Publication Date:
2024-07-01
Description:
Miocene paleoceanographic evolution exhibits major changes resulting from the opening and closing of passages, the subsequent changes in oceanic circulation, and development of major Antarctic glaciation. The consequences and timing of these events can be observed in variations in the distribution of deep-sea hiatuses, sedimentation patterns, and biogeographic distribution of planktic organisms.
The opening of the Drake Passage in the latest Oligocene to early Miocene (25-20 Ma) resulted in the establishment of the deep circumpolar current, which led to thermal isolation of Antarctica and increased global cooling. This development was associated with a major turnover in planktic organisms, resulting in the evolution of Neogene assemblages and the eventual extinction of Paleogene assemblages. The erosive patterns of two widespread hiatuses (PH, 23.0-22.5 Ma; and NH 1, 20-18 Ma) indicate that a deep circumequatorial circulation existed at this time, characterized by a broad band of carbonate-ooze deposition. Siliceous sedimentation was restricted to the North Atlantic and a narrow band around Antarctica.
A major reorganization in deep-sea sedimentation and hiatus distribution patterns occurred near the early/middle Miocene boundary, apparently resulting from changes in oceanic circulation. Beginning at this time, deep-sea erosion occurred throughout the Caribbean (hiatus NH 2, 16-15 Ma), suggesting disruption of the deep circumequatorial circulation and northward deflection of deep currents, and/or intensification of the Gulf Stream. Sediment distribution patterns changed dramatically with the sudden appearance of siliceous-ooze deposition in the marginal and east equatorial North Pacific by 16.0 to 15.5 Ma, coincident with the decline of siliceous sedimentation in the North Atlantic. This silica switch may have been caused by the introduction of Norwegian Overflow Water into the North Atlantic acting as a barrier to outcropping of silica-rich Antarctic Bottom Water.
The main aspects of the present oceanic circulation system and sediment distribution pattern were established by 13.5 to 12.5 Ma (hiatus NH 3), coincident with the establishment of a major East Antarctic ice cap. Antarctic glaciation resulted in a broadening belt of siliceous-ooze deposition around Antarctica, increased siliceous sedimentation in the marginal and east equatorial North Pacific and Indian Oceans, and further northward restriction of siliceous sediments in the North Atlantic. Periodic cool climatic events were accompanied by lower eustatic sea levels and widespread deep-sea erosion at 12 to 11 Ma (NH 4), 10 to 9 Ma (NH 5), 7.5 to 6.2 Ma (NH 6), and 5.2 to 4.7 Ma (NH 7).
Keywords:
10-90; 10-97; 11-101; 11-102; 11-103; 11-104; 12-111; 12-116; 12-119; 14-141; 14-142; 15-149; 15-150; 15-151; 15-153; 15-154; 16-155; 16-157; 16-158; 16-159; 16-160; 16-161; 16-162; 16-163; 17-164; 17-165; 17-166; 17-168; 17-170; 17-171; 18-172; 18-173; 19-183; 19-192; 20-199; 20-200; 20-202; 21-205; 21-206; 21-207; 21-208; 21-209; 21-210; 22-212; 22-213; 22-214; 22-215; 22-216; 22-218; 23-220; 23-221; 23-223; 23-224; 24-231; 24-234; 24-236; 24-237; 24-238; 26-251; 26-253; 26-254; 26-255; 26-256; 26-257; 26-258; 27-259; 28-264; 28-265; 28-266; 28-273; 28-274; 29-275; 29-276; 29-277; 29-278; 29-279; 29-280; 29-281; 29-282; 29-283; 29-284; 30-285; 30-286; 30-287; 30-288; 30-289; 31-290; 31-292; 31-296; 3-14; 3-15; 3-17; 3-20; 32-304; 32-305; 32-306; 32-307; 32-308; 32-310; 32-311; 32-313; 33-315; 33-316; 33-317; 33-318; 34-319; 36-327; 36-328; 36-329; 37-334; 38-336; 38-338; 38-339; 38-352; 39-354; 39-355; 39-356; 39-357; 39-359; 40-360; 40-362; 40-363; 40-364; 41-366; 41-368; 41-369; 42-372; 4-25; 4-29; 4-30; 43-386; 44-391; 45-396; 47-397; 47-398; 48-400; 48-404; 48-405; 48-406; 49-407; 49-408; 49-410; 5-34; 5-36; 5-38; 5-39; 5-40; 5-41; 5-42; 55-430; 55-431; 55-432; 55-433; 56-436; 57-438; 57-439; 57-440; 58-443; 58-444; 58-445; 59-447; 59-448; 59-449; 59-450; 59-451; 61-462; 62-463; 62-464; 62-465; 62-466; 63-467; 63-468; 63-469; 63-470; 63-471; 63-472; 6-45; 6-46; 6-47; 6-48; 6-49; 6-50; 6-51; 6-52; 6-53; 6-55; 6-56; 67-495; 68-503; 7-61; 7-62; 7-63; 7-64; 7-65; 7-66; 7-67; 8-68; 8-69; 8-70; 8-71; 8-72; 8-73; 8-74; 8-75; 9-77; 9-78; 9-79; 9-83; 9-84; Antarctic Ocean; Antarctic Ocean/BASIN; Antarctic Ocean/CONT RISE; Antarctic Ocean/PLATEAU; Antarctic Ocean/RIDGE; Antarctic Ocean/Tasman Sea; Antarctic Ocean/Tasman Sea/CONT RISE; Antarctic Ocean/Tasman Sea/PLATEAU; Antarctic Ocean/Tasman Sea/RIDGE; Caribbean Sea/BASIN; Caribbean Sea/GAP; Caribbean Sea/RIDGE; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Gulf of Mexico/BANK; Gulf of Mexico/PLAIN; Indian Ocean//BASIN; Indian Ocean//FAN; Indian Ocean//FRACTURE ZONE; Indian Ocean//PLATEAU; Indian Ocean//RIDGE; Indian Ocean/Arabian Sea/HILL; Indian Ocean/Arabian Sea/PLAIN; Indian Ocean/Arabian Sea/RIDGE; Indian Ocean/Gulf of Aden/BASIN; Leg10; Leg11; Leg12; Leg14; Leg15; Leg16; Leg17; Leg18; Leg19; Leg20; Leg21; Leg22; Leg23; Leg24; Leg26; Leg27; Leg28; Leg29; Leg3; Leg30; Leg31; Leg32; Leg33; Leg34; Leg36; Leg37; Leg38; Leg39; Leg4; Leg40; Leg41; Leg42; Leg43; Leg44; Leg45; Leg47; Leg48; Leg49; Leg5; Leg55; Leg56; Leg57; Leg58; Leg59; Leg6; Leg61; Leg62; Leg63; Leg67; Leg68; Leg7; Leg8; Leg9; Mediterranean Sea/BASIN; North Atlantic/BASIN; North Atlantic/CONT RISE; North Atlantic/CONT SLOPE; North Atlantic/DIAPIR; North Atlantic/KNOLL; North Atlantic/Norwegian Sea; North Atlantic/Norwegian Sea/DIAPIR; North Atlantic/Norwegian Sea/PLATEAU; North Atlantic/PLAIN; North Atlantic/PLATEAU; North Atlantic/RIDGE; North Atlantic/SEAMOUNT; North Atlantic/SEDIMENT POND; North Pacific; North Pacific/ABYSSAL FLOOR; North Pacific/BASIN; North Pacific/CONT RISE; North Pacific/ESCARPMENT; North Pacific/FAN; North Pacific/FLANK; North Pacific/GAP; North Pacific/GUYOT; North Pacific/HILL; North Pacific/Philippine Sea/BASIN; North Pacific/Philippine Sea/CONT RISE; North Pacific/Philippine Sea/RIDGE; North Pacific/PLAIN; North Pacific/PLATEAU; North Pacific/RIDGE; North Pacific/SEAMOUNT; North Pacific/SEDIMENT POND; North Pacific/SLOPE; North Pacific/TERRACE; North Pacific/TRENCH; North Pacific/VALLEY; South Atlantic; South Atlantic/BANK; South Atlantic/BASIN; South Atlantic/CONT RISE; South Atlantic/HILL; South Atlantic/PLATEAU; South Atlantic/RIDGE; South Atlantic/SEAMOUNT; South Atlantic/SYNCLINE; South Atlantic/VALLEY; South Pacific; South Pacific/BASIN; South Pacific/CONT RISE; South Pacific/Coral Sea; South Pacific/Coral Sea/BASIN; South Pacific/Coral Sea/PLATEAU; South Pacific/PLATEAU; South Pacific/RIDGE; South Pacific/Tasman Sea/BASIN; South Pacific/Tasman Sea/CONT RISE
Type:
Dataset
Format:
application/zip, 3 datasets
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