Under scientific collaborations, resource sharing tends to be highly dynamic and often ad hoc. The dynamic characteristics and sharing patterns of ad-hoc collaborative sharing impose a need for comprehensive and flexible approaches to reflect and cope with the unique access control requirements associated with the ad-hoc collaboration. In this paper, we propose a role-based access management framework to enable secure resource sharing, especially focusing on the digital information sharing in the heterogeneous scientific collaboration environments. Our framework incorporates role-based approach to address distributed access control, delegation and dissemination control involved in the resource sharing within such environments. A set of XACML-based policy schemas is proposed to specify policies on our framework. To demonstrate the feasibility of our framework, we design and implement a proof-of-concept prototype system called ShareEnabler, which is based on a peer-to-peer information sharing toolkit developed by Lawrence Berkeley National Laboratory.