Decadal to Orbital Links Between Climate, Productivity, and Denitrification on the Peru Margin; Do Models of Persistent EL Ni±o or La Ni±a Conditions Apply?

这是一项初步研究，旨在确定能否通过对秘鲁边缘沉积岩心的烯酮测年和磁性古强度来确定可靠的年代学。如果是这样的话，接下来的研究将调查秘鲁边缘的反硝化带，它与生产力和厄尔尼诺/拉尼娜循环的可能联系，以及导致反硝化的水柱中的亚氧条件与过去60k年十年至轨道时间尺度上的快速气候变化事件的关联程度。这项研究将利用在ODP112航段钻探的数据，最终将是对不同水深的几个岩心进行的多代理研究。大多数岩心只含有一小部分碳酸盐，一些岩心是层状的。对于有形式的岩心，将使用14C孔和S 18O孔建立高分辨率年代学，而对于没有孔的岩心，将结合地磁古地磁强度、烷酮14C和光学方法建立高分辨率年代学。在这项初步研究中，将对两个岩心进行研究，以建立年表，其中一个岩心的孔洞丰度有限，另一个岩心没有孔洞。

This is a pilot study to determine whether a reliable chronology can be developed via alkenone dating and magnetic paleointensity for sediment cores from the Peru margin. If so, then follow on studies will investigate the denitrification zone of the Peru margin, its possible links with productivity and El Nino/ La Nina cycles, and the extent to which suboxic conditions in the water column, leadng to denitification, are correlated with rapid climate change events on decadal to orbital time scales for the last 60 k years. The study will utilize scores drilled on ODP Leg 112, and eventually will be a multiproxy study of several cores in a variety of water depths. Most of the cores contain only a small carbonate fraction and some of the cores are laminated. For cores containing forms, high resolution chronologies will be established with foram 14 C and S 18 O and for those without forams a combination of geomagnetic paleointensity, alkenone 14C, and optical methods will be used. In this pilot study, two cores, one with limited foram abundances and one with no forams, will be studied to establish chronologies.