INVERTED CHANNELS ARE COMMON GEOMORPHIC FEATURES ON MARS; THEY RESEMBLE SINUOUS OR BRANCHING RIVERS IN PLAN-VIEW BUT STAND IN POSITIVE RELIEF AS RIDGES. THEY ARE ONE OF THE PRIMARY LANDFORMS USED TO RECONSTRUCT ANCIENT RIVER PROCESSES ON MARS BECAUSE THEY ARE READILY DETECTABLE FROM ORBIT AND ARE WIDESPREAD ACROSS MARS INCLUDING AT THE MAJORITY OF CANDIDATE LANDING SITES FOR MARS 2020 AND EXOMARS ROVERS. HOWEVER WE LACK A MECHANISTIC UNDERSTANDING OF THEIR FORMATION AND SIGNIFICANT DEBATE EXISTS CONCERNING THEIR PROPER INTERPRETATION IN CASES YIELDING INTERPRETATIONS OF FLOW IN OPPOSITE DIRECTIONS AND WATER DISCHARGES DIFFERING BY SEVERAL ORDERS OF MAGNITUDE. ROVERS HAVE YET TO VISIT AN INVERTED CHANNEL ON MARS AND THEREFORE WE LACK THE NECESSARY IN-SITU SEDIMENTOLOGICAL OBSERVATIONS TO PROPERLY RECONSTRUCT PALEOHYDROLOGY FOR VERIFYING THE ORBITAL RECONSTRUCTIONS. IN-SITU INVESTIGATIONS OF INVERTED CHANNELS ON EARTH CAN PARTLY FILL THIS KNOWLEDGE GAP AND ALLOW US TO BUILD BETTER METHODS FOR QUANTIFYING THE PALEO-HYDROLOGY OF ANCIENT RIVERS ON MARS FROM ORBITAL OBSERVATIONS ALONE. THE GOAL OF THIS PROJECT IS TO DEVELOP TEST AND IMPLEMENT A METHOD FOR QUANTITATIVE INTERPRETATION OF ANCIENT MARTIAN RIVER NETWORKS AND THEIR DEPOSITS FROM ORBITAL OBSERVATIONS OF INVERTED CHANNELS ON MARS. WE WILL ACHIEVE OUR PROPOSED GOAL THROUGH COMPLETION OF THREE MAIN TASKS: (1) MEASURE RIDGE DIMENSIONS (BREADTH THICKNESS SLOPE RELIEF) AND SEDIMENTOLOGY (FACIES CROSS-BEDDING PALEOHYDROLOGY) AT INVERTED CHANNELS IN UTAH AND SPAIN. (2) USE MEASUREMENTS FROM TASK 1 TO TEST THE TWO COMMON HYPOTHESES FOR INVERTED CHANNEL FORMATION WHETHER RIDGES ACCURATELY REFLECT THE DIMENSIONS OF THE PALEO-RIVER CHANNEL OR MORE ACCURATELY REFLECT THE GEOMETRY OF AN EXHUMED RIVER-BELT DEPOSIT. THIS WILL ENABLE US TO DEVELOP A SET OF QUANTITATIVE SCALING RELATIONS BETWEEN OBSERVABLE MODERN RIDGE GEOMETRY AND RECONSTRUCTED PALEO-RIVER GEOMETRY. (3) MAP EXTENT OF INVERTED CHANNELS AND APPLY THE NEW SCALING RELATIONS FROM TASK 2 TO RECONSTRUCT PALEOHYDROLOGY FROM MEASUREMENTS OF INVERTED CHANNELS IN THE AEOLIS DORSA REGION OF MARS. THIS REGION IS OF PARTICULAR INTEREST BECAUSE IT HAS THE HIGHEST CONCENTRATION OF INVERTED CHANNELS ON THE PLANET SOME OF WHICH HAVE BEEN INTERPRETED AS EVIDENCE FOR CLIMATE CHANGE A GLOBAL OCEAN AND REGIONAL TECTONICS. EXPECTED RESULTS INCLUDE A QUANTITATIVE METHOD VALIDATED WITH EARTH ANALOGS FOR RECONSTRUCTING THE PALEO-HYDROLOGY OF ANCIENT RIVERS ACROSS MARS AND SPECIFIC INTERPRETATIONS FROM AEOLIS DORSA WITH IMPLICATIONS FOR THE GLOBAL HISTORY OF MARS. THE PROPOSED WORK SUPPORTS NASA S OBJECTIVES FOR IDENTIFICATION AND CHARACTERIZATION OF HABITABLE ENVIRONMENTS AND CLIMATE ON MARS THEIR CHANGES AND THEIR MODIFICATIONS TO THE SURFACE (PLANETARY SCIENCE DECADAL SURVEY PRIMARY QUESTION 5; MEPAG 2015 GOALS IA IIC IIIA) AND WILL ALSO SUPPORT INTERPRETATION OF CANDIDATE LANDING SITES FOR THE MARS 2020 ROVER.