DUSTY STAR-FORMING GALAXIES WITH INDIVIDUAL STAR FORMATION RATES ~>100MSUN/YR FORMED MOST OF THE STARS IN THE UNIVERSE AT EARLY EPOCHS (Z~1-2) YET THEIR PHYSICAL ORIGINS AND TRIGGERING WHETHER IT BE FROM MAJOR MERGERS OR SECULAR DISK-BOUND STAR-FORMATION IS STILL UNSOLVED. IN ASSESSING THE ROLE OF MAJOR GALAXY MERGERS (AMONGST DUSTY GALAXIES) TO COSMIC STAR FORMATION THE MEASUREMENT OF GALAXIES' STELLAR MASSES IS CRITICAL. STARBURSTS' STELLAR MASSES TELL US ABOUT THEIR PAST AVERAGE STAR FORMATION RATE AND WHETHER OR NOT THE CURRENT HIGH-SFR PHASE IS INDEED RARE (SHORT-LIVED) OR IN LINE WITH EXPECTATION. CAN WE DEFINITIVELY MEASURE WHETHER THE OCCURRENCE OF MAJOR MERGERS AT A GIVEN STAR-FORMATION RATE VARIES WITH STELLAR MASS AS PREDICTED? OR ARE HIGH STAR FORMATION RATES SIMPLY ALWAYS INDICATIVE OF SHORT-LIVED BURSTS? HERE WE PROPOSE FUNDING TO ANALYZE AND INCORPORATE OUR PRIORITY 1 CYCLE 12 SPITZER DATA WITH A UNIQUE DATASET TO ANSWER THESE QUESTIONS. OUR SURVEY CONSISTS OF A NEW 1.77DEG^2 EXTRAGALACTIC LEGACY FIELD WHICH HAS VERY UNIQUE DEEP HIGH-RESOLUTION RADIO INTERFEROMETRIC COVERAGE FROM THE E-MERLIN SUPERCLASS SURVEY; THE DATASET'S RADIO CONTINUUM MAPPING WILL ALLOW A UNIQUE MORPHOLOGICAL MEASUREMENT OF OBSCURED STAR FORMATION IN ~5000 STARBURSTS PROBING THE MERGER FRACTION OF DUSTY GALAXIES (WHICH ARE TOO DUSTY FOR HST MORPHOLOGY). CRITICALLY SPITZER IRAC 3.6UM AND 4.5UM ALLOW CALCULATION OF GALAXIES' STELLAR MASSES AND ALLOW US TO DIRECTLY TEST IF HIGHER MASS STARBURSTS ARE LESS LIKELY TO EXHIBIT CLUMPY MERGING MORPHOLOGIES THAN THEIR LOWER MASS COUNTERPARTS (A KEY COROLLARY TO THE GALAXIES `MAIN SEQUENCE' FRAMEWORK OR THE TIGHT RELATIONSHIP BETWEEN GALAXIES STELLAR MASSES AND STAR-FORMATION RATES). IN ADDITION IRAC COVERAGE PROVIDES AN INDEPENDENT AGN INDICATOR (STEEP MID-IR POWERLAW) WHICH WILL IMPROVE THE QUALITY OF PHOTOMETRIC REDSHIFTS IN THE FIELD AND WILL PROVIDE CRUCIAL NEAR-IR POSITIONAL COUNTERPARTS FOR FUTURE SUBMILLIMETER COVERAGE. THIS PROPOSAL WILL FUND THE INCORPORATION OF THE SPITZER DATASET INTO THE SUPERCLASS SURVEY DATA PRODUCTS: PHOTOMETRIC REDSHIFTS THE COMPUTATION OF GALAXIES STELLAR MASSES DIAGNOSTIC OF AGN AND SUBMILLIMETER COUNTERPART IDENTIFICATION.