Abstract <p>The mafic sills intruding into the dolostone in the uppermost part of the Vempalle Formation, Cuddapah Supergroup, have caused extensive metasomatism in the dolostone, resulting in serpentinisation and hydrothermal chrysotile mineralisation in the Pulivendla asbestos belt. Three different coloured varieties of serpentine, namely black, green, and yellow serpentine, have developed successively away from the mafic sill-dolostone contact. These serpentines belong to the lizardite variety and occur in the form of massive bands, irregular replacement patches, and stylolite fills in dolostone. Due to high <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12040_2025_2562_Article_IEq1.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="37" /> </InlineMediaObject> <EquationSource Format="TEX">\(\text{X}_{\text{H}_{2}\text{O}}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mtext>X</mtext> <mrow> <msub> <mtext>H</mtext> <mn>2</mn> </msub> <mtext>O</mtext> </mrow> </msub> </math></EquationSource> </InlineEquation> activity and lesser silica activity, in some portions of dolostone, brucite has formed in excess of lizardite. This is the first report of brucite mineralisation from this asbestos belt. Major and trace element data indicate a greater contribution from the mafic sill for the formation of black serpentine and a greater role of dolostone in the formation of yellow and green serpentine. A simple mixing model of the ¹⁴³Nd/¹⁴⁴Nd values also supports the contribution of the mafic sill and carbonate in the proportion of 60:40 in the formation of black serpentine. Variation in the concentration of transition metals Fe, V, Cr, Co and Ni is possibly responsible for the development of serpentine having different colours. Serpentinised dolostone commonly shows depletion in <i>δ</i>¹³C and <i>δ</i>¹⁸O values ranging from –1.43 to –0.76‰ and –18.01 to –17.06‰, respectively, compared to those of unaltered dolostone (<i>δ</i>¹³C: 0.35–0.97‰ and <i>δ</i>¹⁸O: –7.11 to –8.75‰). The depletion in <i>δ</i>¹³C and <i>δ</i>¹⁸O values in the serpentinised dolostone is inferred to be caused by decarbonation and interaction with the mafic magma. Serpentinisation of dolostone was accompanied by extensive fracturing and development of stylolites, and followed by hydrothermal fluid flow when some of the early formed serpentines were dissolved in the hydrothermal fluid and re-precipitated as chrysotile filling fractures and stylolites.</p> Research highlights <p><UnorderedList Mark="Bullet"> <ItemContent> <p>Dolostone in the uppermost part of Vempalle Formation was serpentinised upon emplacement of mafic sill.</p> </ItemContent> <ItemContent> <p>Chrysotile mineralisation occurred after the serpentinisation of dolostone by dissolution and re-precipitation of previously formed lizardite variety of serpentine.</p> </ItemContent> <ItemContent> <p>Incidence of brucite mineralisation in serpentinised dolostone of Pulivendla asbestos belt is identified and reported for the first time.</p> </ItemContent> </UnorderedList></p>