Paul Bown - IODP Expedition 320 participation

1.古近纪泥炭拼接地层基准的相互标定对始新世-中新世进行了船上和巡航后钙质超微化石生物地层学研究，并将这些数据与其他泥炭地层学家的数据进行了整合。完成天文标定的古近纪地层“巨型拼接”是320/321远征的主要目标。2.始新世高温作用下的钙质超微化石演化与始新世气候优化早、中期始新世早期至中期，超微化石多样性增加，达到新生代最大值。我将调查这种增加的时间和结构，并检查气候变化是否在这个时候海洋浮游生物的进化中发挥了重要作用。如果恢复早期始新世过热间隔，我将以高分辨率研究超微化石的响应，以测试温度和/或海洋化学变化(如酸化)对超微化石丰度、多样性和演化速度的强迫效应。3.在赤道太平洋以前的记录中，发现了始新世中晚期碳酸盐和二氧化硅堆积事件的气候、碳酸盐堆积和超微化石演化，并与浮游生产力的变化和全球气候变化有关。在这段时间间隔内，超微化石的多样性也急剧下降，可以说，该小组从未完全恢复过来。我将在短时间尺度和长时间尺度上生成定量的超微化石丰度和多样性记录，以研究超微化石生产力与进化、碳酸盐堆积与古气候/古海洋学之间的关系。具体地说，我感兴趣的是始新世中期(MECO；42 Ma)的超微化石记录，以及在始新世/渐新世过渡之前(48-34 Ma)的生物堆积和碳酸盐补偿深度(CCD)事件。我还将调查遗址接近CCD时纳米化石保存的性质，特别是它对保存下来的多样性和替代记录的影响。4.始新世-渐新世过渡(EOT)--调查海洋化学与浮游生物演化之间的联系跨越EOT的浮游生物生态系统的重大重组表明，南极冰盖的扩张与低纬表层海洋环境的显著扰动是一致的。来自钙质超微化石组合的证据表明，这可能是由于养分可获得性的普遍增加。在EOT之前，CCD明显变浅，阻碍了从深海沉积物中产生可比记录。我们建议测量超微化石物种的绝对丰度，并结合旋回地层学年龄模型，量化跨EOT的超微化石累积速率。我们还将积极与泥炭科学家合作，生产各种碳酸盐、二氧化硅、纳米化石和有孔虫的堆积率。5.早中新世冰期(Mi-1)与浮游生物生态系统相对较短但意义重大的早中新世冰期Mi-1在某些方面与EOT气候事件相似。然而，在浮游生态系统中几乎没有观察到对Mi-1的反应。我们将把目标4中使用的方法应用于米-1(PEAT-6C)。这是目标4的延伸，我们将与泥炭纳米化石生物地层学家合作，他们将这一间隔作为主要目标。

1. Intercalibration of stratigraphic datums from the Paleogene PEAT splice Undertake shipboard and post-cruise calcareous nannofossil biostratigraphy for the Eocene-Miocene interval and integrate these data with those from other PEAT stratigraphers. The completion of a astronomically calibrated Paleogene stratigraphic 'mega-splice' is an Expeditions 320/321 primary objective. 2. Calcareous nannofossil evolution through Eocene hyperthermals and the Eocene climatic optimum The early to middle Eocene saw a rise in nannofossil diversity to a Cenozoic maximum. I will investigate the timing and structure of this increase and examine whether climatic shifts played a significant role in the evolution of the oceanic plankton at this time. If early Eocene hyperthermal intervals are recovered I will investigate the nannofossil response at high resolution to test for the forcing effects of temperature and/or ocean chemistry changes (e.g. acidification) on nannofossil abundance, diversity and evolutionary rates. 3. Climate, carbonate accumulation and nannofossil evolution through the middle to late Eocene Carbonate and silica accumulation events have been identified in previous records from the equatorial Pacific and linked to changes in planktonic productivity and global climate shifts. This time interval also saw a precipitous decline in the diversity of nannofossils from which the group has arguably never completely recovered. I will generate quantitative nannofossil abundance and diversity records on short and long timescales in order to examine the relationships between nannofossil productivity and evolution, carbonate accumulation and paleoclimate/paleoceanography. In detail, I am interested in the nannofossil record across the Middle Eocene climatic optimum (MECO; 42Ma) and the biogenic accumulation and carbonate compensation depth (CCD) events that follow, and precede the Eocene/Oligocene transition (48-34Ma). I will also investigate the nature of nannofossil preservation as sites approach the CCD, in particular its influence on preserved diversity and proxy records. 4. Eocene-Oligocene transition (EOT) - investigating links between ocean chemistry and plankton evolution A major restructuring in plankton ecosystems across the EOT suggests that the expansion of Antarctic ice sheets is coincident with a significant perturbation in low-latitude surface ocean environments. Evidence from calcareous nannofossil assemblages indicates that this may be due to a widespread increase in nutrient availability. A marked shoaling of the CCD immediately prior to the EOT has hampered the production of a comparable record from deep-sea sediments. We propose to measure absolute nannofossil species abundances and, combined with the cyclostratigraphic age model, quantify nannofossil accumulation rates across the EOT. We would also actively collaborate with PEAT scientists in the production of the full range of carbonate, silica, nannofossil and foraminiferal accumulation rates. 5. Early Miocene glaciation (Mi-1) and the plankton ecosystem The relatively short but significant early Miocene glacial episode, Mi-1, is in some ways similar to the EOT climate event. There has, however, been little observed response within planktonic ecosystems to Mi-1. We would apply the methodology used in objective 4 to Mi-1 (PEAT-6C). This is an extension of objective 4 and we will collaborate with PEAT nannofossil biostratigraphers who have this interval as a primary objective.