UPDATE 3-Telkom jumps, Vodafone slumps on Vodacom deal

(Adds Vodafone details, analyst reaction)

By Rebecca Harrison

JOHANNESBURG, Oct 10 (Reuters) - Shares in South Africa's Telkom (TKGJ.J) jumped almost 5 percent on Friday after Vodafone (VOD.L) offered to pay it 22.5 billion rand ($2.48 billion) for a controlling stake in mobile operator Vodacom.

The bid, which would give Vodafone control of South Africa's biggest mobile operator and a foothold in fast-growing African markets, valued Vodacom at 150 billion rand, matching the implied valuation of its previous bid for a smaller stake and despite market turmoil.

Telkom shares outpaced a sharp fall on the Johannesburg blue-chip index to climb almost 5 percent, trading 2.4 percent higher at 110.90 rand at 0950 GMT as investors welcomed a deal they had previously feared might collapse given stormy conditions.

But shares in Vodafone crashed an initial 16 percent in early trading in London, with analysts saying that the market turmoil of Thursday and Friday was not a good time to draw attention to a big deal.

Shares in the world's biggest mobile phone group by revenue were down 8.6 percent at 0952 GMT on Friday, compared to the FTSE 100 Index which was down 7.6 percent.

"In a normal world it would be a sensible thing to do and the price isn't outrageously high," John Davies of Dresdner Kleinwort told Reuters. "But in current markets you have to question whether spending big money is a good thing.

"It brings forward the time that you have to raise more money."