* CEO Ramirez Martiarena resigns after 3 years in post
* Group veteran Ian McIntosh named CEO
* Federico Cerisoli new CFO after Armand Lumens leaves
* Dreyfus has been grappling with tough market cycle (Adds details, background)
By Gus Trompiz
PARIS, Sept 25 (Reuters) - Louis Dreyfus Company announced the surprise departures of its chief executive and head of finance on Tuesday, triggering another reshuffle at the commodities giant as it strives to recover from weak agricultural markets.
The group said in a statement that Gonzalo Ramirez Martiarena had resigned as CEO after three years in the post to pursue other opportunities, and would be replaced with immediate effect by Ian McIntosh, previously chief strategy officer.
British national McIntosh, 57, has worked for the family-owned group for over 30 years and became strategy chief earlier this year in a previous round of management changes.
Louis Dreyfus also said Federico Cerisoli, previously deputy chief financial officer (CFO), would become group CFO after Armand Lumens decided to leave for personal reasons following less than two years in the post.
A spokeswoman for Louis Dreyfus said the resignations of Ramirez and Lumens were "unrelated and coincidental", and were not connected to the group's first-half results, due to be published on Oct. 8.
She declined to comment further on the departures.
Dreyfus, the "D" of the so-called 'ABCD' quartet of agricultural commodity majors that also includes Archer Daniels Midland, Bunge and Cargill, has seen a series of management changes in recent years under chairperson and majority shareholder Margarita Louis-Dreyfus.
Those changes have occurred in the midst of a general downturn in agricultural markets that has prompted multinational firms to restructure operations and fuelled speculation about industry consolidation. Louis Dreyfus has sold its metal trading business and part of its fertiliser activities.
The CEO change took grain market participants by surprise, but some welcomed McIntosh as an experienced choice.
"He's always worked for the firm so he's in a good position to be able to turn things around," said one industry source who previously worked for Louis Dreyfus.
The privately-held group reported higher profits for 2017, citing progress in restructuring efforts, but excluding its divested metals unit full-year net profit declined.
Some peers like Cargill have seen earnings grow as they have shifted away from traditional trading towards activities such as meat processing and food ingredients.
Louis Dreyfus is also facing financial pressure after injecting $1 billion this year into debt-laden Brazilian sugar unit Biosev, while Margarita Louis-Dreyfus is due to buy out a chunk of shares from minority family shareholders in what could cost at least $800 million.
In the recent management turnover at Louis Dreyfus, several senior traders, led by its former global head of grains, left the group together a year ago to join a trading firm set up by other members of the Louis Dreyfus family.
Outgoing CEO Ramirez had been promoted to the post in 2015 after a protracted recruitment process that saw Louis Dreyfus appoint Mayo Schmidt before failing to agree terms with the former head of Canadian grain handler Viterra.
In Tuesday's statement, Margarita Louis-Dreyfus said Ramirez had "successfully fulfilled his mandate of putting the group in its current solid financial position and creating the conditions for the company's next phase of growth." (Reporting by Gus Trompiz; Additional reporting by Maha El Dahan and Sybille de La Hamaide; Editing by Veronica Brown and Mark Potter)