National Aeronautics and Space Administration Headquarters Washington, DC 20546-0001 Dr. H. Jay Melosh Lunar and Planetary Laboratory University of Arizona, Tucson Department of Planetary Science Tucson, AZ 85721-0440 Dear Dr. Melosh: Thank you for submitting the research proposal entitled ''Investigations of tectonic ridges in the northern plains of Mars ising MOLA data, theoretical models, and Viking and MOC imagery'' to the NASA Headquarters Mars Global Surveyor Data Analysis Program (MGSDAP) in response to NRA OO-OSS-OI (ROSS-200). l regret to inform you that your proposal was not selected for funding. Of the 93 proposals submitted to the MGSDAP a total of 47 Solicited Full Proposals were selected for funding. Each Solicited Full proposal is reviewed by several external and panel reviewers prior to the MGSDAP Review Panel meeting. During the panel meeting each proposal is discussed at length and rated as to the scientific merit, relevance, and cost effectiveness of the proposal with respect to the objectives of the MGSDAP. It is the panel's consensus evaluation of a proposal that forms the primary basis for selection or rejection. The summary evaluation of your proposed research is enclosed for your information. It is hoped that this information may be useful to you in any future proposal submissions. If you have any questions concerning the evaluation of your proposal of the MGSDAP, my e-mail address is jboyce@hq.nasa.gov or you can contact me at (202) 358-0302. Sincerely, Joseph M. Boyce. Discipline Scientist Mars Data Analysis Program Research Program Management Division Office of Space Science Enclosure NASA OSS Review Panel Mars Global Surveyor Data Analysis Program Consensus Review Date; April 4, 2001 PI and Affiliation: Jay Melosh/University of Arizona Proposal Number: NRA 00-O1-MDAP-035 Short Title: Investigations of tectonic ridges in the northern plains of Mars All proposals and reviews are proprietary and should be handled by the reviewer in a confidential manner. Comments on this page may be transmitted anonymously to the proposer. 1) SUMMARY OF RESEARCH OBJECTIVES. The proposed research focuses on the network of ridges in the northern plains of Mars that have been interpreted to be akin to wrinkle ridges. The investigation of these ridges will involve mapping their locations and describing their characteristics using MOLA data. The strain recorded by the tectonic ridges will be estimated. Their locations and estimates of strain will be compared with existing geophysical models that predict the magnitude and direction of stresses n the marxian lithosphere. Ridges in the northern plains that have been suggested as possible shorelines of an ancient ocean will be analyzed to determine if they fall on an equipotential urbane. Fine-scale structures associated with the ridges will be sought using Viking Orbiter and MOC images. Subdued craters in the northern plains will be examined using MOLA data to evaluate the depositional history. Finally, finite element modeling will be used to refine Geophysical models of stresses in the northern plains. 2) SUMMARY OF EVALUATIONS. Describe the proposal according to (1) Intrinsic Merit (discuss strengths and weaknesses); (2) Relevance to NASA Objectives (evaluate the likelihood that the results of the proposed work will contribute positively to NASA s goals and strategic plan), and (3) Cost Effectiveness (measure the balance between the requested budget, the value of the results/products, and the importance or relevance to current NASA objectives). Intrinsic Merit The pervasive occurrence of ridges in the northern lowlands revealed by MOLA data is one of the more interesting and surprising results of MGS mission. The proposed research would.address a number of important questions about the nature and origin of the ridges and would help further constrain the origin of this enigmatic region. The team assembled for the investigation is outstanding and amply qualified to conduct the geophysical modeling. There is no question that these ridges merit further investigation. The greatest weakness of the proposal is the lack of details provided on how the PI and team will accomplish the stated goals. Determining the strain, for example, is not a straightforward exercise because it appears that these ridges have been partially (and in some cases completely) buried by sediments. If this is the case, using topography to determine the shortening across the ridges will result in a significant underestimate of the strain. Models involving isostatic adjustment and flexural loading, while in good agreement with the locations and orientations of tectonic features in the Tharsis region, fail to account for the timing of deformation Thus a comparison of the ridges with stresses predicted by these models will be of limited benefit. Also, no details are given on how finite element modeling will help overcome the problems with the analytical models. All the interpretations of the ridges are made solely on MOLA topography. Available images should be examined before any conclusions are made about whether ridges are related to shorelines, etc. Finally, no reference is made to other ongoing investigations of the tectonic significance of the ridges. Relevance to NASA Objectives (evaluate the likelihood that the results of the proposed work will contribute positively to NASA s goals and strategic plan) or indicate No Relevance. The proposed investigation is very relevant to NASA s planetary program in general, and MDAP in particular. Cost Effectiveness The cost of the study is very reasonable, mostly covering graduate student costs. (3) COMMENTS AND SUGGESTIONS FOR THE PROPOSER. Adherence to these comments does not constitute a guarantee of future funding. The proposal lacks detailed descriptions of how the work will be accomplished. Also, some preliminary results would be very helpful in evaluating the potential success of the proposed efforts. The work of others investigating the tectonic significance of these ridges should be referenced. In examining the thickness of the deposits in the northern plains, it is suggested that the depth/diameter/rim height relations established by Garvin et al. from MOLA data be used. Since the requested funding is largely to support a graduate student (P. Withers), the proposal might be a strong candidate for the Graduate Research in Planetary Science program.