, Mac. Robertson Land, Wilkes Land, George V Land) based on the continental plateau and regional slope, where mountain chains obstruct large tract of the ice sheet. The EAIS is considered stable than the West Antarctica Ice Sheet and Greenland Ice Sheet; however, recent studies differ (Pingree et al. 2011; Mackintosh et al. 2014). The volume of EAIS is comparable to ~ 53 m of mean seal level (Lythe and Vaughan 2001; Fretwell et al. 2013; Mackintosh et al. 2014); therefore, a minor change in the volume will have a more significant impact on the global sea level. Many unanswered questions about the processes and timescale of the formation and existence of ice sheets in Antarctica. The Continental ice sheet plays a vital role in controlling the earth's climate. Climate modelling suggests that the concentration of CO2 in the atmosphere is the foremost process for stabilising Antarctica's ice sheet (DeConto and Pollard 2003; Huber et al. 2004; Pollard and DeConto 2009). However, fewer attempts have been made to understand the response of post industrialisation rapid increase of atmospheric CO2 on ice sheets. Reconstruction of the last 50 years showed significant warming over West Antarctica (0.1 °C per 10 years) and East Antarctica parts (Steig et al. 2009). Paleoglaciation studies on million years' timescale suggest a decrease in the EAIS thickness (Fogwill et al. 2004; Fink et al. 2006; Huang et al. 2008; Strasky et al. 2009; Kong et al. 2010; Di Nicola et al. 2009, 2012; Altmaier et al. 2010; Liu et al. 2010; Lilly et al. 2010). The extent of this decrease and its impact on the global climate are ambiguous. Also, the nature of glacio-eustatic rise, for example, a rapid rise in sea level due to meltwater pulse during the last glacial maximum (LGM), is poorly understood (Clark et al. 2002; Peltier, 2005; Mackintosh et al. 2014). Proxy records from ice cores provide precise and direct methods to analyse Antarctic climate change (Legrand and Mayewski 1997; EPICA Community Members 2006; Mayewski et al. 2009). A continuous record of paleo-temperature and atmospheric compositions is established based on stable isotope study on ice core samples. The most extended history is established up to 800,000 years from Dome Circe (Parrenin et al. 2007). Looking at the vastness of the EAIS and diverse surface and subsurface features, it is difficult to generalise the change observed at one place to the entire ice sheet as the ice sheet's response to the climate change varies with regions. Therefore, each region's glacial history needs to be evaluated using multiple proxies and synthesised for EAIS to have a comprehensive picture at a continental scale. Several studies have been carried out to understand the glacial history based on the available landforms; sediment archives from the lake, coastal and offshore area; ice core data; terrestrial cosmogenic radionuclide (TCN) studies on ‘oasis’ (ice-free region), nunatak, mountains and glacial debris. In this chapter, the emphasis is given to the Dronning Maud Land region's glacial history based on the study conducted using cosmogenic radionuclides as a proxy.

Cosmogenic radionuclides (CRN) dating techniques have brought a revolution in studying the geomorphic and landscape evolution and the rate at which these processes act on the earth's surface. When the secondary cosmic ray interacts with the rock surface, radionuclides are formed in situ due to spallation reaction. These in situ produced CRNs are used for surface exposure dating. Glacial chronology from thousands to million years is established based on CRN surface exposure ages of glacial landforms, boulders and moraines (Nishiizumi 1993). In a similar timescale, the burial age of sediments or till depositions using CRN provides a chronology for glacial advancement or retreat. Like other methods, this technique has some limitations; however, these limitations can be quickly hindered with detailed field observations, proper sampling strategy and multiple nuclide selections. This age helps to develop the glacial models for ice sheet and valley glaciers. CRN surface exposure dating is only helpful in the ice-free area, mountains, and nunataks present within the ice sheet. In the EAIS, only 1–2% of the site is ice-free and generally found in the coastal zones called ‘Oasis' or within Mountain chains. Ages obtained from CRN like 14C from sediment archive also help understand the paleoclimate and glacial history. Several studies were carried out in Dronning Maud Land to understand the glacial history based on CRNs. The literature was reviewed to reconstruct a glacial chronology for the entire region and address a few unanswered questions for future research scope.

1.1 History of Antarctica Glaciation

The ice sheet in Antarctica prevailed since the middle of Tertiary about 35 million years ago, and it is generally agreed that it reached east Antarctica by the Eocene and Oligocene (Barrett et al. 1991, Hambrey et al. 1989; Birkenmayer 1987, 1991; Denton et al. 1991; Prentice and Mathews 1988; Barrera and Huber 1993). However, the commencement and the timing of glaciation required further evaluation. The reconstruction of ice-sheet extent and volume is based on the ocean drilling programmes (ODP), where clay minerals, stable oxygen isotopic concentrations and sediment analysis were carried out on samples collected from the offshore core. Antarctic glaciation's commencement in the middle of Tertiary was possible with the Gondwana breakup, drifting of Antarctica towards poles and formation of ocean gateways or opening of "Darke Passage" (Kennett 1977). Isolation of Antarctica and the development of circumpolar current subsequently led to the cooling and glaciation. Another model suggests that the Antarctica glaciation was initiated due to lower CO2 concentration in the atmosphere followed by a permanent ice cap due to further lowering CO2 to a threshold value (DeConto and Pollard 2003; Altmaier et al. 2010). The results from ODP show subtropical to temperate climates on Dronning Maud Land during Late Cretaceous (Kennett and Barker 1990). Data from the Weddell Sea suggested that Palaeocene's the warmest period (Kennett and Stott 1990; Robert and Kennett 1994). There are no records of ice sheet existence in the Late Cretaceous or Early Tertiary; however, fluctuations of ice sheets in east Antarctica have been reported (Anderson 1999). There was an increase in the 18O concentrations in the deep-sea records during the Eocene period, indicating the growth of ice sheets in Antarctica (Prentice and Mathews 1988, Denton et al. 1991; Abreu and Anderson 1998). Evidence supports ice sheets in east Antarctica during the Oligocene and the spreading of ice in the Ross Sea during Late Oligocene (Denton et al. 1991; Hambrey et al. 1991). However, ice sheet occurrences in west Antarctica are unknown (Birkenmajer 1998; Anderson 1999). Based on the fossil record, earlier studies proposed that temporary large-scale retreat of EAIS during Pliocene (Webb and Harwood 1987); however, the recent studies based on field evidence and numeric modelling do not support the retreat and suggest a stable EAIS during Pliocene (Denton et al. 1984; Sugden et al. 1995; Pollard and DeConto 2009; Altmaier et al. 2010).

1.2 Present-Day Scenario of Antarctica Ice Sheet

The grounding line is an essential indicator of ice sheets' instability, as their changes depict the flow of ice and imbalances with the surrounding ocean. Ocean driven forces have melted various Antarctic glaciers, which have retreated the grounding line rapidly. However, there are limited records to measure imbalance. Between 2010 to 2016, retreat in grounding lines in east Antarctica (3%), Antarctic Peninsula (10%) and West Antarctica (22%) were recorded (Konrad et al. 2018). It has been shown that the retreat has been very swift (25 m yr−1). The loss of grounded ice area has been around 1463 ± 791 km2 (Konrad et al. 2018). Satellite altimeter to measure the ice elevation and geometry of the ice were combined with tracking the grounding line movement. The fastest rates have been seen in the Amundsen Sea, while in Pine Island, the grounding line has stabilised possibly due to reduced ocean forcing. According to the ice geometry and satellite measurements, the retreat of grounding lines in west Antarctica, East Antarctica and Antarctica peninsula has been faster after the post-glacial event.

Variations in grounded ice sheets appear due to differences in meltwater runoff, discharge of ice in the ocean and snow accumulation at the surface (Rignot et al. 2011). There has been a reduction in ice thickness in recent times, which has disturbed ice's inland flow. Various satellite techniques complemented with the field measurements and mass balance model have been developed to estimate ice sheet masses' variations (Zwally et al. 2012). It has shown that 2720 ± 1390 billion tonnes of ice have been lost from Antarctica during from 1992–2017, increasing the sea level by 7.6 ± 3.9 mm. By this period in west Antarctica, melting has increased from 53 ± 29 to 159 ± 26 Billion tonnes per year. However, there are uncertainties in the models showing again in surface mass balance with an average being 5 ± 46 billion tonnes per year (Shepherd et al. 2018).

1.3 Glacial History: Evidence from Ice Cores

Antarctica's Ice cores indicate changes in the ice volume from the past 4 million years (Petit et al. 1997). Records from the Vostok show a well-built correlation with global ice records. This shows a link between the ice sheets of the northern and southern hemispheres (Petit et al. 1997). However, there are variations in climate and glacial history of Late Quaternary obtained from ice core, terrestrial, offshore records (Jouzel et al. 1987; Petit et al. 1997; Ingólfsson 1998; Anderson 1999; Ingólfsson and Hjort 1999). During the last glacial maxima (LGM), the east Antarctica domes were thinner than the present because the accumulation rates were lower (Jouzel et al. 1989; Siddall et al. 2012). These observations are based on the ice sheet models and the ice core data. However, these changes in ice thickness are poorly known. Ice cores data used to reconstruct elevation using gas content of the bubbles trapped within ice and ice flow models to constraint the accumulation rates. Both the methods have uncertainties in their results; therefore, they should be used carefully for reconstructing glacial event. However, the obtained records of the past ice thickness are consistent with these methods.

2 Dronning Maud Land (DML)

Dronning Maud land is a region in East Antarctica covering an area of 2.7 × 106 km2 (Fig. 1). In this region, different countries have established permanent research stations operational year-round or sessional to study geology, geodetic, glaciology, geophysics and atmospheric phenomena etc. Some of the essential stations are Maitri (India), Aboa (Finland); Weasands (Sweden); Troll and Tor (Norway), Princess Elisabeth Base (Belgium), Neumayer-Station III and Kohnen (Germany), Novolazarevskaya Station (Russia), SANAE IV (South Africa), Asuka, Showa and Dome Fuji Station (Japan).

Fig. 1
figure 1

Location of Dronning Maud Land, East Antarctica and name of the mountain ranges and ice-free regions are given in the diagram (Modified after Mackintosh et al. 2014). Dotted lines indicate the movement of ice mass and slope reduce toward the coastal region

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The Dronning Maud land is dominated by Precambrian gneiss formed between 1 to 1.2 Ga. The mountains in the area are characterised by granitic and crystalline rocks that probably formed 500 to 600 Ma ago during the assemblage of Gondwana land. Younger sedimentary and volcanic rocks are found in the western parts of the region. Borg Massif guards the ice sheet over DML in the west and Yamato Mountain in the east (Pattyn et al. 2010; Mackintosh et al. 2014). The region has thick ice sheets that show downslope towards the coastal part from the continental plateau. Various researchers studied several mountain ranges, nunatak and oasis (ice-free area) located within the DML ice sheet to reconstruct the glacial history of EAIS. The important mountain ranges from west to east are Vestfjella, Heimefrontfjella, Ahlmannryggen, Gjelsvikfjella, Wohlthat Massif (includes Peterman Range, Insel Range, Gruber Mountains and Humboldt Mountains), DallmannBergeandPetermannKetten mountains (south of Wohlthat Massif), and SørRondane Mountains (Fig. 1). Among ice-free areas, Schirmacher oasis, Untersee oasis and coastal oasis in the Lützow-Holm Bay (towards eastern margin of DML ice sheet) were extensively studied for geomorphology, paleoclimate and glacial history. These ice-free regions are home to numerous lakes, Roche Moutonnée, a fossil glacier track filled with boulders, till and moraine deposits.

Striated surfaces and bedrock from nunatak and Roche Moutonnée, erratic's and boulders from fossil glaciers track provide ample opportunities to use cosmogenic radionuclides to measure the surface exposure age, and it can be used for understanding the variation of ice thickness and glacial history. During glacier retreat or thinning and shrinking of the ice sheet, bedrock or boulders are exposed to the cosmic ray, and in situ, cosmogenic radionuclides are produced. Although target nuclides are present in all the rock-forming minerals, quartz is used to measure radionuclides' concentration. The production and decay rate of cosmogenic radionuclides is well established; hence, it calculates bedrock's surface exposure age or boulder. Similarly, sediment archives from the lake deposits and offshore region are used to know the time of deposition using cosmogenic radionuclides, indicating paleoclimate, transport mechanism and paleoenvironmental setting.

2.1 Applications of Cosmogenic Radionuclides (CRN)

Earth and its atmosphere continuously receive solar and galactic cosmic rays. These primary cosmic rays are mainly high-energy (0.01-102 GeV) protons and alpha particles. Upon entering into the earth's atmosphere, direct cosmic rays interact with the nuclei of atmospheric elements and produce a cascade of lower energy secondary cosmic rays (mainly neutrons). These secondary cosmic rays further interact with the elements present in the atmosphere and on the earth surface, and in spallation reaction, radioactive isotopes (also called radionuclides) are produced. Radionuclides produced on the earth surface and top layers are called in-situ had CRN (such as 10Be, 26Al, 21Ne etc.) and those made in the atmosphere are called garden variety CRN.

Solar cosmic rays are of lower energies and get easily deflected by the geomagnetic field. The atmosphere further causes attenuation. Even at high latitudes, where the geomagnetic deflection is less, solar cosmic rays can penetrate only the topmost layers of the atmosphere and hardly reach the earth's surface their low energy.

Galactic cosmic rays (originating outside the solar system from supernova explosions) are of higher energies and significantly contribute to the in-situ production of 10Be and 26Al. Due to higher energies, GCRs are only partially shielded by the geomagnetic field and reaches earth surfaces after penetrating the whole atmosphere. Major in-situ production channels of 10Be and 26Al on the earth surface are by spallation of neutrons with oxygen (Fig. 2) and silicon, respectively, [16O (n, 4p3n)10Be, 28Si (n, p 2n) 26Al present in quartz mineral].

In-situ 10Be production rate at sea level and latitude ≥60°, in the rocks having exposure ages ranging from 11 ka to 4 Ma is estimated between 5.8 to 6.4 atoms per year per gm of quartz (Kubik et al 1998). While, the production rate of 26Al in SiO2 in terrestrial rocks at sea level and latitude > 60° is about 37 atoms per year per gm of quartz (Kubik et al. 1998), and increases rapidly with altitude to 374 atoms per year per gm of quartz at 3.34 km altitude at 44° N (Nishiizumi et al. 1989).

In areas where the inherited and independent ages coexist, magnitude, rate, and spatial patterns can be revealed from single cosmogenic nuclides. However, by applying two radionuclides (10Be and 26Al) with different half-lives on the same samples, uplift rates can be determined with greater accuracy and confidence (Tuniz 2001). These provide a model that links the erosion and ice dynamics processes. The error ranges lie in ± 5 – 10% for the surface exposure dating, including systematic and analytical error. CRNs like 10Be, 26Al and 14C are used suitably for the burial age of the sediments/pebble/cobbles depending upon the landforms, local setting and type of sediments.

Fig. 2
figure 2

Showing the in-situ production of Beryllium-10 and Aluminium-26 and production of carbon-14 in the atmosphere (Tuniz 2001; Willenbring and von Blanckenburg 2010)

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2.2 Measurement of CRNs

Cosmogenic 10Be (T1/2 = 1.38 Ma) and 26Al (T1/2 = 0.72 Ma) in the geological samples are found at a deficient level, and their isotopic ratios (10Be/9Be and 26Al/27Al) ranges between 10–11 to 10–15. The measurement of such trace CRNs is challenging and beyond the measurement capabilities of conventional mass spectrometric methods insensitivities and isobaric interferences. Accelerator Mass Spectrometry, in which an individual atom of CRN is counted after removing isobaric and isotopic interferences, is the technique, which can perform such ultrasensitive measurements with very high precision (Kumar et al. 2011, 2014, 2015). The sample processing and AMS measurement methods are described in various references (Kumar et al. 2011, 2014, 2015).

3 Glacial History of Dronning Maud Land (DML)

Various studies like field observations, ice thickness measurement based on echo sounder, GPR, gravimeter; proxy-based analysis, ice core data, modelling and simulations were used to understand the glacial history of the Droning Maud Land. Most of the field-based studies and data collections were conducted in the continental and ice-free regions as oasis located in the low-lying coastal areas and marginal mountainous areas (Pattyn et al. 1992). The region's present glacial geomorphology is developed due to polycyclic glaciation and deglaciation phases, where deglaciation occurred frequently and for longer durations (Pattyn et al. 1992). Base on-field evidence around the Sor Rondane Mountain region and flow line model, Pattyn et al. (1992) reported that ice thickness was increased by 300–400 m during the last glacial maximum. The previous study based on the ice age model using glaciological and geomorphological evidence also suggests a similar increase in ice thickness of 400 m (Hirakawa and Moriwaki 1990). Based on the ice age simulation, it has been reported that the Grounding line of the Antarctica ice sheet was advanced by 20 km and 100 m thickening of polar ice plateau during that period (Pattyn et al. 1992). The ice cover of DML and EAIS responded slowly to climate change, as reported by Pollard and Deconto (2009) and Huybrechts (1993). In the longer time scale, the recent study using surface exposure dating of nunatak (south-east of Wohlthat Massif) suggest that between 0.75 to 3.57 Ma, the ice surface lowered at a rate less than 1 mm/year (Strub et al. 2015). The authors also did not rule out the possibility of exhumation as it can bring the nunatak above the ice surface. Previous surface exposure study from the same region suggests that Wohlthat Massif was exposed between 1 to 4 Ma ago (Altmaier et al. 2010). However, Strub et al. (2015) argued that this could be due to the thickness of the ice sheet as it was thicker (200–400 m) than today until ~ 0.5 Ma ago or due to the upliftment of that region. Many instance results from recent studies on other parts of the EAIS and for a different period do not converge. Therefore, the glacial history of EAIS is debatable. The effort was made to reconstruct the deglaciation history of Antarctica ice sheet since the Last Glacial Maximum based on the available data from different part of Antarctica by 'The RAISED Consortium' et al. (2014), where a change of the ice thickness and the grounding line position for the different period were discussed. Whereas Mackintosh et al. 2014, described the glacial history for a different location and summarised the changes of EAIS since the Last Glacial Maximum. Previous studies based on the surface exposure ages and burial age of sediments using cosmogenic radionuclides like 14C, 10Be and 26Al were compiled (Table 1), and a sequence of glacial events was established.

Table 1 Cosmogenic radionuclide dating from Dronning Maud Land used for the chronological constraint of glacial history
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3.1 Holocene Period

From the DML region, sparse records from a few oases and nunataks projecting from the ice sheet provides limited information about glacial fluctuation during the Holocene period. Like most Antarctica parts, the grounding line of ice sheets in the DML region was either on the inner shelf or close to the present-day position by 5 ka (The RAISED Consortium et al. 2014). However, in the west part of DML, the grounding line was seaward at the Weddell Sea compared to the present-day position. In the Heimefrontfjella region snow, petrel nests position is lying between 30 and 230 m above the present-day surface, and 14C date of mumiyo sample from basal layer indicate that the since 8700 ± 40 yr B.P. (Lintinen and Nenonen 1997), top of the ice sheet was ~ 30 m above the present surface (Mackintosh et al. 2014). Similarly, mumiyo samples from Ahlmannryggen and Gjelsvikfjella ice-covered ridges in the western part of DML show 14C dates of Holocene age with oldest dates recorded 8330 ± 70 yr B.P. and 3730 ± 80 yr B.P., respectively (Steele and Hiller 1997). These dates considered to be the minimum age of deglaciation of that region. However, other 14C dates from Muhlig-Hafmannfjella, a nearby region, provides older dates and suggesting the thickness of EAIS is close to the present position before LGM (Steele and Hiller 1997; Mackintosh et al. 2014). In the Lützow-Holm Bay region (eastern part of DML), marine fossil samples from raised beach provided two clusters of 14C age, where a sample from Ongul island situated towards north shows ~33–50 ka age, and sample from Skarvsnes and Skallen peninsula towards south shows <7 ka age (Miura et al. 1998; Takada et al. 2003; Mackintosh et al. 2014).

Similarly, samples from other islands in the south show Holocene ages. It was inferred that during the late Pleistocene, EAIS was retreated from the northern part and did not advance during LGM. However, the ice sheet has withdrawn from the southern part after the LGM and region were ice-free during the Holocene. The difference in surface weathering in this area's northern and southern region supports the relative variation in the glaciation history. Another cosmogenic radionuclide dating confirms that the Skarvsnes peninsula had ~ 360 m ice sheet, and it has retreated between 10 and 6 ka ago (Yamane et al. 2011; Mackintosh et al. 2014). Erratic boulders from east Antarctica show that ice sheets reached the present configuration by this time. There was considerable thinning of ice sheets between 10 and 5 ka. The Lazarev Sea of east Antarctica has unearthed the processes that controlled the sedimentation over the past 10,000 yr during deglaciation. Lazarev Sea has distinct facies which reveal the environment of deposition with glaciomarine processes. These depositional sequences preserve the retreat of the ice history in this part of the continent. The minimum age of retreat of glaciers obtained from 14C dating is 1550 ± 70 yr B.P. (Gingele et al. 1997).

The dates were obtained from carbonate particles terrestrial areas were exposed by 5 ka. Some areas also indicate fluctuations during Holocene (Gingele et al. 1997). The Nivl Ice Shelf of the Lazarev Sea is situated north of Schirmacher Oasis (Fig. 1), central DML. Laminated sediments from the Nivl Ice Shelf, dated to be 11,140 ± 120 14C yr B.P. (Gingele et al. 1997) and suggesting deglaciation of continental shelf during early Holocene. Subsequently, proglacial lakes were formed in the Schirmacher oasis (Mackintosh et al. 2014). This ice retreat was continued, and further, Schirmacher Oasis was becoming ice-free, and the proglacial lake became landlocked lakes around 3 ka (Schwab 1998; Phartiyal et al. 2011). However, another study based on surface exposure dating using cosmogenic radionuclide dating and lake sediment dating suggest that Schirmacher oasis was ice-free before LGM (Altmaier et al. 2010).

The substantial recession of ice sheets in east Antarctica arose around 13 cal yrs B.P., and the retreat was swift in Holocene. In West Antarctica, the retreat began at 10 ka. The ice sheets retreated significantly in the eastern and western Antarctica peninsula by the 15 and 10 ka and reached the present state during the Holocene middle. While on the east side, it would have gone by 10 ka (Ingólfsson et al. 2004).

3.2 LGM and Post LGM

The time duration of LGM (Last Glacial Maximum) varies from place to place, and the global chronostratigraphy refers to the time of the event from c. 26.5 to 19 ka B.P. (Clark et al. 2009). The literature term LLGM (Local Last Glacial Maximum) is being used for a specific location (Clark et al. 2009) to explain the last glacial maxima that differ widely. However, global LGM is considered roughly around 20 ka. To avoid such ambiguity, 'The RAISED Consortium et al. (2014) explain Antarctica's glacial history in the different time slices such as 20 ka, 15 ka, 10 ka and 5 ka. Available data shows Antarctica Ice sheet was not at its maximum extent during LGM (Anderson et al. 2002) and shows local variations. The DML region of EAIS shows the variation in glacial history during the LGM period. The glacial-geological data and ice sheet model contradict EAIS elevation changes around the Weddell Sea region during LGM. This region's overall glacial history is diverse compared to other DML sites (Hillenbrand et al. 2012). As per the Weddell Sea marine sediment record, the grounding line's extent is nearly 100 km seaward during 21 ka than the present (Elverhøi 1981; Mackintosh et al. 2014). Several glacio-geomorphological studies were conducted in the Vestfjella, and Heimefrontfjella mountain ranges and some of the result on the past ice thickness and its timing are contradicting (Jonsson 1988; Lintinen 1996; Lintinen and Nenonen 1997; Hattestrand and Johansen 2005). As no chronological constraints are available from the region, based on the field observation like the position of striations and till depositions in the Vestfjella region, the thickness of the ice sheet during LGM was estimated to be 700 m thicker than the present (Hattestrand and Johansen 2005; Mackintosh et al. 2014). However, these results are not supported by the 14C dating of mumyio sample from this region and indicate that since 38,700 ± 1500 yr B.P., the region was ice-free (Thor and Low 2011). Based on the glacio-geomorphological evidence and surface weathering analysis in the Heimefrontfjella area, it has been contended that 100–200 m thicker ice sheet was present during LGM than today. The sediment core samples collected from few lakes situated on the Schirmacher Oasis shows that the region was covered with an ice sheet during LGM (Schwab 1998; Phartiyal et al. 2011); however, it is contradicted by other results. Based on the surface exposure dating using cosmogenic radionuclides in the SorRondane Mountain, it is inferred that the region had ~ 100 m thicker ice sheet during LGM than present-day. Studies on the nunataks from DML shows significantly less or no ice sheet thickening. Additionally, evidence from the ice-core and the ice-sheet model offers a thickness of the ice sheet was 100 m lower than the present during LGM (The RAISED Consortium et al. 2014) in the interior part of the ice sheet.

3.3 Pre LGM

Surface exposure dating using cosmogenic radionuclide from the Wohlthat Massif suggested that the thickness of EAIS has not changed significantly since 100 ka (Altmaier et al. 2010). Similarly, studies indicate that Sor-Rondane Mountain was ice-free since 4 Ma, and however, nunataks from the peripheral parts of this mountain range have become ice-free since 200 ka. Five phases of this region's deglaciation were established based on the surface weathering, where the last stage was dated using cosmogenic radionuclide to be 25 ka (Moriwaki et al. 1991; Nishiizumi et al. 1991; Moriwaki 1992; Ishizuka et al. 1993). There are no advances seen in Schirmacher and Untersee; however, dating and grain size distribution from Lazarev suggests that it may have advanced between 82 ka B.P. (Gingele et al. 1997). Ice sheets in Queen Maud Land were not stable and linked to the ice sheet's interior. There is evidence of changes in the central Antarctic ice sheet during this time scale. The maximum advancement in ice has been sampled from the high altitude Petermann Ketten Mountains. Areas like Untersee, Schussel, on the other hand, suggest that ice sheets were 400 m higher before 0.5 million years. From the data, the impression we get is the steady thinning of the ice sheets; this may be related to the global cooling, which began at the end of the Pliocene. This cooling would have lowered the precipitation rates and, subsequently, Antarctica's ice thickness (Raymo 1992). Other workers Welten et al. 2008 and Höfle 1989, have also supported this.

The evidence from east Antarctica indicates no advance in the ice thickening during the LGM, as is evident from the Sorrondane and Wohlthat Massif. There was a decrease in ice elevation in these areas, as supported by the ice core records. The ice coverage in the last 8 million years is exposed at the high altitude Petermann Ketten Mountains. On the other hand, the ice sheet in Wohlthat Massif had been 200–400 m higher, as shown by the exposure ages of Schussel, Dallmann Berge and Untersee samples. The Eckhorner indicates ice coverage did not exceed 300 m. In general, there is a decrease in ice thickness and exposure of rocks that were buried in ice. This is interpreted as a result of global cooling, which ended in the Pliocene (Raymo 1992). The retreat in the present ice level culminated approximately 0.1 Ma ago. During LGM, the ice level increase was enough to cover the Schirmacher Oasis, as evident from Dallmannberge. A higher concentration of cosmogenic nuclides represents lower rates of erosion from the Peterman Ketten Mountains. These low erosion rates are found in hyper-arid and cold climates. The dates obtained from this area were the first attempt.

4 Melt Water Pulse (MWP)

Several meltwater pulses (MWP) were recorded since the LGM period. There was about an 18 m increase in sea level due to MWP1a during 14.7 to 13.3 ka (Deschamps et al. 2012). The pattern in sea level rise indicates a considerable contribution from the Southern hemisphere. However, the recent data from ice sheet models and ice core records show that only 10 m of ice was locked equally to the eustatic level during LGM (Golledge et al. 2012; Whitehouse et al. 2012; Mackintosh et al. 2011). Mackintosh et al. 2011 suggest that the volume of EAIS increased by 1 m, excluding the embayments of Weddell and Ross seas which is equal to the eustatic level of LGM. This indicates a total 10% contribution from Antarctic ice sheets as shown by the ice sheet models (Golledge et al. 2012; Mackintosh et al. 2011; Whitehouse et al. 2012; Pollard and DeConto 2009). It is not straight forward to understand the contribution of EAIS to the MWP1a, as the volume of ice is small and deglaciation was slow and late. There is evidence of a small donation to MWP1a from Amery and Lambert (Verleyen et al. 2005). There is no clear evidence on how significantly EAIS contributed to MWP1a due to the lack of data or insufficient data constraining or modelling techniques, which needs to be assessed.

5 Marine Isotope Records

Marine isotope records are essential for understanding the Quaternary climate globally (Lisiecki and Raymo 2005; Golledge et al. 2012). Although isotopic records are also affected by the deep-water temperatures (Shackleton 1967), these records are used as a proxy since 1960 to decipher global ice volume. The LGM in Antarctica is not well established; however, it is assumed that it may have occurred during the marine isotope stage 2 (MIS-2). In east Antarctica, maximum extension occurred by 17 ka and 10.7 ka B.P. at Prydz and Mac's coasts. Robertson Land. In the Antarctic Peninsula, the LGM occurred after 30 ka B.P. (Sugden and Clapperton 1980). Recent studies suggest that the Wisconsin ice sheet would have formed by 20 to18 ka (Bentley and Anderson 1998), indicate ice sheets were higher before 35 ka.

In the same way, ice sheets in the Weddell Sea were higher before 26 ka. However, Hjort et al. (2003) indicate the maximum extension in ice occurred before MIS-3 in the western part of the Weddell Sea. Late Quaternary ice distribution suggests Antarctic sea ice in winter advanced towards the present polar zone by MIS-2. During MIS-3, there were several climatic warmings known as Dansgaar and Oeschgerevents (D.O.), between 60 and 27 ka. D.O. events are a period of transition from cold to mild conditions followed by the return of stadial conditions (Dansgaard et al. 1993). In MIS-3, D.O. events were regular is unclear why they were so frequent. These events were absent during the LGM. Ice cores from Greenland show the rise of 8–16 °C followed by a cooling period before the temperatures returned to stadial values. These transitions have also been indicted by the North Atlantic Ocean (Huber et al. 2006; North GRIP-Members 2004). Marine records suggest that interstadials had higher sea temperature and ocean deep ventilation than stadia. There is a scarcity of information on the east Antarctic ice sheet during MIS-3. Ice models suggest that EAIS expanded during MIS-3 in comparison to the Holocene. However, the field evidence contradicts the modelling evidence and indicates that ice sheets did not advance than the present. Cosmogenic results show that there were areas, which were ice-free for most of the marine isotope stage-3. The last glacial cold cycle has the most prolonged period at around 118 ka. Interglacial period MIS 5-e is at 115 ka (Shackleton et al. 2002 and 2003). The cold cycle of the last glacial had two various complex stages during MIS 4 and 2. Temperature and dust records of Antarctica also indicate this. The average temperature in Antarctica reached −10.2 °C and −10.6 °C for marine isotope stage 4 and 2. These two are divided by the warm interglacial of MIS-3. The millennial-scale variability indicated by Antarctic and Greenland ice core records (Blunier et al. 1998; Markle et al. 2017). Hughes et al. 2013 reported the asynchronies in the glacial cycles, mainly in Asia, where they advanced during the yearly glaciation cycle (Astakhov 2018; Larsen et al. 2006; Svendsen et al. 2004; Vorren et al. 2011). There is evidence of thicker ice sheets in Antarctica before LGM, while at the centre of east Antarctica, there was no thicker ice at LGM than at present (Lilly et al. 2010). Some marine oxygen records indicate the global volume of ice was higher in marine isotope stage 6 than MIS-2 (Roucoux et al. 2011; Shackleton 1987). This is supported by Shakun et al. (2015) for global sea level. However, data obtained by Lisiecki and Raymo (2005) show that MIS-2 has higher 18O records than MIS-6. However, temperature effects may hide the ice volume because, during MIS-6, sea surface temperatures were warmer than MIS-5d-2. This has allowed the supply of moisture to drive the extent of ice masses more in other glacial periods. The distribution of ice before LGM was different from LGM. Eurasia had more ice masses before LGM. Similarly, North America had smaller ice masses before LGM compared to the LGM (Rohling et al. 2017). The pre-glacial maximum peak occurred around 140 ka (Colleoni et al. 2016; Stirling et al. 1998; Raisbeck et al. 2014).

6 Summary

Grounding line in most Antarctica parts was near the present shelf before 20 ka except in the Ross and the Weddell Sea. Besides, the extent of ice reached before 20 ka in some places while recession had started at this time (Hillenbrand et al. 2014). The geological and marine data shows considerable ice by 20 ka in the Weddell Sea's continental shelf. From the east and west Antarctica, the data is limited. Half of the ice that has been grounded in the Ross Sea comes from east Antarctica (Anderson et al. 2014). Radiocarbon dates show that the recession of ice sheets started before the LGM. Some parts of East Antarctica reached the present shelf margin by this time (Mackintosh et al. 2014). The sediments of the MIS-3 suggest that several areas were ice-free at this time. Likewise, in Dronning Maud land, there are sparse or no evidence of ice thickening during LGM. Ice sheet and ice core models show the ice domes were possibly 100 m lower than at present. Striated bedrock, till, and organic deposits like mumiyo provide evidence for changes in the past and the dynamics of EAIS. Various workers' analysis was combined, which showed that a 600 m high ice sheet existed 4 million years ago, decreasing continuously to the present day. The question is how much mean sea level is expected to rise under different climatic scenario's (Bindoff et al. 2007). By reconstructing the glacial history of EAIS could help address these questions and understand the more direct dates required from this region. Surface exposure dating using cosmogenic radionuclide proved to be a potential technique to date the deglaciation phase. From Dronning Maud Land, more dates need to be generated to establish a detailed glacial chronology. The work is in progress to establish chronology in DML with the sample collected during 36th Indian Scientific Expedition to Antarctica by one of the authors.