EX1605L3 – Deepwater Exploration of the Marianas: The Northern Half

NOAA expedition EX1605L3 sampled hydrothermal vent sites, mud volcanoes, deep-sea coral and seamounts in and around the northern Marianas Trench Marine National Monument (MTMNM) and the Commonwealth of the Northern Mariana Islands (CNMI). Samples were obtained using the submersible Deep Discoverer. OSU marine repository archives the rock samples collected during the expedition. Archived samples include basalts, fossil corals, sulfides and more. Below are the samples recovered from each dive. 

For more information please visit the dedicated NOAA Page and Background Information

View and download data by expanding each of the dive sites below

Go back to the NOAA collections page

EX1605L3-D1 (FDM2)
 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D1-1 15.79°N, 146.01°E Siltstone A fine grained siltstone with slightly coarser grains within…
OSU-EX1605L3-D1-3 15.80°N, 146.01°E Basalt A highly altered basalt clast with zones of calcite and zeolites…

 

EX1605L3-D2 (Pagan)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D2-1 18.18°N, 145.82°E Andesite A andesite (or basalt) that contains plagioclase, othropyroxene and clinopyroxene phenocrysts…
OSU-EX1605L3-D2-3 18.18°N, 145.82°E Basalt A very fresh plagioclase basalt with abundant unfilled vesicles…
OSU-EX1605L3-D2-5 18.18°N, 145.82°E Basalt This basalt consists of olivine phenocrysts along with both olivine and plagioclase microcrysts within a glassy mesostasis…

 

EX1605L3-D3 (Maug)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D3-2 20.05°N, 145.23°E Fossil Coral A chunk of fossil coral with a few broken stems… No thin section No thin section
OSU-EX1605L3-D3-4 20.05°N, 145.23°E Basalt A plagioclase and olivine phyric basalt with a cryptocrystalline groundmass…

 

EX1605L3-D4 (Hadal Ridge)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D4-1 20.48°N, 146.98°E Siltstone A very fine carbonate rich siltstone…

 

EX1605L3-D5 (Ahyi)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D5-1 20.43°N, 145.03°E Basalt A highly phyric olivine and plagioclase phyric basalt with a glassy mesostasis…
OSU-EX1605L3-D5-3 20.43°N, 145.03°E Basalt A olivine and plagioclase phyric basalt with frequent disequilibrium textures…
OSU-EX1605L3-D5-4 20.43°N, 145.03°E Basalt A basalt with olivine-clinopyroxene-plagioclase phenocrysts…

 

EX1605L3-D6 (Supply Reef)
 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D6-1 20.15°N, 145.10°E Mn-crust A small and layered piece of seafloor debris… No thin section No thin section
OSU-EX1605L3-D6-2 20.15°N, 145.10°E Basalt A altered three-phase basalt with very coarse olivine and plagioclase phenocrysts as well some clinopyroxene grains…
OSU-EX1605L3-D6-4 20.15°N, 145.10°E Basalt A three phase basalt (olv, cpx and plagioclase) with a plagioclase rich groundmass….

 

EX1605L3-D7 (Chamorro)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D7-1 20.82°N, 144.71°E Pumice A glassy pumice with plagioclase and amphibole phenocrysts…
OSU-EX1605L3-D7-2 20.82°N, 144.71°E Hydrothermal Deposit It’s composed almost entirely of the same spherulitic mineral. I want to say it’s barite…
OSU-EX1605L3-D7-5 20.82°N, 144.71°E Pumice A amphibole and plagioclase phyric pumice with a glass dominate groundmass…

 

EX1605L3-D8 (Eifuku Seamount)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D8-1 21.41°N, 144.15°E Basalt A clinopyroxene, spinel and plagioclase phyric basalt with a fresh but fine grained groundmass….
OSU-EX1605L3-D8-3 21.41°N, 144.15°E Basalt A clinopyroxene, spinel and plagioclase phyric basalt with a fresh but fine grained groundmass….

 

EX1605L3-D9 (Daikoku Seamount)
 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D9-1 21.33°N, 144.19°E Hydrothermal Deposit A conglomerate consisting of rounded opaque Fe-sulfide grains, pyroxene, …
OSU-EX1605L3-D9-3 21.33°N, 144.19°E Hydrothermal Deposit Difficult to tell if this is a completely recrystallized basalt or a hydrothermal vent product…

 

EX1605L3-D10 (Stegosaurus Ridge)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D10-1 22.12°N, 145.14°E Volcaniclastic Appears to be a volcaniclastic deposit containing altered glass shards, opaque grains…
OSU-EX1605L3-D10-4 22.12°N, 145.14°E Siltstone A very fine grained siltstone with a few ~10-20 um grains of feldspars, pyroxene and opaques…
OSU-EX1605L3-D10-5 22.12°N, 145.14°E Pumice A few small pieces of pumice… No thin section No thin section

 

EX1605L3-D11 (North Forearc)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D11-1 22.40°N, 145.22°E Basalt A highly altered, coarse grained basalt/andesite consisting of primary plagioclase, clinopyroxene and spinel…
OSU-EX1605L3-D11-2 22.40°N, 145.22°E Serpentinite A serpentinzed gabbro or plagioclase-peridotite…

 

EX1605L3-D12 (Unnamed Forearc)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D12-1 21.57°N, 145.52°E Serpentinite A serpentinized mafic rock, likely a basalt but too pervasively recrystallized to tell…
OSU-EX1605L3-D12-3 21.57°N, 145.52°E Serpentinite A pervasively serpentinzed rock that appears to have contained either plagioclase and/or orthopyroxene grains…

 

EX1605L3-D13 (Twin Peaks)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D13-2 21.42°N, 145.89°E Sediment or Tephra Likely a siltstone but possibly a tephra deposit…
OSU-EX1605L3-D13-3 21.42°N, 145.89°E Sediment or Tephra Likely a siltstone but possibly a tephra deposit…

 

EX1605L3-D14 (Explorer Ridge)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D14-1 20.68°N, 145.09°E Tephra/Siltstone A multi-layered sedimentary rock with layers of tephra and fine silt…
OSU-EX1605L3-D14-3 20.68°N, 145.09°E Mud A plastic jar with fine grained mud…. No thin section No thin section

 

EX1605L3-D15 (Explorer Ridge)
 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D15-1 20.72°N, 145.06°E Breccia A sedimentary rock with a layer of fine and coarse volcaniclastic material…

 

EX1605L3-D18 (Unnamed Petit-Spot Volcano)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D18-1 20.62°N, 147.32°E Basalt A highly altered three phase basalt (olivine, clinopryoxene and plagioclase)…
OSU-EX1605L3-D18-2 20.62°N, 147.33°E Hyaloclastite A hyaloclastite with highly altered clasts…
OSU-EX1605L3-D18-4 20.62°N, 147.33°E Siltstone A very fine grained siltstone with a clay matrix…
OSU-EX1605L3-D18-5 20.62°N, 147.33°E Siltstone A brown-tan sedimentary rock… No thin section No thin section

 

EX1605L3-D19 (Vogt Guyot)
 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D19-1 19.80°N, 148.44°E Basalt A three phase basalt (plagioclase, cpx, olivine) with the olivine grains completely recrystallized to serpentine or iddingsite…

 

EX1605L3-D20 (Unnamed Subducting Guyot)
 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D20-1 18.45°N, 147.83°E Basalt A clinopyroxene and plagioclase phyric basalt with a somewhat coarse groundmass…

 

EX1605L3-D21 (Hadal wall)

 

Sample Location Rock Type Description Whole Rock Image TS Image TSX Image
OSU-EX1605L3-D21-1 16.56°N, 147.59°E Breccia A breccia or hyaloclastite with a few fresh plagioclase grains floating around and a lot of zeolites…
OSU-EX1605L3-D21-2 16.56°N, 147.59°E Basalt A sparsely phyric holocrystalline basalt…
OSU-EX1605L3-D21-4 16.56°N, 147.59°E Basalt A clinopyroxene and plagioclase phyric basalt with a cryptocrystalline groundmass…